Differing Site Condition Claims: Technical Analysis ... · Risk ... evaluation of entitlement in...

Differing Site Condition Claims:

Technical Analysis, Presentation, and

Adjudication of Entitlement

by

PETER J. TARKOY, PH.D. GEOTECHNICAL AND UNDERGROUND CONSTRUCTION CONSULTANT

Dr. Peter J. Tarkoy 176 Western Avenue, MA 01770 e-Fax: (509) 479-5400 Office: (508) 650-3600 E-mail: [email protected]

PRIVATE COMMUNICATION -- BUSINESS CONFIDENTIAL This is an unpublished work of authorship protected by the copyright laws of the USA.

It may not be reproduced, copied, published, or loaned to other parties without the express written consent of the author.

Copyright 1991-2013 by Peter J. Tarkoy

26-Dec-12

TABLE OF CONTENTS 1. Introduction ................................................................................................................1

Concept of Differing Site Conditions...................................................................................... 1 Historical Development and Role of the Differing Site Condition Clause .......................... 1 Rationale of this Book.............................................................................................................. 2 Intent and Content .................................................................................................................... 4

Outline ................................................................................................................................... 4 Case Histories ....................................................................................................................... 4 Exercises ............................................................................................................................... 5

2. Fundamental Perspectives, Concerns, Privileges, and Responsibilities .............6 Owner......................................................................................................................................... 6

Desire for a Working Facility ................................................................................................. 6 Cost Considerations .............................................................................................................. 6 Schedule Considerations ...................................................................................................... 7 Risk........................................................................................................................................ 8

Engineer .................................................................................................................................... 9 Project Feasibility Stage........................................................................................................ 9 Design Stage ....................................................................................................................... 10

Site Investigation.......................................................................................................................... 11 Geotechnical Data Reports .......................................................................................................... 12 Geotechnical Interpretive Reports ................................................................................................ 12 Presentation of Exploration Data.................................................................................................. 12 Geotechnical Baseline Reports .................................................................................................... 15

Construction Stage.............................................................................................................. 16 Contractor ............................................................................................................................... 16

Contract Provisions ............................................................................................................. 16 Site Investigations ............................................................................................................... 17 Reliance............................................................................................................................... 19 Notice................................................................................................................................... 19 Mitigating Impact ................................................................................................................. 20

Record Keeping ...................................................................................................................... 20 Dimensions of Time and Space .......................................................................................... 20 Responsibilities of the Owner, Engineer, and Contractor ................................................... 21 Records ............................................................................................................................... 21

Pre-bid.......................................................................................................................................... 22 Bid ................................................................................................................................................ 22 Pre-Notice to Proceed.................................................................................................................. 22 Contract........................................................................................................................................ 23 Construction ................................................................................................................................. 23

3. Elements of a Differing Site Condition...................................................................25 The Differing Site Condition Clause ..................................................................................... 25 List of Technical Elements .................................................................................................... 27 Site Conditions ....................................................................................................................... 29

Reasonable Anticipated Conditions .................................................................................... 29 Credible Encountered Conditions........................................................................................ 31 Differences between Anticipated & Encountered Conditions.............................................. 32

Construction Performance .................................................................................................... 33 Reasonable Anticipated Construction Performance ........................................................... 34 Verifiable Encountered Construction Performance ............................................................. 35 Differences between Anticipated and Encountered Performance ...................................... 36

Stable Geology, Construction Disturbance, & "Ground Response"................................. 37 Cause and Effect Relationships............................................................................................ 38 Impact ...................................................................................................................................... 39 Fulfilling Contract Requirements.......................................................................................... 41 Other Considerations / Other Causes .................................................................................. 42

4. The Process of Resolution......................................................................................44 Analysis ................................................................................................................................... 44 Presentation ............................................................................................................................ 44 Dealing with Parties................................................................................................................ 44

Contractor............................................................................................................................ 44 Attorneys ............................................................................................................................. 45 Experts ................................................................................................................................ 45 Judges ................................................................................................................................. 46 Arbitrators / Arbitration......................................................................................................... 46 Disputes Review Boards ..................................................................................................... 47 Juries ................................................................................................................................... 48

5. Recognizing Differing Site Conditions...................................................................49 Difference in Performance..................................................................................................... 49 Difference in Conditions ........................................................................................................ 50

6. Exercises ..................................................................................................................53 Introduction............................................................................................................................. 53 Exercise 1 - Development of Anticipated Conditions and Performance .......................... 53

Description of Project “A-1” ................................................................................................. 53 Assignment for Project “A-1” ............................................................................................... 53 Data for Project “A-1”........................................................................................................... 55 Solutions for Project A-1:..................................................................................................... 59

Exercise 2 - Presentation, Analysis, and Approval of a DSC Claim.................................. 60 Description of Project A-2:................................................................................................... 60 Assignment for Project “A-2” ............................................................................................... 60 Data for Project “A-2”........................................................................................................... 61 Solutions for Project “A-2” ................................................................................................... 64 Outcome of Project “A-2”..................................................................................................... 65

Exercise 3 – Presentation, Analysis, and Adjudication of a DSC Claim........................... 67 Description of Project “B-1” ................................................................................................. 67 Assignment for Project “B-1” ............................................................................................... 67 Data for Project “B-1”........................................................................................................... 68 Solutions for Project “B-1” ................................................................................................... 73

Exercise 4 – Presentation, Analysis, and Adjudication of a DSC Claim........................... 74 Description of Project “B-2” ................................................................................................. 74 Assignment for Project “B-2” ............................................................................................... 74 Evaluation of Project “B-2” .................................................................................................. 74 Data for Project “B-2”........................................................................................................... 75

Solutions for Project “B-2” ................................................................................................... 77 Outcome of Project “B-2”..................................................................................................... 80

7. References.................................................................................................................81

8. Tables........................................................................................................................83

9. Figures ......................................................................................................................95

10. Appendices...........................................................................................................106 Appendix A: Forms for Effective Documentation of Encountered Conditions and Construction Performance.......................................................................................................................... 107 Appendix B: The Stuff That Claims Are Made Of ............................................................. 117

LIST OF TABLES Table 1: Recommendations for the Presentation of Reasonable Anticipated Conditions............. 84 Table 2: Recommendations for the Review of Reasonable Anticipated Conditions ..................... 85 Table 3: Recommendations for the Presentation of Verifiable Encountered Conditions .............. 85 Table 4: Recommendations for the Review of Verifiable Encountered Conditions....................... 85 Table 5: Recommendations for the Presentation of Differences in Conditions ............................. 86 Table 6: Recommendations for the Review of Differences in Conditions ..................................... 86 Table 7: Recommendations for the Presentation of Reasonable Anticipated Performance ......... 88 Table 8: Recommendations for the Review of Reasonable Anticipated Performance.................. 89 Table 9: Recommendations for the Presentation of Verifiable Encountered Performance........... 89 Table 10: Recommendations for the Review of Verifiable Encountered Performance ................. 90 Table 11: Recommendations for the Presentation of Differences in Performance ....................... 90 Table 12: Recommendations for the Review of Differences in Performance................................ 91 Table 13: Recommendations for the Presentation of Cause and Effect Relationships................. 91 Table 14: Recommendations for the Review of Cause and Effect Relationships ......................... 92 Table 15: Recommendations for the Presentation of IMPACT...................................................... 92 Table 16: Recommendations for the Review of Impact................................................................. 93 Table 17: Recommendations for the Presentation of Fulfilling Contract Requirements................ 93 Table 18: Recommendations for the Review of Fulfilling Contract Requirements ........................ 94 Table 19: Recommendations for the Presentation That No Other Conditions Were Responsible 94 Table 20: Recommendations for the Review to Determine That No Other Conditions Were Responsible

.......................................................................................................................................... 94

LIST OF FIGURES Figure 1: REASONABLE ANTICIPATED CONDITIONS (UCS Hi-Lo)......................................... 96 Figure 2: UNREASONABLE ANTICIPATED CONDITIONS (Bar) ............................................... 96 Figure 3: CREDIBLE ENCOUNTERED DATA (Hi-Lo) .................................................................. 96 Figure 4: NON-CREDIBLE ENCOUNTERED DATA (Frozen Weir).............................................. 97 Figure 5: DIFFERENCE IN CONDITIONS (by Tunnel Zone)....................................................... 97 Figure 6: DIFFERENCE IN CONDITIONS (UCS / Hi-Lo)............................................................. 97 Figure 7: NO DIFFERENCE IN CONDITIONS (Water Inflow) ..................................................... 98 Figure 8: BASIS OF REASONABLE PERFORMANCE ............................................................... 98 Figure 9: BASIS OF UNREASONABLE PERFORMANCE .......................................................... 98 Figure 10: CATERPILLAR RIPPABILITY CHART........................................................................ 99 Figure 11: UNREASONABLE ANTICIPATED PERFORMANCE................................................ 100 Figure 12: VERIFIABLE PERFORMANCE (Dredge Rate).......................................................... 100 Figure 13: UNVERIFIABLE PERFORMANCE (Downtime) ......................................................... 100 Figure 14: DIFFERENCE IN PERFORMANCE (Rate/3-D Surface)............................................ 100 Figure 15: NO DIFFERENCE IN PERFORMANCE (Dredge Capacity) ...................................... 101 Figure 16: STABILITY, CONSTRUCTION DISTURBANCE, AND CONSEQUENCES .............. 102 Figure 17: CAUSE AND EFFECT RELATIONSHIP (Quartz Content-Penetration Rate)............ 103 Figure 18: CAUSE AND EFFECT RELATIONSHIP (UCS-Drill Rate) ......................................... 103 Figure 19: NO CAUSE AND EFFECT RELATIONSHIP (Weekly Inflow).................................... 103 Figure 20: NO CAUSE AND EFFECT RELATIONSHIP (Daily Inflow)........................................ 104 Figure 21: IMPACT OF OVERBREAK (Time-Progress) ............................................................. 104 Figure 22: IMPACT OF OVERBREAK (MMSD - Labor Efficiency) ............................................. 104 Figure 23: NO ADVERSE IMPACT (Dredging Gravel)................................................................ 105 Figure 24: EQUIPMENT CONDITION (Pump Efficiency)............................................................ 105

LIST OF EXHIBITS Exhibit A-1: Profile of Courthouse Drain ....................................................................................... 55 Exhibit A-2: Boring Logs B-1 & 2 for Courthouse Drain................................................................ 56 Exhibit A-3: Tabulation of Anticipated Site Conditions (Courthouse Drain).................................. 58 Exhibit A-4: Applicable Empirical Pipe-Jacking Experience ......................................................... 58 Exhibit A-5: Construction Record Tabulation/Calculations for Courthouse Drain ........................ 61 Exhibit A-6: Exercise in the Difference in Conditions (Courthouse Drain).................................... 62 Exhibit A-7: Exercise in the Difference in Performance (Courthouse Drain) ................................ 62 Exhibit A-8: Exercise in the Cause and Effect Relationship (Courthouse Drain) ......................... 63 Exhibit A-9: Exercise in Impact (Courthouse Drain) ..................................................................... 63 Exhibit B- 1: Bid Schedule ............................................................................................................ 68 Exhibit B- 2: Rock Removal Bid Item............................................................................................ 68 Exhibit B- 3: Specified Method of Rock Excavation Measurement .............................................. 68 Exhibit B- 4: Classifications & Definitions (a) for Rock Excavation .............................................. 68 Exhibit B- 5: Classifications & Definitions (b) for Rock Excavation .............................................. 69 Exhibit B- 6: Encountered Rock Quantities To Date..................................................................... 69 Exhibit B- 7: Exercise in the Difference in Rock Quantities .......................................................... 69 Exhibit B- 8: Exercise in Entitlement............................................................................................. 70 Exhibit B- 9: Exercise in the Effect of Unanticipated Rock ........................................................... 71 Exhibit B- 10: Exercise in the Impact of Unanticipated Rock......................................................... 72

LIST OF FORMS FORM 1: ROCK TUNNEL GEOLOGICAL LOG .......................................................................... 108 FORM 2: TBM PERFORMANCE SHIFT REPORT ..................................................................... 109 FORM 3: PILE SOCKET DRILLING REPORT............................................................................ 111 FORM 4: PIPE JACKING REPORT ............................................................................................ 113 FORM 5: SOFT GROUND EXCAVATION REPORT .................................................................. 115

Dedication

To Peter Paul, the magnificent and grand inspiration of my life.

Preface

• Essential to get into the frame of reference • Need to do the exercises • Need to take the claimant’s position, • Need to take the respondent’s position, and • Need to learn to be an independent observer and adjudicator.

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Prepared by Peter J. Tarkoy, GeoConSol, Inc ………………………………………………………………………………….. 26-Dec-12 / Page 1

This is an unpublished work of authorship protected by the copyright laws of the USA. It may not be reproduced, copied, published, or loaned to other parties without the express written consent of the author. Copyright 1991-2006 by Peter J. Tarkoy

1. INTRODUCTION Concept of Differing Site Conditions The Differing Site Condition Clause has created some problems it was meant to solve. For one, claims for extras have become routine, and often a contractor will choose this clause as the most convenient tool to recover for cost overruns, recover from misinterpretation of anticipated conditions, operational inefficiencies, poor project coordination, and over-optimism. On the other hand, owners and engineers have been known to take the hard line when asked to compensate contractors for legitimate claims for unforeseen conditions and associated costs. It has not been uncommon for engineers to evaluate a Differing Site Condition (DSC) claim by the amount of money claimed rather than the technical merits of the claim. The Clause was introduced by the federal government in to lower the price of construction by eliminating the contractor's inclusion of money for contingencies. In turn, contractors were promised to be compensated for unanticipated site conditions. What can a contractor provide the owner or engineer to illustrate that a legitimate differing site condition was encountered? What should the owner or engineer look for in evaluating a differing site condition claim for entitlement? It would be desirable for all parties to adhere to common elements that must be satisfied in the presentation and evaluation of entitlement in differing site condition claims, such as:

1. A technical punch list, 2. Quantitative and graphic representations, 3. Consistent with the intent of DSC clause, 4. Based on the underlying philosophy, law, and precedents, and 5. Elements that are bilaterally agreeable.

The fundamental basis of a claim that reaches the courts must be the legal framework populated by the facts of the case. However, until this work, there has been no framework provided for the facts of the case. Historical Development and Role of the Differing Site Condition Clause The first "changed conditions" clause was used in November 22, 1921. This clause was included as a standard form of general conditions for construction contracts that was completed on August 20, 1926, and subsequently approved by the President of the United States for use by the federal government (Mathews, 1985) in their contracts. To this day, Federal Regulations mandate its use in U.S. Government contracts and in contracts with Federal funding, even if the funding is only partial.




Provisions similar to the “changed conditions” clause, which was later renamed as “differing site conditions” have been incorporated into the standard contract documents by The American Institute of Architects (AIA), The Engineers Joint Contract Documents Committee (American Engineers Council, American Society of Civil Engineers, National Professional Engineers), The American Society of Civil Engineers, in collaboration with the Associated General Contractors of America, The American Association of State Highway and Transportation Officials, and numerous state and municipal governments Over an 85-year history, the wording has had minor refinement, however, principle remains. In effect, without the DSC clause:

1. The owner would convey all risk to the contractor, 2. The contractor would always include an amount for contingencies, and 3. The owner would always pay a premium for the contractor's contingency costs

for adverse conditions (encountered or not). It was the intention that the DSC clause avoid paying for contingencies and pay only for unanticipated conditions, if encountered. Rationale of this Book The basis of this undertaking was the re-occurrence of similar issues, problems, and arguments in the consulting practice of the author. These re-occurrences catalogued a series, many similar, of consistent elements and issues facing professionals charged with analyzing, presenting, and evaluating differing site condition claims. Most of these principles were never before defined in the geological, engineering, and the construction domains, the forum and setting for DSC claims. Our role has been on behalf of the contractor, the engineer, and the owner, always as impartial and independent evaluators. Since the material in this book is based on:

1. practical experience, 2. various forums, and 3. various jurisdictions,

it may not be precisely and consistently consistent with experience in various jurisdictions, with all case law, or individual experience. Furthermore, the interpretation and sometimes even the intent of common law has changed and/or evolved throughout time.




The technical materials and bases for entitlement for differing site conditions presented in this book are independent of the vagaries of jurisdictions, forums, contract specifics, and their application. Consequently, project references in most cases are confidential. The reader is asked to put aside their experiences and rebuild the principles without bias toward their own past experiences. It is possible and recommended that the reader put themselves in a position that they are not familiar with, to experience the perspectives of an owner, engineer, or contractor. This can enrich the opportunity to move forward when your own position may not. Principles presented herein, are consistent with thinking in various precepts of the differing site condition principles, schemes of risk sharing, disputes resolution, and equitable adjustment concepts. It is certain that readers will have their own "story" of an unreasonable owner, engineer, lawyer, or contractor. However, it is suggested to put such experience aside when attempting to learn about the important technical issues from the position of a "universal observer". The reader's purchase and reading of these guidelines indicates willingness to learn and improve on some unsatisfactory situation. The basis of the case history material in the examples presented has come from the following jurisdictions:

1. Mediation,

2. Arbitration (single and multiple member panels),

3. Disputes Review Boards (single and multiple member panels),

4. Courts (judges and juries),

a. Municipal, State, Federal, b. Engineering Board of Contract Appeals, and c. Armed Services Board of Contract Appeals.

5. Negotiation.

Although this text does not offer legal advice or claim to adhere to any specific letters of the law, the experience and concepts presented in this guide are consistent with the intent (underlying philosophy) of the law and the various manifestations of applicable law. It has been our fortunate experience to work for reasonable owners, honest engineers and contractors, and competent attorneys who have been willing to look at the facts and listen to our findings and recommendations. One would be hard pressed to duplicate that experience in a classroom.




Intent and Content The intent in the preparation of this book is to provide simple, technical, universal elements, according to which differing site conditions can be analyzed and presented by the contractor, analyzed by the engineer, legitimately approved or rejected by the owner, and resolved for the benefit of all within the intent of the law and the differing site condition clause. Perspectives of various parties will be examined to provide an understanding of rationale, conduct, and outlook. The presentation utilizes case history examples that illustrate situations commonly encountered and which may reflect a wide range of experiences with various and common issues.

Outline The book will cover the technical elements of a differing site condition necessary for the establishment of entitlement and the following associated topics:

1. Definition of differing site condition clauses, 2. Geotechnical elements of a differing site condition claim with examples, 3. Underlying philosophies (general applicable principles), 4. Concerns, perspectives, privileges, responsibilities of the parties, 5. Essentials in the presentation of technical elements of a differing site condition

claim, 6. Essentials in the review of technical elements of differing site condition claim, 7. Case histories, 8. Dealing with parties, and 9. Exercises.

Case Histories The case histories used in this work have been selected as examples to illustrate points, concepts, and to reveal the simplicity of the philosophy presented. All cases will deal with subsurface excavation, most with excavation for the installation of utilities, drilling, micro-tunneling, trenching, tunneling, and dredging. These linear or nearly linear types of excavation lend themselves to straightforward and simple analyses of construction performance. The same principles and analyses can be applied to other projects, perhaps with a little more effort.




Exercises Exercises are included in one of the sections of the book to illustrate how crucial the actual hands-on practice is in the development of experience, attitudes, and resolution. The exercises are best carried out by teams composed of individuals having experience as owners, engineers, contractors, inspectors, and attorneys, etc. The reason for this mix is so that in working together, you begin to experience and learn a point of observation different from your normal day-to-day perspective and the requirement to conclude, at least within the team, to a common assessment. The exercises are intended to generate an experience of the concerns, processes, and emotions associated with a position different from your own. Each team shall be:

1. Provided with data from an actual case history, 2. Asked to establish and prepare a presentation of a DSC claim for entitlement,

and 3. Provided with a DSC claim presentation for review.

There is no right or wrong, just effective or ineffective.

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2. FUNDAMENTAL PERSPECTIVES, CONCERNS, PRIVILEGES, AND RESPONSIBILITIES

Owner The owner has to communicate a desire for the construction of a facility, with associated conditions, and with specific requirements, to a series of professionals, who have the task of coordinating their efforts in developing plans and contract specifications between the owner and the lowest bidding contractor. The owner is interested in:

1. Having a completed facility which will perform its intended function, 2. At the lowest possible cost, 3. Within a strict budget, 4. With the least amount of, and 5. On schedule.

In cases where the engineer is the owner, the "engineer's" concern is coincident with those of the owner. When the engineer is apart from the owner, priorities exist which may include the corporate organization, economy, and liability.

Desire for a Working Facility The need for the facility can obviously be satisfied in almost any instance. However, other limitations, such as cost and time to complete must be considered and satisfied. Tight budgetary and time constraints truly test the ingenuity of engineering companies and their ability to provide design services, how well they can provide and define anticipated conditions, design the most economical facility, and reduce the risks and possible cost overruns. It is the owner that takes the inherent risk of whether the project is built on schedule, for the available budget, and with the expected quality.

Cost Considerations Public owners that have allocated specific and limited funds to a project find themselves in difficult situations when cost overruns occur. Such an underlying atmosphere generally forces the owner to seek protection in harsh contract language that often sets the stage for adversary relationships, and makes it very difficult for parties to come to simple and equitable resolutions. This problem may already be compounded by a bare site investigation program, paltry data presentation, and non-existing professional interpretation to provide easily understood anticipated conditions. It is not uncommon to find those government owners to have considerable reluctance in spending more than a minimum for exploration. Owners are generally recalcitrant about




spending funds for exploration, primarily because tangible benefits have not always been illustrated and realized. They find it hard to see the benefits for performing more than a couple of borings to show they adhered to industry standards. Experience has shown that even extensive, costly exploration programs, have not prevented cost overruns, and other difficulties associated with geotechnical conditions. It cannot be a foregone conclusion that the cost/benefit of exploration programs has been as rewarding as possible. There are alternatives. “Costly” exploration is not necessarily consistent with adequate exploration, no more than “economical” exploration may be consistent with inadequate exploration. Exploration need not be expensive and can be made much more effective simply by:

1. authoritative critical thinking, 2. reasonable professional interpretation, and 3. Quantitative and graphic presentation.

The owner/engineer must consider the cost/benefits of:

1. Various levels of exploration (mechanical and intellectual), 2. Professional interpretation of exploratory data (generally minimal and

inadequate), 3. Presentation of geotechnical data (generally poor to barely acceptable), and 4. Use of exculpatory clauses (generally do not hold up).

Saving on exploration and interpretation has generally been associated with higher risk and project costs.

Schedule Considerations Rigorous time schedules have been necessary on some projects in crucial urban locations where projects must be completed within less than typical construction time frames. Additional unique factors include underground construction as being the only choice due to population density. Delays often have serious impact on other portions of a project, local businesses, and the financial well being of the owner. Delays usually have more of an impact with smaller municipalities and threaten the well being of neighborhoods through which con-struction is carried out. Case histories of major delays having destroyed neighborhoods exist. During construction, the owner's representative, is responsible for assuring all contract conditions are fulfilled. That includes maintaining records adequate to fully document all events related to time and space. It is also the responsibility of the owner/engineer to perform timely investigation of differing site conditions. Timely investigation and resolution can prevent such damaging delays.




Owners such as the US Bureau of Reclamation, US Army Corps of Engineers, Washington Metropolitan Area Transit Authority, and Defence Construction Canada, have been known to retain independent or joint outside expertise to review claims submitted to them. The advantage is that an independent expert, especially those retained jointly by both parties, can be more detached from the site investigation, encountered conditions, encountered performance, impact, and the contractor's loss, while the decision is retained by the owner. The design engineer cannot be perceived to be unbiased when encountered conditions are claimed to be different from those portrayed by the engineer's site investigation. Timely resolution of these claims can and has prevented major ruinous delays.

Risk Underground construction is inherently associated with risk. The owner attempts to minimize his risk through language in the contract documents. Consequently, the owner has the upper hand since he is the party who generates the contract documents. Public officials consider a harsh contract with broad exculpatory clauses their only protection against the contractor, who is often viewed as the enemy. Such contracts and exculpatory clauses have generally been ineffective, produced mistrust, generated higher priced construction, resulted in substantial delays, and have generally been detrimental to the utilization of underground space. The degree of risk is directly related to the contractor's perception of anticipated conditions and his degree of certainty. The presentation of borings, boring logs, test results, and broad exculpatory narratives is no longer considered state-of-the-art or even acceptable. Risk is related to how well anticipated conditions and '"ground response" is defined when it is disturbed through construction processes. Exploration merely defines characteristics of the material and not the behavior of the material during construction. The return on investment of costlier exploration may not be realized unless progressive principles and techniques are utilized to present data specifically designed to impart quantitative perception of "ground response" for construction estimating. It is the engineer's responsibility to illustrate effectively to the client (owner) the relationship between cost and benefit of site investigations, interpretation, and contract terms to address unanticipated conditions and risk, and the benefits of equitable allocation of risk. There are countless underground projects where risk, by design, can be reduced and limited. However, this can only be accomplished in the initial stages of project development with the initiative and support of the owner. The use of Boards of Consultants was one such method. However, boards are used less frequently than in the past. Perhaps, some false complacency or "not invented here" attitudes regarding




site investigation, engineering design, and project construction may be responsible for the disfavor of using such boards and consultants. In summary, for an owner, risk can be reduced at a price. A price can be reduced by accepting risk. Engineer The primary objective of any business enterprise is to make a profit and it is unrealistic to assume that an engineering company is any different. A primary profit motive may relegate the best interests of the owner to secondary priority. On several projects, consultants to the owner and boards of consultants have been successful in implementing major conceptual, design, and construction changes that have resulted in major time and cost savings and reduction of risk. Engineering companies are generally sought to provide services during various stages of a project, namely to establish feasibility for basic design, exploration, final design, tendering, and construction. At each stage the associations, objectives, and responsibilities vary. Project site investigations have the greatest influence on the occurrence of differing site conditions. For that reason, the subject of exploration will be considered separately.

Project Feasibility Stage Explorations for feasibility usually precede project design, while exploration for design and construction are for the most part, concurrent. Exploration for feasibility may not require field work and may be completely satisfied by study of already available site conditions either from published geological materials (in remote areas), from nearby experience and archives (in urban areas), or a combination of both. The purpose of a feasibility study is to prepare a preliminary evaluation consisting of:

1. Site Investigation - preliminary "armchair geology" exploration and experience,

2. Feasibility of Construction 3. Conceptual Design (general alignments, anticipated construction methods,

impact), 4. Preliminary Cost Estimates (for budgetary purposes), 5. Impact and Planning (on community), 6. Evaluation of Alternatives 7. Cost Estimates of Alternatives, 8. Evaluation of Schedules.




Preliminary studies will set a project course which will set the risk, impact, possible delays, opposition, unworkable and unnecessarily expensive and disastrous alternatives. The feasibility study is pivotal to project realization. Utilization of specialized consultants by the owner is essential and crucial at this early stage of the project. Fundamental recommendations at this stage of a project have had substantial cost benefits (as much as 20-30% reduction of total cost), incalculable elimination of risk, and benefits that make project approval a reality. There are countless cases where feasibility studies concluded projects to be impractical. It was not until a fresh look from a new perspective, that project feasibility's were re-established. These sources for preliminary site assessment are important. Failure to investigate pre-existing construction experience in local geology has been the cause of many difficulties. However, there is no "punch list" that could ever replace experience; competent understanding of all conditions that impact a project, or rigorous analytical thinking. This is where the experienced expert is required. It has been our experience that site investigations too often follow the misconceptions formed early during project development. It has become apparent that attempting to solve problems within pre-existing set of distinctions are unlikely to open new approaches. Making observations with new distinctions, the problem itself is restructured.

Design Stage It is during this stage that the design is finalized. Design will have a lasting impact on construction methods, duration, and cost, which are intimately intertwined. Project design is based on specific requirements, the ability to construct the structure within available budgets, and within available time. In other words, design must reflect geological conditions, constructability, and constraints imposed by costs, time, and the site. Geology must be considered the independent variable, while design and construction should be treated as the dependent variables. Consequently, the importance of geology and geotechnical properties of the site become much more apparent and must be reflected in the selection of exploration, design, construction, and even what is included in the contract documents. Geology pre-exists design and construction and cannot be blamed for consequences of inadequate investigations, inappropriate design, or ineffective construction intervention (techniques).




Site Investigation The objectives of an exploration program are to satisfy the particular needs of parties involved, as follows:

1. The owner's needs: to have design and construction at the lowest cost, within schedule, within budget, of high quality, and while minimizing risk,

2. The engineer's needs: to have the necessary information to permit the selection

of the optimum location at the lowest cost considering:

a. Design requirements, b. Selection of general or alternative construction methods, c. Preparation of cost estimate, d. Preparation of a bill of quantities, and e. Preparation of contract documents;

3. The contractor's needs: to permit the selection of the most appropriate and cost

effective equipment and construction methods based on the average and the most adverse anticipated conditions. In addition, a contractor must estimate progress and costs related to excavation, stabilization, support, lining, and any potential problems.

There is seldom a complaint that exploratory data was inadequate for design requirements, however, for construction, the opposite is generally true. The needs of the contractor are much more crucial because variations in geotechnical conditions have a much greater impact on construction than on feasibility or design. The most common failure of pre-bid data is providing adequate quantitative data directly usable to develop a construction estimate. It is difficult if not impossible, at least without wild speculation, to use qualitative or limited data to prepare a construction estimate. Exploration, presentation of geotechnical data, and the interpretation of that data are rarely specific or sensitive enough to be useful for direct and quantitative application in the preparation of a construction estimate or establishing day-to-day construction procedures. Many owners and engineers will disagree with this statement, however, the preparation of many "quantitative" pre-bid geotechnical evaluations, have often been frustrated in trying to extract the kind of data that is quantitative, site representative, and reliable. It was found to be difficult to explain to a design engineer, the process of interpreting geotechnical conditions for a construction estimator, unless they have had their livelihood depend on it. Actual construction experience in estimating and day to day on-site field training should be required of engineers that design projects in natural materials and that require underground construction techniques.




Geotechnical Data Reports Owners and engineers have been reluctant to present more than the bare minimum of geotechnical data necessary for design based on advice of their attorneys. They have been advised to avoid providing interpretations at all costs. In recent years, the engineer has been increasingly vulnerable and the courts have often found on behalf of the contractor, even against engineers. However, detailed geotechnical information has served to decrease the uncertainties to which excavation is uniquely sensitive. The magnitude and nature of an exploratory program should be designed on the basis of the:

1. Importance (use & cost) of the project to be constructed, 2. Nature of site geology, 3. Sensitivity to construction methods and equipment, and 4. Evolution of exploration with project design to suit geotechnical conditions.

There is no standard scope of an exploration program, rather, the sophistication varies with the complexity of the project and its geology, method of construction, funds available, and parties involved. There are, however, alternatives to providing only the bare minimum or interpretations that may create liability for unanticipated conditions.

Geotechnical Interpretive Reports Interpretation of the site investigation data is required to make design recommendations at the earliest development of the project concepts and during selection of various design choices. These interpretations address design considerations for the most part while dealing with construction issues only so much as they affect design considerations and selection of general construction methods.

Presentation of Exploration Data If the owner and engineer wish to avoid providing the contractor with interpretations of anticipated geotechnical conditions and behavior, at all costs, it is still possible to present geotechnical data that are conducive in producing:

1. Straightforward simple interpretations, 2. Quantitative interpretations, and 3. Interpretations that fall within limited and/or narrow ranges.

Presentation of factual data during bidding permits and promotes a wide variety of interpretations and optimism by individuals least familiar with the project and its geology and least qualified to interpret that data. Practices and techniques have been




developed for representing geotechnical data specifically for use in preparing construction estimates. The presentations:

1. Are factual and without interpretations, 2. Have produced greater confidence among contractors in submitting bids, and 3. Presented a picture, which is likely to be interpreted within a narrow range by all

bidders. Presentations of anticipated conditions to be used for preparing construction estimates should provide:

1. The full range of anticipated conditions, 2. Average anticipated geotechnical conditions, and 3. The most adverse geotechnical conditions that are expected to impact

construction. The range, average, and most adverse conditions should be defined quantitatively, pre-ferably graphically, and throughout the project area. Too often, remotely located borings, samples, or test results are provided for a sizable area without an indication of their applicability to the large expanse of the site between borings. A contractor can do no more than average results from two such sources. Alternative or undocumented interpretations, projections, or utilization of site data, often should be documented, by the engineer (and naturally by the contractor as well). In hindsight, it is in the best interests of the owner to have the engineer provide the most expressive representation of geotechnical conditions and construction behavior. The best possible presentation of "factual" data will:

1. Require less interpretation by bidders who may be less qualified than the engineer and

2. Permit only a narrow variation in interpretation among bidders.

Simply put, the more obvious the data, the less interpretation required and the narrower the range of interpretations and therefore the bids. The Range of Conditions. The range of geological conditions is the basis for design of construction methods, selection of equipment, and preparation of the construction estimate. The entire scheme (e.g. - dewatering, pumping, discharge facilities, stabilization, support, ventilation for gassy excavation, muck system, crew sizes, etc.) are designed and selected to deal with the range of anticipated conditions while maintaining consistently high productivity. Average Conditions. Average conditions are used to calculate average performance (penetration, utilization, tool consumption, and daily progress rate, etc.). Average conditions are the basis for sizing or specifying the capabilities of the means, the methods, and the equipment. This average performance is the basis upon which the




estimate is prepared, while also including the performance in the extreme range of conditions. Average conditions may be defined by material (soil or rock) intact properties, mass properties (presence and characteristics of joints, faults, shears, weathering, alteration, RQD, stress conditions), permeability, and mass behavior (overbreak, squeezing, swelling, slaking, water inflow, and gas infiltration). They all intimately influence excavation stability and support requirements. Most Adverse Conditions. Adverse geological conditions are those that are worse than the average anticipated conditions. These conditions must be evaluated carefully since:

1. Their spatial extent and 2. Degree of severity

will significantly affect construction performance and may alter feasibility or even constructability. The choice of how to deal with the most adverse conditions will depend on the particular contractor. The choice may be to slowly struggle through such conditions without changing means & methods, or the alternative, to change means & methods and maintain a high rate of progress. The choice will depend on the contractor, his experience, and his perceived solution to the least risky and most economical approach. Adverse conditions may consist of material index properties as well as mass properties. More difficult or more extensive difficult conditions than anticipated are effectively an adverse condition. Both will decrease productivity and increase construction costs and duration. The construction scheme is normally designed to cope with the most adverse conditions with some reduced productivity while producing no major consequences or requiring a major change in methods, equipment, or major delay. Exculpatory clauses have had mixed results. Boilerplate disclaimers have not been effective in negating positive representations of material fact (moist sand) and yet, other courts have found disclaimers clear, unambiguous, and have upheld them. Soil disclaimers of "no representation" based on site investigations being made for the purposes of design and not for preparing a construction estimate have had various interpretations as well. It is generally understood that the owner has a duty to disclose all available information and material facts. The courts have generally agreed. Unless the contractor’s choice of means and methods cannot be justified from the geotechnical information available, it behooves the contractor’s to obtain additional data.




Geotechnical Baseline Reports The competitive bidding environment is conducive to optimism, particularly when information to the contrary is lacking. Therefore, optimism may lead to insupportable differing site condition claims, which can be prevented by leaving little to the interpretation of the contractor. An ASCE Publication (1997) has made recommendations for the preparation of Geotechnical Baseline Reports (GBR), which is to be considered the sole baseline and basis for differing site condition claims. The GBR, unlike geotechnical interpretive reports, directly addresses practical geotechnical and ground characterizations affecting construction issues. Most site exploration programs often leave a great deal to be desired in their applicability to establishing purely quantitative anticipated conditions, behavior of natural materials, excavation stability, and constructability. Even projects that provide more than an average amount of site data may not provide the more rigorous interpretation and presentation needed for direct applicability to a construction estimate of:

1. Quantities of various geological materials, 2. Material behavior, 3. Progress rates, 4. Selecting reliable estimates of ground support, 5. Cost of expendable materials and supplies, 6. Equipment wear and maintenance, 7. Construction costs.

Exploration data for construction decisions have to be more explicit and require a great deal more interpretation than for design. Unfortunately, this is not always considered and the needs of construction specifically addressed. Factual data available at bid time for major projects is so voluminous that it is impossible to fully utilize within the allotted time. Theoretically, it is possible to require each and every bidder to engage someone to interpret available data. The result will likely be widely varying, and undesirable. Professional geotechnical interpretation by the owner or his engineer (made available at bidding time), should define clear and reasonable anticipated conditions, methods of evaluating encountered conditions, and methods of establishing legitimate differing site conditions, should they occur. Providing professional interpretation of anticipated conditions and indications of anticipated ground responses are considered essential to assure that all contractors are bidding the same conditions and have reasonable expectations. It becomes clear that a great deal of the responsibility rests on the owner and his engineer. This is appropriate because they are involved from the inception, for the longest period of time, and throughout the project. They are most qualified to produce the geotechnical reports and contract documents, and are most familiar with all relevant conditions. The contractor is generally involved only during the bidding period that may be as short as 1-2 months.




The responsibility of organization and development of exploration for the design and construction of a project should belong to an individual having the qualifications that include knowledge of general geology, intimate knowledge of engineering geology, familiarity with geotechnical engineering associated with design of a structure, intimate familiarity with construction equipment and methods, and an understanding of costs associated with construction methods. In the case of underground construction, the responsible geotechnical professional should have an effective background of experience in that field.

Construction Stage The site engineer's prime responsibility is to assure conformance to the construction contract. In this capacity, the engineer will document site activities and maintain records. When notice by the contractor is given that a differing site condition is suspected, the engineer has the opportunity to investigate them. However, collection of data only after such notice has been given, after the project has been underway for some time, is likely to be inadequate in providing the necessary data to define fully the encountered conditions and performance. For instance, early project inefficiencies and mechanical difficulties, in some instances, have been responsible for substandard performance rather than the claimed conditions. Such circumstance can only be investigated with records that cover the entire construction period. Additional discussion of record keeping will be found under a separate heading on the subject. Contractor The contractor faces many and various risks (inflation, bad weather, strikes, equipment and labor problems, shortages of materials, accidents, and unforeseen site conditions). Ultimately, the contractor faces the loss of money, loss of business, and bankruptcy of the company. In the face of harsh contracts, contractors are often discouraged from bidding. Ambiguous language and exculpatory clauses are thought to be protective of the owner, result in conflict, and the courts have generally found in favor of the contractor.

Contract Provisions Most contractors tend to jump into the contract plans and specifications and may not adequately consider the importance and impact of the general provisions. This can have devastating consequences. The three major standards that are used as a basis for writing contracts are:

1. Federal Government Standard Documents (FGSD),




2. Engineers Joint Contract Documents Committee (EJCDC), and 3. American Institute of Architects (AIA)

Each of these deals differently with:

1. Time extensions, 2. Escalation clauses, 3. Changed conditions, 4. Variation in quantities, 5. Extras and changes in the work, 6. Exculpatory language, 7. Disputes, 8. Plans and specifications, and 9. Other contract cautions.

Each varies from the other with variations in language having notable consequences. Such variations, particularly if one is unfamiliar with their implications, should be understood before bidding a construction project.

Site Investigations When the engineer's exploration, design, and contract documents have been completed, the project is bid. At this stage of the project, a number of contractors will attempt to prepare the lowest (reasonable) bid. A contractor preparing a bid has some very simple questions to answer:

What, how much, where, and when? The quantitative answers to these questions form the basis of his estimate and bid. How does he get there? Within the period available, the contractor should utilize reasonably available data (reports, logs, samples, test results, local experience, site inspection, examination of work area, walking of the alignment) that can reasonably provide insight and knowledge of anticipated conditions. He should avail himself of all resources, such as documentation, even when merely making reasonable assumptions. Furthermore, use of any of the above should be documented in writing. The intensity of the contractor's investigation, however, will eventually be judged within the context of available time during bidding. The contractor's interpretations are not expected to be as sophisticated as those of the engineer since the contractor is not licensed as an engineer. It is hardly possible to expect the contractor, in the short period available for preparation of an estimate, to accomplish much more than simple




interpretation of available data. After all, the engineer's project associations may span several years. The contractor's interpretation of site data cannot be expected to be as sophisticated as that of the engineers, particularly within the time constraints of the bid period. An attorney, representing engineers, expressed his opinion as follows:

"Soil testing is expensive and the data necessitates interpretation by a professional. Because the answers to subsurface questions are so indefinite, the soils engineer is usually excluded from the design team so the architect is not liable for any negligence."

It is reasonable to expect available exploration data should be in a format that can be interpreted in the available time by the level of expertise normally within the contractor's organization in the particular industry. For example, normally, it is considered inappropriate to provide raw geophysical field data to be interpreted by a contractor. Typically, a contractor is not required to have in-house or retained geotechnical expertise. However, he is expected to have reasonable knowledge and understanding of geotechnical principles as related to construction. The time and effort taken to consider and interpret available site data should be consistent with the bidding period. It is unreasonable for the contractor to develop analyses anywhere near as sophisticated as those developed by the engineer. The contractor is licensed to construct, the engineer is licensed to explore and design. The contractor, when developing anticipated conditions and excavation performance should leave a clear trail that anyone can reproduce and follow. It is essential that the contractor document and demonstrate a reliance on site investigation data if he intends to depend on the protection of the differing site condition clauses. Essentially, the estimate should be prepared like a high school algebra problem, including documentation of the following:

1. What is used, given, or provided (with specific references to the source of the information, reports, page numbers, etc.) particularly in terms of average, range, and most adverse conditions,

2. Information used by the contractor to prepare an estimate, 3. All assumptions, past experience, or relationships relied upon in the development

of anticipated performance, 4. Basis of selection of construction methods & equipment, 5. Alternatives, basis of selection, reason for non-selection, 6. Questions and answers to: / What? / How much? / Where? / When?, 7. Disparities, resolutions, and compromises between joint venture partners, and 8. Conclusions.

The technique of presenting site investigation data has more of an impact than its quantity or quality. Presentation will have considerable consequences on how well it will be understood, interpreted, and utilized. An effective presentation will produce a




very narrow interpretation and similarly narrow set of bids. However, the contractor cannot be held responsible for this, especially if not done by the engineer. The engineer and owner should be consulted if any questions arise with regard to site conditions and available data. Should inconsistencies arise, they are best resolved before bid. If reasonably accessible, the contractor may benefit from local experience. It is possible to visit nearby projects, examine pay estimates of adjacent construction work, if made available. The site / alignment should be traversed by whatever means necessary. Local outcrops, road cuts, quarries, and foundation excavations, may be examined, if applicable. However, these recommendations can only be considered with respect to available time, site specific, and reasonability. It is reasonable, for example, that specific and/or quantitative data supersedes general and/or qualitative data, and site-specific data supersedes non-site-specific data.

Reliance Very simply, the contractor must

1. Have relied, 2. Provide evidence, and 3. Illustrate

that he has relied on the contract and associated documents for the establishment of anticipated conditions and construction performance. On occasion, entitlement for a differing site condition claim has failed on this issue alone, when the contractor could not show how they arrived at anticipated construction performance based on conditions indicated in the contract documents.

Notice When a differing site condition is suspected, one of the most essential and explicit requirements specifies that the contractor should give notice. The intent of notice is to permit the owner/engineer to investigate suspected conditions in a timely fashion. Courts have been fairly strict regarding notice, while, Boards (of Contract Appeals) have not always strictly adhered to notice requirements. There is a case pending of a contractor making a claim for overbreak after the concrete lining had already been installed? Although, the owner could not specifically investigate the contractor's claim, he did have records that could be used to scrutinize claimed overbreak at some locations.




Mitigating Impact The duty to mitigate the impact of differing site conditions is a general contract principle based in common law. Contractors are generally reluctant to spend money in addition to the already escalating costs associated with unanticipated conditions, particularly when encountering resistance from the owner/engineer. Consequently, it is more common for the contractor to be perceived as failing to mitigate. In one instance, the contractor was able to mitigate the impact of differing site conditions by increasing the crew size to cope with unanticipated support requirements. The mitigation efforts were so effective that production exceeded anticipated progress. The cost of mitigation, however, was substantial and the contractor was entitled to use the improved performance as the baseline for calculating his DSC costs. Commonly, the contractor when effective in demonstrating additional costs to mitigate unanticipated conditions is appropriately compensated. Record Keeping Without records and passage of time memories fade, verbal agreements and details are not easily recalled, and the stage is set for potential disputes and claims. Conscientiously kept records are essential in the prevention and resolution of differing site conditions and may well serve to keep the differences out of the courtroom. Documentation should be maintained independent of any possible dispute. The usefulness and value of construction records go far beyond mere disputes. They can form the basis of well-grounded competitive bidding for future project estimates. It is good practice for owner, engineer, and contractor to maintain records that document encountered conditions and construction performance throughout the project duration. It seems wasteful, however, to have to maintain two complete sets of records by both the engineer and contractor. Record sharing has been successful in reducing the resources spent on this effort. For example, records of encountered conditions have been maintained by the resident staff, construction performance records have been provided by the contractor, while other records, unique to each party, have been maintained independently.

Dimensions of Time and Space Records must identify all aspects of construction in the dimensions of time and space. In other words, records must be able to locate all conditions, events, equipment, labor, etc., within a framework of time and space.




Responsibilities of the Owner, Engineer, and Contractor

The responsibilities of the owner, engineer, and contractor are similar and consistent. It is the owner/engineer's responsibility to maintain the records that will permit investigation, analysis, and resolution of any disputes that may arise. The contractor's responsibility during construction is to conform to contract specifications and requirements. The requirements of the differing site condition clause require that the contractor show the difference in cost (time, performance, labor, resources, duration, supplies, materials, equipment, etc.) Proper record keeping is essential to provide the necessary foundation for investigating, establishing, and presenting a differing site condition claim. Each type of construction, project, or contractor keeps unique records to document activities, expenditures, and utilization of resources. Shortcomings in record keeping do not become obvious until it is too late. At the same time, it is not possible to design or provide standard forms that will deal with all cases adequately or even appropriately. The following summarize good practice in developing appropriate and working construction records:

1. Utilize forms from previous and similar construction, 2. Modify and establish the format early during construction, 3. Quantify all possible descriptions, method of measurement, and 4. Do not use graphic method of recording (e.g. - time bar charts), use quantitative

data.

Records The typical type of records to be collected and maintained can best be summarized by the various stages of construction, namely during pre-bid, bid, pre-notice to proceed, contract, and construction.

1. Pre-bid (invitation to bid, site visit notes, photographs, minutes of pre-bid meetings, proposed schedules, estimates with worksheets, project log, addenda, logs of telephone conversations),

2. Bid (all papers, calculations, quantity takeoffs, sub and supplier quotes,

estimates of productivity, proposed schedule, all assumptions),

3. Pre-contract (minutes of all meetings, record of job schedules, record of changes),




4. Contract (original contract documents),

5. Construction (minutes of pre-construction conference, copies of job schedules, job diaries, photographs with notes and typed notes initialed and dated, daily records, visitors, weather, materials delivered, trades working, names of all workers),

Pre-bid Pre-bid records should include:

1. Invitation to bid, 2. Site visit notes, 3. Photographs, 4. Minutes of pre-bid meetings, 5. Proposed schedules, 6. Estimates with worksheets, 7. Project log, 8. Addenda, and 9. Logs of telephone conversations.

Bid Records prepared and maintained during the bidding period should include:

1. All papers, 2. Calculations, 3. Quantity takeoffs, 4. Sub and supplier quotes, 5. Estimates of productivity, 6. Proposed schedule, and 7. All assumptions.

Pre-Notice to Proceed Pre-notice-to-proceed records should include:

1. Minutes of all meetings, 2. Record of job schedules, and 3. Record of changes.




Contract All contract documents should be maintained as follows:

1. Original contract documents, 2. All addenda, and 3. Conformed set of contract documents.

Construction Maintained project duration records should include:

1. Minutes of all meetings, 2. Copies of job schedules, 3. Job diaries, 4. Photographs with notes and typed notes initialed and dated, 5. Shift and daily records, 6. Visitors, 7. Weather, 8. Materials delivered, 9. Trades working, and 10. Names of all workers.

The typical list of supportive documents as a basis for claims includes:

1. Shop Drawings, 2. Job Schedules, 3. Owner's Records, 4. Correspondence, 5. Change Order Files, 6. Shift or Daily Reports, 7. Payment Requisitions, 8. Minutes of All Meetings, 9. Field Reports, 10. Weather, 11. Material and Equipment Records, 12. Accident Records, 13. Delay Records, 14. Subcontractors, and 15. Overhead.

Full documentation should fully define all time and space associated with the construction envelope and answer the following questions:

Who, What, How much, Where, and When?




Record keeping should be quantitative and based on forms that:

1. Are simple, 2. Are few in number, 3. Cover major quantitative construction performance in time (date, hour,

minutes) and space (station, coordinates, depth, etc.), a. Construction progress, b. Expenditure of supplies, c. Resources (labor, equipment),

4. Reflect factual encountered conditions (excavation logs, face sketches, quantitative estimates, photos, videos; observations and reports also should report when there is no forward progress to document deteriorating conditions),

5. Allow future development of causal relationships, 6. Can be used to demonstrate that there are no causes other than differing site

conditions that responsible for the loss of construction performance Documentation should always be specific, quantitative, and reflect conditions (material properties), behavior (stability, overbreak, water inflow, swelling, slacking), and construction performance (support installed, grouting progress, muck removal, etc.), which normally are associated with differing site conditions. For obvious reasons, "discovery" being one, every piece of paper is likely to be accessible and will likely become a part of the legal proceedings. The records should stick to observable and measurable events and variables. Opinions should be kept to a minimum and used only when necessary. Wisecracks and personal remarks should be avoided. Examples of various construction reporting forms are illustrated in the appendices.




3. ELEMENTS OF A DIFFERING SITE CONDITION The Differing Site Condition Clause Differing Site Conditions are based on the DSC Clauses included in most con-struction contracts; a typical example (from the US Bureau of Reclamation) is as follows:

Differing Site Conditions (a) The Contractor shall promptly, and before such conditions are disturbed, notify the Contracting Officer in writing of: (1) Subsurface or latent physical conditions at the site differing materially from those indicated in this contract, or (2) unknown physical conditions at the site, of an unusual nature, differing materially from those ordinarily encountered and generally recognized as inhering in work of the character provided for in this contract. The Contracting Officer shall promptly investigate the conditions, and if he finds that such conditions do materially so differ and cause an increase or decrease in the Contractor's cost of, or the time required for, performance of any part of the work under this contract, whether or not changed as a result of such conditions, an equitable adjustment shall be made and the contract modified in writing accordingly. (b) No claim of the Contractor under this clause shall be allowed unless the Contractor has given the notice required in (a) above; provided, however, the time prescribed therefore may be extended by the Government. (c) No claim by the Contractor for an equitable adjustment hereunder shall be allowed if asserted after final payment under this contract.

Type 1 relies on express or implied representation. Thus, if the contract documents are silent regarding such conditions, strictly speaking, there can be no recovery under a Type 1 conditions clause. A Type 1 DSC deals with intentional or unintentional misrepresentation of site conditions. In order to recover for this type of differing site condition, a contractor must generally show four things:

1. The actual encountered conditions, 2. The conditions indicated by the plans, specifications, and other contract

documents,




3. The variance, and 4. Proper notice.

Type 2 requires a greater burden of proof to establish reasonableness. These claims do not involve contract indications vs. actual conditions. Rather, they involve comparison of actual conditions with what the contractor could reasonably have anticipated based on generally recognized as inhering in work of the character provided for in this contract. A contractor may recover damages equal to the difference between the fair and reasonable cost of performing the work if the conditions had been as warranted (including costs of labor, materials, claimed damage, overhead, damage by delay, etc.). For the most part, knowing the details of the law is not crucial when the contractor prepares evidence for site condition claims. These details are also not needed for the engineer to review the technical merits (entitlement) of the claim. However, one should have an understanding and guidance of an attorney to assure conformance to local laws and intent of the contract. An example of a decision by the Court of Appeals summarizes the requirements as follows:

1. The contract documents must have an affirmatively indicated or represented the subsurface conditions, which form the basis of the plaintiff's claim.

2. The contractor must have acted reasonably in interpreting the contract documents.

3. The indications must have induced reasonable reliance by the contractor that the subsurface conditions were more favorable than those actually encountered.

4. The subsurface conditions actually encountered within the contract site area must have differed materially from the subsurface conditions indicated in the same contract area.

5. The actual subsurface conditions encountered must have been reasonably unforeseeable.

The contractor must show the claimed excess costs were solely attributable to the materially different subsurface conditions within the contract site. The court's finding was:

1. The contract did not affirmatively indicate the specific quantities of the various subsurface materials but only indicated the types of subsurface materials and the total volume of all materials to be removed. Contractor’s estimate of the quantities of specific materials, which it obtained by use of interpolation, ex-trapolation, and the Uniform Soils Classification System, does not constitute contract indications.




2. Since most of the borings were taken from the river banks rather than the channel to be dredged and since the Contractor did not adjust its bid to account for the risk inherent to its estimate, the Contractor did not reasonably interpret and rely upon the contract indications.

3. (same as #2) 4. The Contractor failed to establish that the actual subsurface conditions

differed from the alleged contract indications since the proof consisted of inaccurate data (measured by the "eyeball" method) and data from dredged materials outside of the contract area.

5. It was reasonably foreseeable that the quantity of gravel and Eutaw would

exceed the Contractor’s estimates but the contractor made a superficial pre-bid site investigation.

6. The Contractor failed to show its damages were due solely to the alleged

differing site conditions. That is, the Contractor failed to show the delays were not concurrently caused by its own faults, e.g., poorly trained employees and excessive equipment failure.

The foregoing elements are primarily founded in law and the technical elements presented are consistent with such judicial review. List of Technical Elements Based on a number of differing site condition claims, presentations, reviews, and decisions, a distinction of technical elements or requirements have been developed that can be used by the contractor as a framework when preparing the differing site conditions claims. The engineer would then have the same guidelines by which to review the submitted claim. Both parties can then have a common set of principles or specific points to use while resolving any impasse. The technical elements or principles of a differing site condition claim may be summarized as follows:

1. There must be a difference between reasonable anticipated and verifiable encountered conditions,

2. There has to be a difference between reasonable anticipated and verifiable

encountered construction performance,

3. A cause and effect relationship must be demonstrable between the differences in conditions and construction performance,




4. There must be a demonstrable and material impact on construction duration or costs,

5. All contract conditions must be fulfilled, and

6. Other factors cannot have caused the difference between anticipated and

encountered performance. Aside from the presentation and analysis of claims, these principles also serve as a context for design of project exploration, geotechnical investigations, presentation of geotechnical data, interpretive evaluation, and the geotechnical baseline report. These principles also serve to persuade the contractor of the importance of documentation at bid time as well as maintaining construction records throughout project duration. The importance of:

1. Pertinent exploration, 2. Crucial presentation of geotechnical conditions, 3. Representation of:

a. Average conditions, b. Range of conditions, and c. The most adverse conditions, and

4. Reasonable interpretation, becomes apparent to the owner/engineer prior to the bidding period. For the contractor it is crucial to:

1. Document data utilized in preparing his estimate and any assumptions, 2. Prepare and document all interpretations made during preparation of the

estimate, and 3. Maintain simple, complete, and impeccable records (that can be cross-

referenced) during construction. The contractor benefits from these guidelines as a reminder, at the time of bid preparation, to document all data used, assumptions made, and the basis of interpretations. In addition, the contractor has a checklist for evaluating and fulfilling the requirements of a differing site condition claim during construction before they become problems or sources of controversy with the resident engineer. The immediate cause, effect, and impact can then be assessed properly. Examples of compliance and non-compliance of each technical element will be illustrated with actual case histories. When a contractor's presentation adheres to these principles and fulfills its requirements, he will:




1. Build a strong case for his claim, 2. Provide the engineer a reassurance that all elements have been fulfilled, and 3. Satisfy the checklist for reviewing the claim.

In the claim review process, such a checklist guides the owner/engineer for evaluating and checking full compliance to requirements of a differing site condition claim on a technical basis before becoming a source of controversy that entrench parties into adversary positions. The immediate cause, effect, and impact can then be assessed properly. Compliance and non-compliance of each technical element can be tested. An acceptance of these principles by the owner and engineer makes review of claims simpler, more routine, and easier to evaluate. If not all conditions are fulfilled, data that are more specific can be requested or the claim can be denied pending submission of particular evidence. Examples will be illustrated with actual case histories. The discussions of each of these elements have been summarized in tables as a list of suggestions. These lists are exhaustive and it is not intended that the entire list be applied to each case. For the straightforward, simplest, and self-evident cases, only the most fundamental points should be applied. The lists are not intended to be used as an obstacle course, especially by a recalcitrant owner/engineer. The list of suggestions should only be applied by individuals experienced in construction and practical geotechnical issues, preferably by the resident engineer; otherwise, the application of such a list will become an obstacle course. It is also best to separate the issue of entitlement from the issue of quantum so that a review is based solely on technical merit and not influenced by unfounded quantum. Nevertheless, dealing with quantum becomes relevant only when entitlement has been established. Site Conditions The fundamental topic will deal with site conditions, anticipated, encountered, and differ-ences between them. Anticipated conditions are generally provided in contract or associated documents. If they are not, it is necessary for a contractor to develop reasonable anticipated conditions based on normal conditions generally inherent in the type of work. The encountered conditions are more readily determinable, as excavation progresses. However, the encountered condition causing the construction difficulty may not always be readily apparent and may be associated with behavior under construction conditions, rather than inherent properties of the material.

Reasonable Anticipated Conditions




Reasonable anticipated conditions must be indicated, based on information provided in association with the project, or generally known to exist and inherent with the type of work at hand. Nevertheless, the term “reasonably anticipated conditions” raises the following questions:

1. What are reasonable conditions and in what time frame? 2. What is the applicable standard for reasonability (at the time of bid)? 3. What are the responsibilities of the engineer & contractor for interpretation of

geotechnical conditions? 4. What is the level of expertise to which each party (engineer, contractor) can be

held? 5. What "should" or "could" have been done (out of hindsight)?

An example of a presentation of anticipated conditions using uniaxial strengths are provided in Figure 1. The strengths in Figure 1 were averaged in each of the two borings (87-19 and 87-23) available pre-bid, separately before being averaged to provide a project wide applicable average. Since the borings represent rock at a shallow depth and since they are at opposite locations outside the area of construction, this method was considered most appropriate. In other words, it cannot be justified to use the full range of uniaxial strengths in both borings and apply them project wide, especially since the rock lithology varied throughout the site, as did the top of rock, Rock Quality Designation (RQD), and rock fracturing. The average uniaxial strength obtained in this manner is appropriate to use in the contractor's estimate of average drilling rates and cuter costs. Suggestions for presenting anticipated conditions are outlined in Table 1 and a summary of suggestions for reviewing the contractor's presentation of anticipated conditions are provided in Table 2. On a dredging project, for example, Figure 2 illustrates two sources of data from which gravel content can be determined, namely, borings and from the existence of local gravel pits. It also compares the gravel content assumed by the contractor and the average encountered gravel content through the dredged area. Although the borings, on the average indicated about 12% gravel, this would indicate the minimum that could reliably be expected because of the effect of the small diameter borehole to the size of the gravel. Other indications in the area to be dredged consisted of commercial gravel pits, which reflected 50% gravel content. In fact, a mined out gravel pit was to be used as a disposal area. Consequently, the estimate of gravel cannot justifiably ignore the presence of gravel pits in the area to be dredged. Since the successful bidder had never before performed hydraulic dredging, it would have been prudent to ask to see pay estimates and performance records from adjacent projects to determine typical dredging rates in local conditions.




The potential problems were compounded by the fact that the contractor bid the project with a new dredge and actually utilized a 40-year-old dredge that had not been used in nearly a decade.

Credible Encountered Conditions Encountered conditions are susceptible to fewer differences of opinion than anticipated conditions because they are directly and more extensively observable, measurable, recordable, and require little to no interpretation. Nevertheless, well selected sampling locations, standard testing methods, and procedures should be followed. Adherence to standards confirms credibility of data, expedites agreement, and minimizes obstacles toward resolution. Sample selection is usually most prone to challenge from an owner/engineer. Suggestions for presenting encountered conditions are listed in Table 3. Figure 3 summarizes encountered conditions measured in terms of uniaxial strength. Two sets of drilled core and uniaxial tests were obtained by the contractor from two separate drilling programs. Two sets of results were obtained by a consultant hired jointly be the owner and contractor from drilled core and concrete hammer (Schmidt Hammer) measurements. The results are consistent, if one takes into consideration that the contractor's first boring program sought to identify hard rock in areas of slow drilling while the second boring program was designed to sample a wide range of rock strength, including the softer rock areas. The second set was specifically designed to sample soft rock to develop a good empirical cause and effect relationship over as wide a range as possible. The data from four sources can be presented with frequency distribution diagrams, bar charts, or consolidated, representing overall averages and ranges. A review of a DSC should include a reconciliation of records of the site geologists, resident engineer's records of encountered conditions, and checking of all geotechnical data presented by the contractor and underlying the DSC claim. Encountered conditions that are claimed to have affected performance should be scrutinized that, in fact, they have the ability to produce the effects claimed. A summary of suggestions for reviewing a presentation of encountered conditions is provided in Table 4. An indication that differences in conditions are perhaps not demonstrable is a failure to establish reliance on available data or quantitative anticipated conditions based on data available at bid time. For example, a comparison of permeabilities to encountered inflow is suspect because permeability is a measured characteristic of the rock mass,




whereas inflow is a "ground response" as a consequence of excavation. Water inflow is affected by permeabilities, joint characteristics, joint frequency, and water head. Inconsistencies regarding encountered conditions tend to surface when attempts are made to illustrate encountered conditions that are at odds with units or variables of available anticipated condition data. Another indication may be when (anticipated) factual data is compared (or not compared at all) with construction behavior, as an example, anticipated permeability values are compared with actual inflows. Differences of opinion regarding the impact of encountered conditions on construction delays or difficulties should be factually documented by the owner (engineer) and the contractor. These records are essential in establishing or denying a differing site condition claim. It is necessary for a review of encountered conditions to check that performance consequences caused by encountered conditions or by the chosen method, equipment, or execution of the work. Figure 4 illustrates a case of encountered water inflow being less than anticipated. However, even the encountered water flow was suspect. The highest peak inflow measured on 1 Dec was caused by a heavy rainstorm, a stream flowing into a shaft, the shaft connected to an adit, which in turn emptied into the tunnel. This additional flow was measured as tunnel inflow from the rock mass. The peak occurring in February (end of mining) was caused by ice forming in the measuring weir resulting in a higher reading.

Differences between Anticipated & Encountered Conditions Differences between anticipated and encountered conditions, especially if already defined in quantitative and graphical terms should not pose difficulties. A common question is: how much of a difference is significant? In some contracts, differences have been defined as variations on the order of 5-25% in the bill of quantities. However, more realistically, even if the difference is small, it is the monetary impact that will govern in making a claim. Some of the best ways of illustrating differences in conditions are by making the comparisons according to zones along the excavation alignment, as often is done during preparation of the estimate. Such an example is illustrated in Figure 5. Another method is to use high-low graphs that conveniently illustrate the range of values as well as the averages as shown in Figure 6. Illustrations such as Figure 5 and Figure 6, comparing both the full ranges and the averages, can be quite persuasive. Such illustrations leave no doubt that in fact the encountered range as well as the average values have varied from those that were anticipated.




An example where no difference in conditions was found is illustrated in Figure 7. The water inflow into the tunnel did not exceed expectations yet the contractor claimed additional compensation. In addition, some of water inflow peaks were erroneous, as discussed previously. Observation of the data illustrated in Figure 7 suggests some unusual peaks. Good practice would be to investigate their occurrence in time and space, determine the cause of the peaks, and asses the impact on the claim itself. Examination of various reports around the time that these peaks occurred revealed the actual causes and will be discussed later. Suggestions for presenting differences in conditions are provided in Table 5. A summary of suggestions for reviewing the contractor’s presentation of differences in conditions is provided in Table 6. Construction Performance How is construction performance measured? Any measure that has an impact in terms of time and cost can be used as a measuring scale. Some of the common terms utilized fall into the following general classifications:

1. Construction Instantaneous Rate,

a. Drill penetration rate (m/hour) b. TBM penetration rate (m/hour)

2. Equipment Utilization

a. Drill utilization (%) b. TBM utilization (%) c. Dredge utilization (%

3. Equipment Availability (DO NOT USE THIS TERM - its definition and application

is much too inconsistent; relies on interpretation, and obscures underlying facts such as causes of downtime);

4. Construction Advance/Progress Rate (advance rate)

a. Drill hole advance (m/shift, m/day) b. Excavation advance (m/shift, m/day) c. Volumetric advance (cubic meters/shift, cubic meters/day)

5. Tool Wear / Costs




a. Drill bits ($/meter, $/cubic meter) b. TBM cutters ($/meter, $/cubic meter)

6. Equipment Wear / Costs ($/operating hour)

7. Repair & Maintenance

a. Time b. Materials

8. Resources of Materials/Supplies

a. Blasting supplies ($/cubic meter) b. Support elements ($/meter of excavation)

9. Man-Power Resources

10. Construction Efficiency

a. Equipment (equipment hours / unit) b. Manpower (man-hours/meter, man-hours/cubic meter)

Reasonable Anticipated Construction Performance Figure 8 through Figure 10 are relationships that take into account anticipated condi-tions and equipment parameters. Since the empirical relationships are based on experience, they fulfill the requirement of consistency with experience. Figure 8 illustrates a relationship between Total Hardness and tunnel boring machine (TBM) penetration rate. Curves such as this are commonly used to estimate TBM penetration rates and cutter consumption. These relationships have been published while others have been developed internally and are considered proprietary. Nevertheless, if the relationships are based on reliable data, they are legitimate tools for estimating TBM performance. Figure 9 illustrates a graph that cannot be used for a TBM estimate because:

1. The cutter load is not the most important factor affecting penetration and 2. The scatter is much high too confirm any type of correlation (R2 = .02).

Not all relationships are as clearly defined as a simple regression line. For example, estimating drilling rates for percussive drilling equipment is based on comparative assessments against a suite of various rock types from various locations throughout the




world. A good example is the Ingersoll-Rand table for comparative drilling rates. Another example is the Caterpillar chart for rippability illustrated in Figure 10. Suggestions for presenting reasonable anticipated performance are outlined in Table 7. A summary of suggestions for reviewing the contractor's reasonable anticipated performance presentation is provided in Table 8. Any challenges must be substantiated and confirmed by evidence. An investigation is required to determine if there were any quantifiable shortcomings in the equipment, the reasonability of the contractor's assumptions and estimates of performance, etc. On a dredging project the rate of volumetric excavation was theoretically calculated based on general dredge pumping principles without considering the condition of the equipment. The unreasonable anticipated dredge capacity is illustrated in Figure 11. The actual capacity of the dredge in the field in the same combinations of sand and gravel was used to illustrate that the anticipated performance was unreasonable. In other words, the capacity of the dredge to perform was far below what the estimator expected of it. Encountered construction performance is in most cases easily measured and allows for little controversy if accurate records are kept. The source of disagreement regarding construction performance is generally associated with the causative agent of the poor performance.

Verifiable Encountered Construction Performance Suggestions for presenting encountered performance are outlined in Table 9. Figure 12 is an example of verifiable performance. The contractor's records were utilized by the owner to determine actual performance of a hydraulic dredge in various combinations of gravel and sand and to develop the data in Figure 11. A summary of suggestions for reviewing the contractor’s presentation of encountered performance is provided in Table 10. A contractor installed excess steel support (50% excess) for which he was paid, however, the contractor claimed an additional 7 months of delay with other minor claims that amounted to about $5.6 million. An analysis of the contractor’s own shift reports revealed the various downtimes were distributable to the categories illustrated in Figure 13. Each letter in Figure 13 represents various categories of downtime. Figure 13 makes it obvious, that the support downtime amounted to only 0.5 months due to all support installation.




Because of the analysis in Figure 13, the contractor could no longer claim the 7-month delay and settled for $1.2 Million, saving the government $4.4 million.

Differences between Anticipated and Encountered Performance Differences between anticipated and encountered construction performance is generally easily quantifiable and thereby easily represented not only numerically but also graphically. Occasionally, construction performance is not clearly linear or along a simple alignment and may require more substantial work before it can be presented in a concise and organized fashion. However, there has never been a project that could not be described, defined, or represented in terms of differences in construction performance. Suggestions for presenting differences in performance are outlined in Table 11. An example of a unique presentation of differences between anticipated and encountered performance is illustrated in Figure 14. It illustrates not only the magnitude of the difference in drilling rates but also clearly delineates and confirms the differences over a wide area, containing 800 drilled pile sockets. In all likelihood, the extent of the difference would have been rejected had it been based on only about 20 borings to represent differences in over 800 individual socket locations. It was possible in this case to use the rock uniaxial strength and the drilling rate to develop a statistical correlation curve. The correlation curve and the drilling rates were used to project probable uniaxial strengths. The actual and projected uniaxial strengths were used to plot the "strength" surface over the site. It is readily apparent that the difference between anticipated and encountered uniaxial strength is large and dimensionally extensive. "Material" differences have been defined in some contracts as a variation of 5-15% in the bill of quantities. However, smaller differences in construction performance and progress may prove substantial in overall cost simply because of their disproportionate effect on the time schedule. For example, in northern latitudes, small delays may extend work to an additional construction season. A summary of suggestions for reviewing the contractor’s presentation of differences in performance is provided in Table 12. An example where no differences in performance were found is illustrated in Figure 15. The anticipated values, calculated according to textbook equations without taking into account the actual condition of the dredge were compared to the actual field performance of the dredge under conditions similar to the bid estimates. It was found that the actual dredge capacity in the field was far below its estimated performance, even under ideal conditions in Figure 15.




Stable Geology, Construction Disturbance, & "Ground Response" The issues of “cause and effect" in construction within natural materials are often simplified to the extent that the geology is identified as the causative agent. This "blame" is not only unjustified, it is contrary to the most simple scientific principles. Geology pre-exists construction and even the existence of mankind. Pre-existing geology at rest is inherently stable, at least until disturbed by changes in boundary conditions and forces that affect the natural mass. It is only when construction disturbs conditions at rest that it is possible to see a change in the existing stability. It is the manner of disturbance of existing stable conditions that have the single most acute impact on the consequences. For example, in Figure 16, a tunnel is excavated in a blocky rock mass beneath the water table, the consequence or the "ground response" is that some of the blocks fall out and water infiltrates the tunnel opening. If an alternative "ground response" is desired, an alternative method of construction is necessary such as the use of a shield for temporary support. A more long term "ground response" may be attained by simply rock bolting the blocks. However, it is improbable that the rock bolting will prevent the water infiltration. In some cases, water infiltration may be of no consequence and therefore require no treatment or prevention. A contractor is likely to blame any perceived adverse condition as the cause for costlier construction. Consequently, a lack of a specific presentation of a quantitative, empirical, or graphic cause and effect relationship may invite suspicion on the part of the owner/engineer. However, not all cases can be illustrated with such simple cause and effect relationships, therefore these principles cannot be used as the sole determinant in all cases. The principles associated with developing credible cause and effect relationships may at times be very complex. For example, the distinction that "geological conditions" are used to define characteristics of geological materials, whereas "tunneling conditions" are used to define the effects that the geological conditions have on tunneling operations, have often been made. There is a fundamental and gross fallacy in this definition of "tunneling conditions". Since "geological conditions" pre-exist even the selection of a site for construction, one has no choice but to accept site conditions as the independent and pre-existing variable. One can only explore it, interpret the information, and apply it to minimize adverse consequences of man's construction activity. With that established, it becomes clear that any disturbance of, within, with, and around pre-existing natural materials can have a variety of consequences. However, it must be stressed, that behavior of natural materials can only be observed when subjected to some external force, disturbance, adjustment of existing forces, or conditions. Consequently, the behavior is merely a




"response" to external stimuli. Pre-existing conditions are inanimate and cannot produce consequences unless they are disturbed. Behavior of the natural materials, given pre-existing conditions, disturbances by changes in the sate of stress, using various methods, equipment, and resources can only be defined as a "response", or more specifically a "ground response". Use of the term "ground response" draws attention to the necessity for preceding external stimulus, such as the removal of material to create a hole in the ground. How the hole is created and the subsequent measures to minimize, eliminate, or mitigate the effects of the disturbance will have a consequence on "ground response". Disturbing a set of pre-existing inanimate conditions, with any particular construction activity, will have relatively predictable consequences. It is the chosen means of disturbance that has the greatest impact on the outcome and consequences that are often unjustly blamed on the geological conditions. The term "ground response" or "ground behavior under applied tunneling methods" best conveys that the controlling factors are not the pre-existing conditions (at rest), but the outside stimuli disturbing them. The distinctions of "geological conditions” and "tunneling conditions" hide the underlying principles associated with pre-existing conditions, external stimulus, and consequential "ground response" and should be viewed with skepticism in a differing site condition claim.

Cause and Effect Relationships Presentation of cause and effect relationships between differences in conditions and differences in performance is generally, and not always straightforward. Cause and effect relationships are best illustrated with X-Y plots of the independent variable (differences in conditions) and the dependent variable (differences in performance) in combination with statistical correlation. The differences in conditions must be related to the cause of the differences in construction performance. This does not preclude that other factors also may have contributed to the "effect”. Candor in the contractor's presentation can only strengthen his case and the owner's confidence in the legitimacy of the claim. For example, consequences of the contractor's various self-inflicted problems associated with equipment, coordination, and execution of the work, should be visibly extracted from the claim. Suggestions for presenting cause and effect relationships are outlined in Table 13. The cause and effect relationship illustrated in Figure 17 was developed from samples of rock from the tunnel and their established quartz content. These were plotted against TBM penetration rates calculated at the sampling location in the tunnel. The relationship is fairly well developed, even though there were other factors that




influenced the penetration rate, such as rock fabric, mineralogy, and rock hardness. Nevertheless, the relationship is quite good and clearly illustrates the effect of quartz content on TBM penetration, at least in this case. Figure 18 represents an empirical relationship between pile socket drilling rate and the uniaxial strength of the rock being drilled. The scatter is more than one might like, however, the relationship is reasonably well developed considering that rock mass characteristics (jointing, RQD) have not been taken into account in the relationship. Since the socketing operation is shallow, there is a great deal of variation in rock mass properties, such as presence of discontinuities, weathering, and how they affect drilling. Since socket-drilling operation occurs under water, the only possible observation of rock jointing and RQD was in cored samples. The cost of coring each socket was prohibited. In another case (Figure 19), the contractor claimed that water inflow affected tunnel excavation. In a presentation, the contractor provided a plot of weekly progress as a function of water inflow (4 weeks). There was no apparent relationship. In an attempt to determine the legitimacy of the relationship, a number of plots were prepared on a weekly basis, a monthly basis, and on a daily basis (Figure 20). None of these demonstrated a cause and effect relationship to tunnel excavation advance. Figure 19 & Figure 20 amply illustrate that although causes and effects could be meas-ured and displayed quantitatively, the relationship between inflow and progress was just not demonstrable and in all probability did not exist. A summary of suggestions for reviewing the contractor’s presentation of cause and effect relationships is provided in Table 14. Impact Presentation of DSC claim and related differences in construction performance must have a demonstrable impact in terms of construction duration, use of resources, and cost. The demonstration of impact and cause and effect are closely related and often one illustration may serve both purposes. Although the cause and effect relationships are intended to authenticate the association between cause and consequences, it also may be used to illustrate the range of impact both in time and distance (space). Similarly, although illustrations of impact are intended to depict magnitude of the consequences, they also will serve to identify causative agents. Suggestions for presenting impact are outlined in Table 15. A summary of suggestions for reviewing the contractor’s presentation of impact is provided in Table 16. The contractor is generally entitled to be compensated for impact that is measured between anticipated performance and encountered performance if the difference was




caused exclusively by the differing site conditions. On occasion, the contractor may (outside the limits of unanticipated conditions) exceed his anticipated performance, simply because of improved or better productivity. However, a greater extent of adverse conditions may slow his overall production far below the anticipated average. Since the contractor is entitled to his improved performance, the compensable difference in performance may be measured between the improved performance (rather than anticipated performance) and the actual encountered average performance due to more extensive "low performance ground conditions”. Similarly, the contractor is entitled to be compensated for the cost of mitigating impact of the unanticipated condition. The impact of unanticipated conditions may affect the project in various ways and justify compensation for impact on the following:

1. Main office overhead, 2. Intermediate office overhead, 3. Labor costs, 4. Loss of productivity, 5. Insurance and bonding, 6. Materials, 7. Equipment, 8. Interest expenses, and 9. Profit on the amount claimed.

Figure 21 illustrates an example of overbreak slowing TBM excavation. The straight line represents anticipated time-progress while the other curve represents the actual time-progress. In the actual time-progress curve, each of the horizontals or near horizontal portions of the curve was clearly related to overbreak. Overbreak in a machine-bored tunnel is considered very unusual and rare. Even more unusual was the fact that overbreak occurred in the invert. Overbreak had a clear impact on the operation and reduced the overall excavation rate far below what was anticipated, even thought the contractor was able to reach anticipated excavation rates when overbreak did not occur. The time-progress curve in Figure 21 illustrates various delays (breaks in the curve) that were associated with overbreak. In this case, the DSC was almost immediately recognized by the engineer. The cause and effect relationship could not be illustrated in the conventional manner by using an X-Y plot because the effect lagged the cause in terms of both time and location. The final illustration used parallel histograms, one showing the amount of overbreak, the other the labor efficiency (man-hours/foot of tunnel). This method of presentation was effective in depicting the relationship between the cause (overbreak) & effect (excavation inefficiency). Another method of displaying the impact of overbreak is to show average excavation efficiency (man-hours/foot of tunnel) for sections of tunnel that either were or sections that were not, influenced by overbreak as in Figure 21. Labor efficiency for excavation




directly affects cost. When the tunnel was completed, it was apparent that 3 zones could be distinguished in the tunnel on the basis of "ground response”. One of these sections was "as anticipated", the other two were the subject of claims. Figure 22 confirms that the unanticipated "ground response", consisting of unusual overbreak had an impact on the excavation labor by nearly tripling the man-hours required to excavate a foot of tunnel.

A contractor claimed decreasing production, increased costs, and consequential impact when encountering a gravel bank during his dredging operation. An analysis of the contractor's daily records, pay estimates, and time sheets showed that the excavation costs ($/CY) decreased when the gravel was encountered (Figure 23). Fulfilling Contract Requirements Contract requirements cannot be fulfilled solely at the time a differing site condition is suspected. Some of the requirements must have been fulfilled during the pre-bid investigation of the project, preparation of the estimate, and prior to the submission of the bid. If any doubts or challenges have been expressed by the owner/engineer, it is most expeditious to present a full narrative and supporting data for conformance to contract specifications or requirements. It is simpler to define specific contract requirements regarding differing site condition claims in the contract prior to bid. These include minimum site investigation, responsible preparation of a construction estimate, notice of the encounter of differing site conditions, investigation of differing site conditions, mitigation of impact, and presentation. Most contracts have specific provisions associated with:

1. Site visits / site investigation / examination / utilization of available data (documents, soil and rock samples, etc.)

2. Documentation of: 3. All assumptions (geotechnical, construction behavior and performance),

a. Interpretation (geotechnical, construction behavior and performance) b. Methods of prediction (geotechnical, construction behavior and

performance) c. Equipment selection (particularly when it has been challenged)

4. Notification of having encountered differing site conditions, 5. Mitigation of the impact of differing site conditions (general duty, contract

principle, common law principle), 6. Presentation / justification of entitlement, and 7. Presentation / justification of quantum.

Suggestions for presenting fulfillment of contract requirements are outlined in Table 17.




A review of the fulfillment of contractual obligations and requirements in a DSC is more specific, since the reviewer is particularly and perhaps even exclusively familiar with project provisions. Normally, the review must assure that:

• Reliance on contract documents, • Notice of possible differing site conditions, • Mitigation of impact, and • No other causes being responsible.

A summary of suggestions for reviewing the contractor’s presentation of the fulfillment of contract requirements is provided in Table 18. Other Considerations / Other Causes A recurring response from many owners/engineers to a differing site condition claim is the assertion that the contractor's unanticipated delays and cost overruns were self-inflicted. Not impossible or uncommon. However, the burden of proof rests on the owner. Any such allegations are best substantiated by quantitative and illustrative evidence. These claims may not be unreasonable; however, they provide no alternative to an adversary relationship. It is the responsibility of the owner/engineer to analyze the resident engineer's records to confirm them independently or disprove such allegations before they are made public. The contractor's counter arguments must meet similar rigorous standards. An example of causes other than a differing site conditions is illustrated in Figure 24. The anticipated hydraulic dredge pump capacity used in the construction estimate was 70%, however, based on field records (material moved, fuel consumption, and other data), the actual pump efficiency average out to be far less. The topic of "other considerations" is generally a sensitive and/or a controversial issue. It has been our experience that, on occasion, when a contractor makes a claim, the engineer may respond that the:

1. Conditions are really not that different, 2. Conditions "should" have been anticipated, 3. Contractor "should" have ________________° (easy to fill in the blank with

hindsight), 4. Project was mismanaged, 5. Equipment was inadequate or in poor condition, and 6. Contractor’s operations were inefficient.

It is not generally required for the contractor to defend himself against such expressed attacks. However, in court, even simple verbal claims are best neutralized by a preponderance of factual, quantitative, and graphic evidence. In other words, the effect of verbal claims can only be reversed by counter evidence of a higher order, potency, or obviousness.




Suggestions for presenting that no other conditions were responsible for inferior performance are outlined in Table 19. A summary of suggestions for reviewing that no other conditions were responsible for inferior performance are provided in Table 20.




4. THE PROCESS OF RESOLUTION The process of resolving a dispute or proving entitlement starts from a very basic position. First, it will be necessary to discover the cause of additional cost, slower productivity, or other impact which has given an indication of something not as anticipated. Analysis The analysis should begin as follows:

• Start from complaint • Find the cause • Develop the relationship • Determine the impact

Presentation The presentation of the results will require that they:

• Show differences in: • Conditions • Performance

• Illustrate cause and effect relationship • Illustrate impact • Document that all contract conditions have been fulfilled, and • No other cause has contributed to the impact (if at all possible).

Dealing with Parties The roles of each of the parties may not at fist be second nature to those involved; therefore, it is useful to describe them.

Contractor It is the contractor's responsibility to present the claim, independently of any self-evident manifestation of the claim. It is not uncommon, that in instances where the differing site condition may be generally obvious, the contractor often fails to make a good case for entitlement of fails to prove the full extent of the quantum. Often, the contractor fails to make any case at all with respect to entitlement while preparing a large and elaborate quantum package.




The contractor must prove his claim independent of whether it is self-evident or not.

Attorneys Do you wish to settle, fight, or just win? Although many attorneys have a wide range of competence, experience invariably confirms that they are better in certain functions than in others. If you generally want to fight, get a fighter. If you wish to negotiate, get a powerful negotiator. If you want a winner, ask about their record of accomplishment. In one case, where the available documentation was next to non-existent, an effective negotiator managed to show the owner that the contractor was entitled. This process took 2 years. Had this case gone to court, the contractor, for lack of basis (records), would have lost the case. Our experience in working with attorneys regarding technical issues has generally been favorable. However, it is essential that the attorney either have geotechnical and construction experience or be willing to systematically learn the subject from a broader view than the narrow essentials of the case. This learning should be devoid of inherent bias associated with the particular claim at hand. An attorney's tendency is to present the case in terms of argument and rhetoric, sometimes at the expense of “self-evident" exhibits that allows the adjudicating party to come to the conclusions independently. This may be particularly detrimental in the case when presenting cases to a Disputes Review Board knowledgeable about geotechnical and construction conditions, practical construction limitations, and differing site conditions. DRBs generally look unfavorably on presentations by attorneys.

Experts There are many definitions of an expert and in practical terms, the rules of court govern. These rules rely on education, experience, licensing, publication, “competence”, good character, centeredness, and public identity to establish expertise. In effect, there is a reliance on having various factors, as stated above, establish a high level of competence, hence an expert. Competence can much more simply and effectively be defined and established as “consistent effective action” and need not rely on the accoutrements. Experts may be qualified in a specialty or a much broader area; however, most judges rarely keep an expert from testifying. More likely, the expert’s testimony will determine the degree of credibility allotted by the adjudicator. In most cases, the credibility of the expert will depend on the level of preparation, succinctness of his testimony, keeping to the subject, and general credibility of the presentation. An expert is someone who:




1. Can present the documented raw facts in a manner that makes the facts self evident to all parties,

2. Allows interpretation and assessment within a narrow range, and 3. Does not rely on the individual's self defined "expertise".

Judges Experienced judges give great deal of weight to:

1. Level of preparation, 2. Credibility of witnesses, 3. Succinct testimony, 4. Testimony that sticks to the issues, 5. Pertinence of evidence, 6. Pertinence of laws, and 7. Appropriate legal framework.

A judge, who trains new appointees, expects cases to be prepared the same way that he used in the training, namely:

1. Establish the issues of the case, 2. Determine what is necessary to prove the case, 3. Lay out the necessities of proof with the use of:

a. Documents, b. Fact witnesses, c. Expert witnesses, d. Appropriate framework, and e. Applicable laws.

Arbitrators / Arbitration Our experience indicates that arbitration depends a great deal on the individual arbitrators. In most cases, experience with arbitration has been positive, with some negative experiences. The greatest danger is when arbitrators approach the issues emotionally or non-technically, and ascribe them to “feelings”. This may happen when panelists do not understand exploration, geological, geotechnical, ground behavior issues, the unique nature of underground construction, are unfamiliar with the details of a particular construction process, or are unaccustomed to dealing with philosophical foundation of law and practical aspects of a differing site condition claim. Consequently, it behooves the parties to avail themselves of individuals that are clearly analytical and conversant in ground condition issues, have specific construction experience, understand the intent of legal and technical issues, are able to be good “universal” observers, and develop critical analytical thinking.




Disputes Review Boards Although Dispute Review Boards (DRB) have been used on underground construction projects for the first time nearly 150 years ago, they have enjoyed an upsurge in the last 20 years. Through the efforts of the Committee on Contracting Practices of the Underground Technology Research Council, the sponsorship of the ASCE Construction Division, and the sponsorship of the American Institute of Mining Engineers, a definitive set of successful practices and guidelines have been published (ASCE, 1989). These guidelines provide recommendations for all aspects of establishing and using the DRB process, including contract clauses, method of selection, three party agreements, and holding the hearings. The Disputes Review Board Foundation has been established over two years now. As in arbitration, the success of a panel or board will depend a great deal on:

• The qualifications of the individuals, namely:

• A fundamental understanding of the philosophy of the applicable laws and contract language,

• A fundamental understanding of the technical elements of a differing site condition claim,

• The ability to think through the various components in appropriate combination, and

• The ability to prepare an integrated and harmonized finding or recommendation that is accepted by both parties;

• An adherence and maintenance, by the board, of reasonable:

• Rules of evidence and • Working protocol.

The DRB process has been and can be the most effective process for resolving disputes between the contractor and owner. Such boards have a free hand to probe the relevant issues aggressively; however, the process has occasionally been criticized because of allowed departure from general procedures and practices, rules of evidence, and protocols. The DRB Foundation has taken steps to insure the qualifications, competence, and consistency of its members. This is especially crucial now that smaller projects are beginning to use single member panels. The Foundation education committee has in the past provided training in:

1. The purpose, formation, contracting, and administration of dispute review boards and




2. Technical elements for entitlement of differing site condition claims.

Juries

Juries are rather unpredictable and may be inclined to decide based on emotional issues, particularly when the technical elements of a case are difficult to comprehend. Local juries tend to look unfavorably toward out of town defendants, consultants, and complex analyses, etc. Experiences with juries have been favorable unless they have been subjected to outside influences such as:

1. Time (having to decide a case on a Friday night against an out of town defendant),

2. Prejudices (against big companies; out of town companies; or “we just didn’t like the plaintiff”),

3. ?




5. RECOGNIZING DIFFERING SITE CONDITIONS This part of the course consists of some written material (that you can read at your leisure after the course) and the presentation of a number of case histories. The particular case histories were chosen to represent some classical issues, unusual situations, unique analyses, extraordinary presentations, and a variety of techniques. How and when does one realize that a differing site condition has been encountered?

1. What is different?

a. Is there more or less of something? i. Conditions? ii. Performance? iii. Cost? iv. Time?

b. Is there a difference in:

i. Time?

2. Are they related? (may not necessarily be obvious)

3. Is there an impact and what is it? Whatever course is taken to investigate any possible differences the responsibility for providing notice, investigation of differences, and mitigation of impact must be the appropriate parties. Difference in Performance Typical examples of notable differences in performance have been associated with drilling, tunnel excavation, micro-tunneling, trenching, and dredging as follows:

1. Material strength,

a. Slower drilling, boring, micro-tunneling, trenching, dredging rates, i. Linear, ii. Volumetric,

2. Lower advance rates,




3. Higher tool costs,

4. Greater overbreak / over excavation,

5. Under-break / under excavation,

6. Compressibility,

a. Greater powder factors, b. Greater support quantities,

7. Permeability,

a. Higher dewatering requirements, b. Greater water inflow, c. Higher grout takes,

8. Other,

a. Higher equipment wear, b. Longer equipment duration, c. Excess labor and other resources, etc.

A common shortcoming of the contractor's presentation is an inadequate establishment of reasonable anticipated performance and effective presentation of encountered and verifiable performance. It is necessary to establish a starting point (anticipated conditions) and document an ending point (encountered conditions) to make it possible to effectively illustrate the difference. Difference in Conditions Typical differences between anticipated and encountered conditions most commonly fall into the following categories:

1. In Soil variations in: quantities of:

a. Quantities of: i. Boulders ii. Gravel




iii. Sand iv. Silt v. Clay vi. Etc. vii. Vegetation growth

b. Permeability c. Behavior

2. In Rock (Intact Properties)

a. Top of rock b. Quantities c. Strength d. Slacking e. Swelling f. Hardness g. Boreability h. Deformability i. Permeability

3. In Rock (Mass Properties)

a. Properties and behavior of discontinuities, joints, shears, faults, b. Spacing c. Thickness d. Character e. Deformability f. Permeability / water inflow g. Gas infiltration h. Stresses i. Other behavior

Typical shortcomings of contractor's presentations have included failures to illustrate:

1. the difference between anticipated and encountered conditions based on: a. reasonable quantitative anticipated conditions, b. reasonably developed anticipated ground behavior, c. verifiable encountered conditions,

2. the difference between reasonably develop anticipated conditions and verifiable encountered performance, and




3. A cause and effect relationship between the difference in conditions & behavior and the differences in performance.

A number of case history examples of DSC claims are provided in the appendices.




6. EXERCISES Introduction In this section, examples of actual differing site condition claims that have been encountered, presented, evaluated, and resolved are presented. These exercises are best done in two groups to prepare documentation for entitlement for a differing site condition claim. The two groups will evaluate each other's prepared DSC claim and make recommendations for entitlement. There are two case histories, one for each team. After the preparation of each of the exercises, they should be given to the other team for evaluation and a vote as to whether the technical elements of a differing site condition claim have been fulfilled. Exercise 1 - Development of Anticipated Conditions and Performance

Description of Project “A-1” The project was designed as a pipe installation by trenching. Some of the borings did not go to the bottom of the trench excavation. The contractor parceled out most of the work to a pipe-jacking sub-contractor and all of the excavation for pipe-jacking occurred only at the bottom of the where the trench would have been. The pipe-jacking contractor encountered a great number of boulders. A number of documents and materials are available and provided as follows:

1. Exhibit A-1: Profile of Courthouse Drain, 2. Exhibit A-2: Boring Logs B-1 & 2 for Courthouse Drain, 3. Exhibit A-3: Tabulation of Anticipated Site Conditions (Courthouse Drain)

developed by Team Members Exhibit A-3, and 4. Exhibit A-4: Applicable Empirical Pipe-Jacking Experience.

Assignment for Project “A-1”




Your assignment is to provide:

1. Reasonable average anticipated boulders as a % of total excavation volume based on the boring logs (Exhibit A-2) & profile (Exhibit A-1) and tabulated in Exhibit A-3 under the following conditions:

a. Trench excavation to install the pipe shown in Exhibit A-1 and b. For the pipe-jacking alternative to install the pipe shown in Exhibit A-1.

2. Reasonable average anticipated progress rates using the average anticipated

percentage of boulders Exhibit A-3 and the empirical relationship provided in Exhibit A-4 to be tabulated in Exhibit A-3




Data for Project “A-1”

Exhibit A-1: Profile of Courthouse Drain




Exhibit A-2: Boring Logs B-1 & 2 for Courthouse Drain




Exhibit A-3: Tabulation of Anticipated Site Conditions (Courthouse Drain)

Exhibit A-4: Applicable Empirical Pipe-Jacking Experience

0123456

0 10 20 30 40Boulders, %

Exca

vatio

n R

ate,

m/d

ay

Experience Correlation Curve

Anticipated Team Member Boulder Volume,

cubic meter % Of Total Excavation Average Advance,

m/day




Solutions for Project A-1: The solutions consist of:

1. Anticipated boulder content,

a. For trench excavation is reasonable anywhere between 5-25%; the maximum possible is in the vicinity of boring 2 which cored through a 5 ft boulder for a total boring depth of 21 ft;

b. For pipe jacking excavation is reasonable between 0-5%; any amount above 5% is pessimistic and beyond the "reasonable optimism" to which a contractor is entitled;

2. Anticipated excavation rates for pipe jacking consistent with "reasonably

optimistic" boulder content and Exhibit A-4.




Exercise 2 - Presentation, Analysis, and Approval of a DSC Claim

Description of Project A-2: The project encountered unanticipated and extensive boulders. Project logs were kept; the original field construction record tabulation is shown in ?? and computer tabulation and calculations are provided in Exhibit A-5 including:

1. Excavation volume, 2. Volume / percentage of boulders encountered, 4. Applicable boring number, 5. Calculation of encountered boulder volume, and 6. Calculation of encountered excavation rate.

Assignment for Project “A-2” Proceed and:

1. Illustrate the following:

a. Boulder volume in terms of: i. Anticipated, ii. Encountered, and iii. Differences as a bar chart in Exhibit A-6,

b. Progress rate in terms of: c. Anticipated, d. Encountered, and e. Differences as a bar chart in Exhibit A-7,

2. Illustrate a cause and effect relationship using an X-Y graph on Exhibit A-8,

and

3. Illustrate impact on project duration using an X-Y plot with connected points on Exhibit A-9.

In real life, you may have to (not necessary to do that now) show that no other causes (appropriate equipment selection, project management, mitigation, etc.) caused the impact and that all contract conditions have been fulfilled.




Data for Project “A-2”

Exhibit A-5: Construction Record Tabulation/Calculations for Courthouse Drain

Days Anticipa-ted

Station, meters

Encoun-tered

Station, meters

Jacked Length, meters

Encoun-tered

Excavated Volume, cu

m

Encoun-tered Cumulative Excavated Volume,

cu m

Encoun-tered Boulder Volume,

cu m

Encountered Cumulative

Boulder Volume, cu m

Encoun-tered Bento-nite

Load

Encoun-tered Bento-nite Vol-

ume, cu m

Encoun-tered Cumu-lative Bentonite

Volume, cu m

Appli-cable Boring

Appli-cable Boring Station

Limits

13+281 387.10 387.10 BEGIN: 0.00 0.00 0.00 0.00 2.00 2 371.10 386.79 0.30 0.56 0.56 0.00 0.00 0.00 2.00 3 355.10 384.66 2.13 3.89 4.45 0.00 0.00 0.00 2.00 4 339.10 383.44 1.22 2.22 6.67 0.00 0.00 0.00 2.00 5 323.10 382.22 1.22 2.22 8.90 0.00 0.00 0.00 2.00 6 307.10 379.78 2.44 4.45 13.34 0.00 0.00 0.00 2.00 7 375.51 4.27 7.78 21.13 1.00 1.00 2.00 1.15 1.15 2.00 8 372.16 3.35 6.12 27.24 0.50 1.50 2.00 1.15 2.29 2.00 9 366.98 5.18 9.45 36.70 1.50 2.00 1.15 3.44 2.00

10 365.76 1.22 2.22 38.92 1.50 1.00 0.57 4.01 2.00 11 361.80 3.96 7.23 46.15 1.50 1.00 0.57 4.59 2.00 12 360.27 1.52 2.78 48.93 1.50 2.00 1.15 5.73 2.00 13 357.53 2.74 5.00 53.93 1.50 1.00 0.57 6.31 2.00 14 354.18 3.35 6.12 60.05 1.50 2.00 1.15 7.45 2.00 15 351.43 2.74 5.00 65.05 1.50 2.00 1.15 8.60 2.00 16 348.39 3.05 5.56 70.61 1.50 2.00 1.15 9.75 2.00 17 345.34 3.05 5.56 76.17 1.50 2.00 1.15 10.90 2.00 18 342.60 2.74 5.00 81.18 1.50 2.00 1.15 12.04 2.00 19 341.38 1.22 2.22 83.40 1.50 0.00 12.04 2.00 20 341.38 0.00 1.50 0.00 11+2021 338.63 2.74 5.00 88.40 1.50 2.00 1.15 13.19 1.00 22 336.50 2.13 3.89 92.30 1.50 2.00 1.15 14.34 1.00 23 332.54 3.96 7.23 99.52 1.50 2.00 1.15 15.48 1.00 24 330.40 2.13 3.89 103.42 1.50 2.00 1.15 16.63 1.00 25 328.57 1.83 3.34 106.75 1.50 1.00 0.57 17.20 1.00 26 326.14 2.44 4.45 111.20 1.50 2.00 1.15 18.35 1.00 27 325.22 0.91 1.67 112.87 1.50 0.00 18.35 1.00 28 324.61 0.61 1.11 113.98 1.50 0.00 18.35 1.00 29 324.00 0.61 1.11 115.09 1.50 0.00 18.35 1.00 30 323.39 0.61 1.11 116.20 1.50 0.00 18.35 1.00 31 323.09 0.30 0.56 116.76 3.00 4.50 2.00 1.15 19.50 1.00 32 321.56 1.52 2.78 119.54 3.00 7.50 0.00 19.50 1.00 33 320.34 1.22 2.22 121.76 7.50 0.00 19.50 1.00 34 318.52 1.83 3.34 125.10 2.00 9.50 0.00 19.50 1.00 35 317.30 1.22 2.22 127.32 3.00 12.50 3.00 1.72 21.22 1.00 36 315.47 1.83 3.34 130.66 4.00 16.50 1.00 0.57 21.79 1.00 37 313.64 1.83 3.34 134.00 2.00 18.50 0.00 21.79 1.00 38 311.51 2.13 3.89 137.89 2.00 20.50 1.00 0.57 22.36 1.00 39 309.37 2.13 3.89 141.78 1.50 22.00 2.00 1.15 23.51 1.00 40 306.93 2.44 4.45 146.23 2.00 24.00 2.00 1.15 24.66 1.00 41 306.32 0.61 1.11 147.34 24.00 42.00 24.08 48.74 1.00

Sum 81 147 85 49 Max 5.18 9.45 42.00 24.08 Avg 0.62 3.68 3.40 1.19 Min 0.00 1.00




Exhibit A-6: Exercise in the Difference in Conditions (Courthouse Drain)

0

5

10

15

20

25

Anticiapted EncounteredAnticipated / Encountered

Boul

der C

onte

nt, m

3AnticipatedEncountered

Exhibit A-7: Exercise in the Difference in Performance (Courthouse Drain)

0

1

2

3

4

5

Anticipated / Encountered

Prog

ress

Rat

e, m

/day

Anticipated Encountered




Exhibit A-8: Exercise in the Cause and Effect Relationship (Courthouse Drain)

0

2

4

6

0 1.5 3 4.5Boulder Volume, cu meters

Exca

vatri

on R

ate,

m

eter

s/da

y

Exhibit A-9: Exercise in Impact (Courthouse Drain)

300

320

340

360

380

400

0 10 20 30 40 50Excavation Days

Sta

tion,

met

ers Anticipated

Encountered




Solutions for Project “A-2” The solutions to Project A-2 are illustrated in Exhibit AA-1 through Exhibit AA-4.

Exhibit AA-1: Illustration of the Difference in Conditions (Courthouse Drain)

0

5

10

15

20

Anticipated / Encountered

Bou

lder

s %

of T

otal

Ex

cava

ted

Volu

me Anticipated

Encountered

Exhibit AA- 2: Illustration of the Difference in Performance (Courthouse Drain)

Prog

ress

Rat

e, m

/day

0

1

2

3

4

50% Boulders

10% Boulders

16% Boulders

Anticipated

Anticipated

Encountered




Exhibit AA- 3: Illustration of a Cause and Effect Relationship (Courthouse Drain)

Boulder Volume, cu meters

Exca

vatr

ion

Rat

e,m

eter

s/da

y

0.00

2.00

4.00

6.00

0.00 1.50 3.00 4.50

Exhibit AA-4: Illustration of Impact (Courthouse Drain)

Excavation Days

Sta

tion,

met

ers

300.00

320.00

340.00

360.00

380.00

400.00

0 10 20 30 40 50

Anticipated

Encountered

Outcome of Project “A-2”




The court awarded the contractor all that he claimed, however, the owner still refused to pay. Eventually the contractor settled for an amount less than the court award. One of the projects where unscrupulous owners avoid compensating what is justly the contractor's.




Exercise 3 – Presentation, Analysis, and Adjudication of a DSC Claim

Description of Project “B-1” The following information is provided for the exercise:

1. Exhibit B- 1: Bid Schedule , 2. Exhibit B- 2: Rock Removal Bid Item, 3. Exhibit B- 3: Specified Method of Rock Excavation Measurement , 4. Exhibit B- 4: Classifications & Definitions (a) for Rock Excavation, 5. Exhibit B- 5: Classifications & Definitions (b) for Rock Excavation , 6. Exhibit B- 6: Encountered Rock Quantities To Date,

Assignment for Project “B-1”

Do the following: 1. prepare an illustration of the difference between anticipated and encountered

rock quantities using a bar graph on Exhibit B- 7, 2. prepare a narrative of possible reasons why you might be entitled to additional

costs for excess rock removal considering it was a lump sum item using Exhibit B- 8,

3. list the types of effects unanticipated rock would have on construction excavation performance and why using Exhibit B- 9, and

4. list and enumerate the various impacts that unanticipated rock would have on construction duration and costs (list everything you can imagine!) using Exhibit B- 10.




Data for Project “B-1”

Exhibit B- 1: Bid Schedule

Item Approx. Quantity

Items Unit Price Extended Total, $

1. 9,500 Trafficmen $10.19 $96,805.002. 1,520 cu m Rock Removal $ /cu m 3. 7.6 cu m Concrete Cradles

and Encasements $ /cu m

Exhibit B- 2: Rock Removal Bid Item

From Minutes of Pre-Bid Conference The bid item for rock removal has been changed to a lump sum bid item as enumerated above. The linear footage of rock to be removed if a Contractor elects to go with underground construction methods for the entire project has been estimated to be 233 linear meters. Also attached herewith for informational purposes only are copies of boring logs B-302, D199, D201, D204, D205, D207, and D210.

Exhibit B- 3: Specified Method of Rock Excavation Measurement

Measurement of Rock Addendum: The measurement limits for determining the number of cubic meters of rock excavation shall be the pipe inside diameter plus one (1) meter.

Exhibit B- 4: Classifications & Definitions (a) for Rock Excavation




Classification (Structure Excavation) Rock - shall include rock in definite ledge formation, and severed or fragmented rock that cannot be removed by means of a 0.75 cubic meter shovel or backhoe, suitably powered, in good running conditions, and properly operated, without continuous drilling, blasting, barring and/or wedging, and boulders or portions thereof of one cubic meter or more in volume, and concrete and cement masonry structures (not specified to be removed under other items of work).

Exhibit B- 5: Classifications & Definitions (b) for Rock Excavation

Classification and Definitions (Trench Excavation) Rock - shall include rock in definite ledge formation, and severed or fragmented rock that cannot be removed by means of a shovel or backhoe, suitably powered, in good running conditions, and properly operated, without continuous drilling, blasting, barring and/or wedging, and boulders or portions thereof of 0.5 cubic meter or more in volume, and concrete and cement masonry structures (not specified to be removed under other items of work). A suitable "shovel" or "backhoe" is defined as equipment of the proper type, size and power to perform the excavation required.

Exhibit B- 6: Encountered Rock Quantities To Date

Encountered Rock: 733 lineal meters by trenching and tunneling (to date, project was incomplete)

Exhibit B- 7: Exercise in the Difference in Rock Quantities




0

200

400

600

800Li

neal

Fee

t of R

ock

Exca

vatio

n, m

eter

s AnticipatedEncountered

Exhibit B- 8: Exercise in Entitlement

Prepare a narrative of possible reasons why you might be entitled to additional costs for excess rock removal considering it was a lump sum item. _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ___________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________




Exhibit B- 9: Exercise in the Effect of Unanticipated Rock List the types of effects unanticipated rock would have on construction performance. _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________




Exhibit B- 10: Exercise in the Impact of Unanticipated Rock List and enumerate the various impacts that the unanticipated rock would have on construction duration and costs (list everything you can imagine!). ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________




Solutions for Project “B-1” To be developed




Exercise 4 – Presentation, Analysis, and Adjudication of a DSC Claim (to be developed)

Description of Project “B-2” On the same project, difficulty in dewatering, pipe jacking face stability, and excavation was encountered.

• You will receive:

• anticipated, • encountered, and • differences in silt content on the same job ().

Assignment for Project “B-2” • Do the following:

• Prepare a single graph to illustrate the difference of silt content along the

excavation alignment for each sample station using bar graphs on Exhibit B- 2.

Evaluation of Project “B-2” Each group will vote on whether the individual elements of a differing site condition have been fulfilled by the other group. Then each group will vote whether to approve the other group's DSC claim and the results of the vote will be recorded in Exhibit B2- 3.




Data for Project “B-2”

Exhibit B2- 1: Data for Anticipated and Encountered Silt

Relevant Boring

Influence of Boring

Anticipated Silt, % Low Avg. High

Sample Station

Sample Location

Date Eleva-tion, ft

Depth, feet Encountered Silt , %

Difference, +% Difference, -%

B-10 0 5 10 92+90 Well 65 3Mar83 6.00 18.80 39.70 34.70 B-10 0 5 10 93+20 Well 64 3Mar83 0.00 24.80 26.60 21.60 B-10 0 5 10 94+05 Well 51 3Mar83 10.00 14.80 2.00 -3.00

95+00 B-11 0 5 10 99+75 Well 32 3Mar83 -7.00 33.00 52.60 47.60

100+00 B-11 0 5 10 100+30 Well 30 3Mar83 5.00 19.80 12.40 7.40 B-11 0 5 10 101+47 Well 26W 20Jan83 10.00 15.00 7.40 2.40 B-11 0 5 10 101+47 Well 26W 20Jan83 1.00 24.00 23.10 18.10 B-11 0 5 10 102+68 103'W#13 3Mar83 3.50 21.30 18.50 13.50 B-11 0 5 10 102+68 103'W#13 3Mar83 2.00 22.80 12.20 7.20 B-11 0 5 10 103+71 Pit 13 3Mar83 2.00 22.80 8.90 3.90 B-11 0 5 10 103+71 Pit 13 3Mar83 1.00 23.80 7.90 2.90 B-12A 10 15 20 104+81 3Mar83 5.00 19.80 23.00 8.00 B-12A 10 15 20 104+81 3Mar83 3.00 21.80 28.60 13.60

105+00 B-12A 10 15 20 105+75 25Feb83 3.50 21.00 9.90 -5.10 B-12A 10 15 20 106+20 25Feb83 6.00 19.00 1.10 -13.90 B-12A 10 15 20 106+20 25Feb83 3.00 21.50 14.50 -0.50 B-12A 10 15 20 106+71 Pit 14 25Feb83 6.00 19.00 32.10 17.10 B-12A 10 15 20 106+71 Pit 14 25Feb83 1.00 24.00 11.00 -4.00 B-12A 10 15 20 107+14 25Feb83 8.00 17.00 13.70 -1.30 B-12A 10 15 20 107+14 25Feb83 4.00 21.00 8.40 -6.60

110+00 Pit B ----------------------------------------------------------------------------------------------------------------------------------------------- B-13 10 15 20 112+15 Near B-13 20Aug82 0.00 25.00 47.00 32.00 B-13 0 5 10 112+30 Pit 15A 20Aug82 15.50 10.50 44.10 39.10 B-13 0 5 10 112+30 Pit 15A 20Aug82 8.00 16.50 88.10 83.10 B-13 0 5 10 113+16 Pit 15 20Aug82 8.00 10.50 86.00 81.00 B-13 20 27 35 113+16 Pit 15 20Aug82 5.00 20.50 66.90 39.90 B-13 20 27 35 113+30 20Aug82 4.50 21.00 46.80 19.80 B-13 0 5 10 113+30 20Aug82 2.80 23.70 84.70 79.70

115+00 B-13 0 5 10 116+22 Pit 16 20Aug82 11.00 14.50 30.10 25.10 B-13 0 5 10 116+22 Pit 16 20Aug82 9.00 16.50 6.80 1.80 B-13 0 5 10 116+22 Pit 16 20Aug82 8.00 17.50 54.10 49.10 B-13 20 27 35 116+22 exc face 20Jan83 7.00 18.50 91.70 64.70 B-13 20 27 35 116+93 exc face 20Jan83 6.30 20.50 43.10 16.10 B-13 20 27 35 117+00 exc face 20Jan83 8.00 22.00 90.00 63.00 B-13 20 27 35 117+00 exc face 20Jan83 5.00 19.00 56.30 29.30 B-14 120+00 35 42 50 120+00 Pit 18 20Jan83 12.30 14.00 6.80 -35.20 B-14 35 42 50 120+00 Pit 18 20Jan83 10.00 16.30 73.90 31.90 B-14 35 42 50 122+75 25Feb83 8.00 20.30 0.60 -41.40 B-14 35 42 50 122+75 25Feb83 6.00 22.50 60.60 18.60 B-14 20 27 35 123+10 25Feb83 23.50 5.00 29.70 2.70 B-14 20 27 35 123+20 25Feb83 25.50 3.00 35.10 8.10 B-14 20 27 35 123+35 25Feb83 20.50 8.00 21.50 -5.50 B-14 124+34 35 42 50 124+34 Pit 20 20Aug82 15.50 13.50 14.40 -27.60




Exhibit B2- 2: Exercise in the Difference in Conditions (B-T Silt)

-100

-50

0

50

100

115+

00

120+

00

Sample Station

Diff

-ere

nce,

-%

Silt > anticipated Silt < anticipated

Exhibit B2- 3: Results of DSC Claim Vote ___________________________________________________________ ITEM TO APPROVE Case A Case B _________________________________________________________ Difference in Conditions Yes____ No____ Yes____ No____ Difference in Performance Yes____ No____ Yes____ No____ Cause and Effect Relationship Yes____ No____ Yes____ No____ Impact Yes____ No____ Yes____ No____ Contract Requirements Yes____ No____ Yes____ No____ No Other Cause Yes____ No____ Yes____ No____ Approval of the DSC Claim for Entitlement Yes____ No____ Yes____ No____




Solutions for Project “B-2”

Exhibit BB- 1: Illustration of the Difference in Conditions

0100200300400500600700800

Leng

th o

f Roc

k E

xcav

atio

n,

met

ers

AnticipatedEncountered

Exhibit BB- 2: Narrative for Entitlement ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________




Prepare a narrative of possible reasons why you might be entitled to additional costs for excess rock removal considering it was a lump sum item.

1. notwithstanding that rock was a lump sum item, the excessive quantities warrant a challenge to the lump sum item,

2. greatly exceeds the original quantities, and 3. ask an attorney.

Exhibit BB- 3: Illustration of Effect of Unanticipated Rock The effect of unanticipated rock on construction performance would:

1. require drilling & blasting 2. require removal of boulders & rock may require removal of conveyor belt, 3. cause instability of the overlying flowing silts while mining the rock and boulders

which would in turn unanticipated stabilization requirement for the soil.

Exhibit BB- 4: Illustration of the Impact of Unanticipated Rock List and enumerate the various impacts that the unanticipated rock would have on construction duration and costs (list everything you can imagine!).

• time delay due for: • drilling & blasting, • slower progress removing rock and boulders, • required stabilization of overlying soil,

• additional costs for:

• drilling equipment, • powder, • labor, • service equipment.




Exhibit BB- 5: Illustration of the Difference in Conditions

Sample Station

Diff

-ere

nce,

-%

-100

-50

0

50

100

95+0

0

100+

00

105+

00

110+

00

115+

00

120+

00

124+

34

Silt > anticipated Silt < anticipated




Outcome of Project “B-2” The case went to trial and to arbitration. The contractor first sued the owner and engineer. Then the contractor and owner sued the engineer. the contractor won, the engineer lost both times, and the owner lost once. Exercise 5 – ? Description of Project ? Assignment for Project “?” Solutions for Project “?” Case Outcome




7. REFERENCES ASCE (1997). Geotechnical Baseline Reports for Underground Construction, 40p. Mathews, A. A. (1985). Unpublished Manuscript. Tarkoy, P.J. (1998). Differing Site Conditions, Tunnels and Tunneling (March). Tarkoy, P.J., (1995). Contract Documents For Tunnelling and Underground Construction for Dealing with Geotechnical Issues to Avoid and Resolve Disputes, 13th Canadian Tunneling Conference, Montreal, 18-20 Oct. Tarkoy, P.J., (1995). PLIEGO DE CONDICIONES PARA CONSTRUCCIÓN DE TÚNELES Y CONSTRUCCIÓN SUBTERRANEA para tratar con Asuntos Geotécnicos para Evitar y Resolver Disputas, Congresso Mexicano Ingenieríera de Túneles y Obras Subterraneas, Mexico City, 8-11 Oct, in press. Tarkoy, P.J., (1995). Technical Elements for Entitlement of a Differing Site Condition Claim, Congresso Mexicano Ingenieríera de Túneles y Obras Subterraneas, Mexico City, 8-11 Oct, in press. Tarkoy, P.J. (1992). Is the Owner Receiving Full Value for Site Exploration?, Proceedings of the International Congress Towards New Worlds in Tunneling/Acapulco/16-20 May 1992, p. 103-110. Tarkoy, P.J. (1991). Appropriate Support Selection, Tunnels and Tunneling 23(10):42-45 (October). Tarkoy, P.J. and Marconi, M. (1991). Difficult rock comminution and associated geological conditions. In: Tunneling '91, Sixth International Symposium, 14-18 April 1991, Novotel, London, England. Institute of Mining and Metallurgy, Elsevier Applied Science, London. pp. 195-207. Tarkoy, P.J., (1989). Differing Site Conditions Often Generate Claims. The Military Engineer 81(531):72-75 (September/October). Tarkoy, P.J. (1988). The Stuff that Claims Are Made Of. World Tunneling 1(3):249-253 (September). Tarkoy, P.J. (1987). Differing Site Conditions and the Personal Computer. In: Jacobs, J.M. and Hendricks, R.S. (eds.), Proceedings, Volume 2, 1987 Rapid Evacuation and




Tunneling Conference, New Orleans, Louisiana, June 14-18. Society of Mining Engineers, Littleton, CO. pp 1271-1286. Tarkoy




8. TABLES




Table 1: Recommendations for the Presentation of Reasonable Anticipated Conditions DO: • Use all applicable data and reference sources (explain data excluded), • Have reasonable anticipated conditions be consistent with quantitative units and values provided in

the contract documents, • Use appropriate averaging, application, and area wide/depth of application and interpretation

consistent with geological, engineering, and construction standards, • Use reasonable interpretation of applicable classification schemes in cases where qualitative

definitions have been used and values must be quantified, • Present factual characteristics separate from interpreted construction behavior, • Provide narrative for data utilization and interpretation, • Base evaluations on reasonably available, existing, or published information, including site visit & site

investigation, available geotechnical data and interpretations, local experience & local excavations, and construction specifications;

• Illustrate average values, ranges, of applicable properties or characteristics, by project segment, material type, etc., with respect to depth and area wide extent, using frequency distribution diagrams, bar charts, hi-lo graphs, pie charts, whatever illustrative techniques are necessary (e.g. - 3-D surface).

• Have assessments be consistent with contractor's expertise, available time, and reasonable practice, ... remember

• It is unreasonable to expect the same level of professional interpretation from the contractor as the engineer, particularly in the time available during the bidding period;

• It is reasonable to require contractors to have minimum level of competence regarding natural materials, "general knowledge, and common sense";

• Exercise reasonable precedence of specific data over general & site specific data over off-site data. DO NOT: • Include any information unavailable at bid time or not included in contract or associated documents

unless specifically referenced or pertinent, • Confuse material properties with "ground response," • Use verbal descriptions when quantitative values are available, and • Make unsubstantiated claims for which you have no evidence.




Table 2: Recommendations for the Review of Reasonable Anticipated Conditions DO: • Check that appropriate and applicable steps have been completed by the contractor, • Check that applicable data was used, investigate omitted data, check data sources, • Check for consistency of properties, characteristics, units, etc., • Investigate inconsistencies, • Check all calculations for relevance, applicability, dimensional applicability (depth and area wide

extent), • Check the basis for the engineer's original quantities (if applicable), and • Substantiate with your evidence or references, any doubts or disagreements you have with the

contractor's presentation. DO NOT: • Overlook possible reasons why some data may have been omitted, • Take any of the methods of calculations (for averages and ranges), interpretations for granted, and • Make unsubstantiated challenges.

Table 3: Recommendations for the Presentation of Verifiable Encountered Conditions DO: • Use all applicable data and reference sources (explain data excluded), • Present encountered conditions consistent with pre-bid data and quantitative units and values

provided in the contract documents, (specific material properties, units of measure, method of testing, etc.),

• Use appropriate methods of averaging, application, and area wide or depth of application and interpretation consistent with geological, engineering, and construction standards,

• Make the presentation in terms of factual properties separate from interpreted construction behavior as necessary,

• Provide narrative of how data was measured, • Follow pre-agreed guidelines (measurement, testing, mapping or representation of geological

conditions or "ground response"), and • Illustrate average and ranges of applicable properties or characteristics, by project segment, material

type, etc., with respect to depth and area wide extent, using frequency distribution diagrams, bar charts, hi-lo graphs, pie charts, whatever illustrative techniques are necessary.

DO NOT: • Present obscure, unrelated, or inconsistent material properties, • Confuse material properties with "ground response," and • Make unsubstantiated claims for which you have no evidence.

Table 4: Recommendations for the Review of Verifiable Encountered Conditions DO:




• Check that appropriate and applicable steps have been completed by the contractor, • Reconcile contractor's records with those of the inspectors and resident engineer, • Check that encountered conditions are relevant to the DSC issues and could cause the

consequences that may be claimed, • Check that quantitative results have been determined according to reasonable, professional, or

standard practices, • Check for consistency of properties, characteristics, units, etc. and investigate inconsistencies, • Check that selected encountered properties were available in the pre-bid data, and • Substantiate with your evidence, any doubts or disagreements you have with the contractor's

presentation. DO NOT: • Take the accuracy or relevancy of measures of encountered conditions for granted, • Overlook inconsistencies in data comparisons (such as permeability vs. inflow), • Assume that test or measured results are absolute (some tests, more than average, are prone to

extraneous influences), and • Make unsubstantiated challenges.

Table 5: Recommendations for the Presentation of Differences in Conditions DO: • Use consistent geotechnical properties, characteristics, and units, • Use and reference sources of all pertinent data (explain data omitted), • Check that averages and other values have been calculated according to reasonable or standard

practices (taking into account the type of construction, depth of excavation, proportions of the volume of exploratory samples to the total excavation volume, type of material characterization and testing available, etc.),

• Use appropriate methods of averaging, application, and area wide or depth of application and interpretation consistent with geological, engineering, and construction standards,

• Illustrate average values, ranges, of applicable properties or characteristics, by project segment, material type, etc., with respect to depth and area wide extent,

• Using frequency distribution diagrams, bar charts, and hi-lo graphs, pie charts, whatever illustrative techniques are necessary (e.g. - 3-D surface).

DO NOT: • Mix properties and values, • Mix properties, characteristics, behavior, and "ground response", and • Make unsubstantiated claims for which you have no evidence.

Table 6: Recommendations for the Review of Differences in Conditions DO: • Check that appropriate and applicable Steps have been completed, • Investigate that all data has been used that should be used,




• Check that averages and other values have been calculated according to reasonable or standard practices (taking into account the type of construction, depth of excavation, proportions of the volume of exploratory samples to the total excavation volume, type of material characterization and testing available, etc.),

• Check that anticipated and encountered conditions have been properly projected and defined over the entire site, appropriate to depth and area wide extent (common sense & engineering geology practices), and

• Determine the magnitude of the differences, and • Substantiate with your evidence, any doubts or disagreements you have with the contractor's

presentation. DO NOT: • Overlook that differences may be a consequence of errors, omissions, or inaccuracies in

measurement, etc. and • Make unsubstantiated challenges.




Table 7: Recommendations for the Presentation of Reasonable Anticipated Performance DO: • Present the estimator's assessment of (reasonable) construction performance with a clear

demonstration of reliance on available information such as: • Anticipated geotechnical conditions (shear strength, grain size distribution, permeability, water table,

uniaxial strength, Total Hardness, and other index properties), • Practical experience (with similar circumstances & equipment, with adjustments for deviations), • In-house developed case history database, empirical relationships, and methods of utilization, and • Published relationships (hardness drillability & boreability; rock mass rating-support); • Check that the logic and development of anticipated performance can be followed by a high school

student, • Demonstrate that the determination of reasonable anticipated construction performance has been

based on a variety of sources, parameters, and experiences, • Point out reliance on anticipated conditions, • Take into account the equipment being used, • Reference sources of experience, empirical relationships, and past experience, • Use appropriate methods of averaging, application, and area wide application and interpretation

consistent with geological, engineering, and construction standards, • Illustrate average values, ranges, of performance, by project segment, material type, etc., with

respect to depth and area wide extent, using frequency distribution diagrams, bar charts, hi-lo graphs, pie charts, whatever illustrative techniques are necessary (e.g. - 3-D surface).

• Use performance variables that are affected by anticipated conditions, and • Check that assessments are consistent with contractor's expertise, available time, and reasonable

practice. DO NOT: • Expect the engineer to figure out how you arrived at your figures, • Leave it up to anyone else to figure out your logic, and • Make unsubstantiated claims for which you have no evidence.




Table 8: Recommendations for the Review of Reasonable Anticipated Performance DO: • Check that appropriate and applicable steps have been completed by the contractor, • Assure that the contractor's anticipated performance is reasonable, based on all available data, past

experience, standard determinations, etc., credible assessments and interpretation, and reproducible independent analyses;

• Investigate why any data was omitted, • Cross-reference source of data used if not already done so, • Check for consistency of properties, characteristics, units, etc. • Investigate inconsistencies, • Check calculations for relevance and applicability (complex and contorted calculations are suspect),

and • Substantiate with your own evidence, any doubts or disagreements you have with the contractor's

presentation. DO NOT: • Rely on what "appears" reasonable, • Overlook possible reasons why some data may have been omitted, • Take any of the methods of calculations (for averages and ranges), interpretations for granted, • Expect the contractor to provide the evidence for challenging his own claim with regard to the

reasonability of anticipated performance, and • Make unsubstantiated challenges.

Table 9: Recommendations for the Presentation of Verifiable Encountered Performance DO: • Present encountered performance consistent with the construction estimate (specific performance

parameters, standard units of measure and methods, etc.), • Use appropriate methods of averaging, application, and area wide application and interpretation

consistent with geological, engineering, and construction standards, • Follow pre-agreed guidelines or standards for measurement and provide narrative of how data was

measured, • Illustrate average values, ranges, of performance, by project segment, material type, etc., with


DO NOT: • Present obscure and unrelated performance variables, • Compare inconsistent performance parameters, • Use units that do not relate to or have are a consequence of the unanticipated conditions and • Make unsubstantiated claims for which you have no evidence.




Table 10: Recommendations for the Review of Verifiable Encountered Performance DO: • Check that appropriate and applicable steps have been completed by the contractor, • Cross-reference contractor's performance claims with inspector's records, the resident engineer's

records, and checking all underlying data, • Identify delays, low performance, and use of additional resources should be scrutinized to the assure

that they can be related and associated with the unanticipated conditions, • Substantiate with your own evidence, any doubts or disagreements you have with the contractor's

presentation. DO NOT: • Take for granted that encountered performance parameters are appropriate for the DSC issues at

hand, • Take for granted that reported performance parameters have a relationship with unanticipated

conditions, • Assume that claimed delays are based in fact, and • Make unsubstantiated challenges.

Table 11: Recommendations for the Presentation of Differences in Performance DO: • Use all pertinent data, • Use performance parameters & units consistent with the estimate, • Quantify performance parameters, • Perform all necessary calculations to permit illustration of differences in performance, especially when

the work is not linear or purely volumetric, • Use differences in averages and ranges calculated according to reasonable and standard

engineering and construction practices, • Illustrate average values, ranges, of performance, by project segment, material type, etc., with


• Get help if you have trouble demonstrating/illustrating differences in performance, DO NOT: • Give up, • Mix properties and values, and • Make unsubstantiated claims for which you have no evidence.




Table 12: Recommendations for the Review of Differences in Performance DO: • Check that appropriate and applicable steps have been completed by the contractor, • Reconcile reasonable anticipated performance and verifiable encountered performance, • Check that selected performance parameters can be associated with the unanticipated conditions,

other inefficiencies, other extraneous influences, or the contractor's self-inflicted problems, • Prepare your own graphic comparisons (if necessary), • Substantiate with your own evidence, any doubts or disagreements you have with the contractor's

presentation. DO NOT: • Take for granted that the presented differences are relevant to the issue, • Accept on face value that the differences can be substantiated by construction records, • Overlook the foundation and basis of what appear to be obvious and clear differences, and • Make unsubstantiated challenges.

Table 13: Recommendations for the Presentation of Cause and Effect Relationships DO: • Use X-Y plots with the independent variable (differences in conditions) and the dependent variable

(differences in performance) in combination with statistical correlation, • Use necessary techniques to investigate cause and effect relationships, • Use quantitative (intact and mass) material properties and behavior, • Use a quantitative measure of construction performance, • Select a pre-existing and fundamental (intrinsic) relationship between the two variables, • Realize a reasonable correlation (coefficient) between two or more variables, • Remove any extraneous causes or self-inflicted problems or inefficiencies which are not associated

with the difference in conditions, and • Exclude consequences not caused by unanticipated conditions. DO NOT: • Avoid this step (it is essential) and • Make unsubstantiated claims for which you have no evidence.




Table 14: Recommendations for the Review of Cause and Effect Relationships DO: • Check that appropriate and applicable steps have been completed by the contractor, • Check that quantifiable and verifiable material properties are utilized, • Check that quantitative and acceptable measure of performance are utilized, • Check that a fundamental (intrinsic) and relatively obvious relationship exists between the variables, • Not include causes or effects that are unrelated to the unanticipated conditions, • Check for reasonable correlation (coefficient), and • Check for a rationale that confirms the degree of correlation obtained is reasonable under the

circumstances. DO NOT: • Overlook that there may be extraneous causes in the empirical cause and effect relationships, • Overlook that consequences may be related to construction technique rather than existing conditions,

and • Make unsubstantiated challenges.

Table 15: Recommendations for the Presentation of IMPACT DO: • Illustrate that the impact was caused by (unanticipated) differing site conditions, • Illustrate the impact on a time scale (shifts, days, date, day, etc.), • Illustrate the impact on a dimensional scale (space) such as depth, alignment station, coordinates,

cumulative lengths, cumulative volumes of excavation, etc., • Demonstrate that the impact was unrelated or not caused by any other construction activity or agent, • Specifically address implications that problems were unrelated to unanticipated conditions (may

preempt doubts or suspicions), • Demonstrate and document efforts implemented to mitigate impact. DO NOT: • Leave the impact of unrelated factors included in your presentation (it will compromise your

credibility) and • Make unsubstantiated claims for which you have no evidence.




Table 16: Recommendations for the Review of Impact DO: • Check that appropriate and applicable steps have been completed by the contractor, • Ascertain that all impact claimed is specifically, directly, and exclusively related to the differing site

conditions, keeping in mind the contractor's responsibility to mitigate DSC's impact, • Construction inefficiencies, equipment problems, and other operational difficulties are not included

with the impact associated with the DSC, and • Make unsubstantiated claims for which you have no evidence. DO NOT: • Fail to investigate the possibility of extraneous causes and • Make unsubstantiated challenges.

Table 17: Recommendations for the Presentation of Fulfilling Contract Requirements DO: • Specifically list applicable contract requirements associated with a differing site condition claim and • Specifically address each of the applicable contract requirements associated with a differing site

condition claim. DO NOT: • Take contract requirements (written or unwritten) for granted and • Make unsubstantiated claims for which you have no evidence.




Table 18: Recommendations for the Review of Fulfilling Contract Requirements DO: • Check that appropriate and applicable steps have been completed, • Check for all pertinent and applicable contract requirements have been met pertaining to: Site Investigation,

Reliance, Demand of Notice, Documentation, Mitigation and any other requirement specifically in the contract.

• The contractor has mitigated (as much as possible) the impact of a confirmed differing site condition, and

• That all claimed impact is attributable to the DSC (if it is not, counter evidence must be provided in rebuttal).

DO NOT: • Make unsubstantiated challenges.

Table 19: Recommendations for the Presentation That No Other Conditions Were Responsible DO: • Preempt any doubts, aspersions, etc., by dealing with them directly. DO NOT: • Get into issues other than technical or factual, • Get into matters unrelated to the DSC issues, and • Make unsubstantiated claims for which you have no evidence.

Table 20: Recommendations for the Review to Determine That No Other Conditions Were Responsible

DO: • Check that appropriate and applicable steps have been completed by the contractor, • Check that no other conditions were responsible for increased costs and time delays. DO NOT: • Make unsubstantiated claims for which you have no evidence.




9. FIGURES




Figure 1: REASONABLE ANTICIPATED CONDITIONS (UCS Hi-Lo)

1 0 1

1 7

4 3

6 9

1 7

4 33 8

1 7

4 3

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

8 7 - 1 9 8 7 - 2 3 A v gS o u r c e B o r i n g

Uni

axia

l Stre

ngth

, Mpa

M a x i m u m

A v e r a g e

M i n im u m

Figure 2: UNREASONABLE ANTICIPATED CONDITIONS (Bar)

12

50

3

14

0

10

20

30

40

50

60

B o rin g s G rave l P its C o n tra c to rA n tic ip a ted

E n c o u n te red

S o u rce o f D ata

Gra

vel,

%

R ea s o n ab le A n tic ip a ted

U n rea s o n ab le A n tic ip a ted

E n c o u n te red

Figure 3: CREDIBLE ENCOUNTERED DATA (Hi-Lo)

0

100

200

300

Ant

icip

ated

Gra

nite

Enc

ount

ered

Gra

nite

Enc

ount

ered

Gra

nite

(2)

Enc

ount

ered

Met

a-A

ndes

ite

Enc

ount

ered

Por

phyr

y

Source / Rock Type

Uni

axia

l Str

engt

h, M

pa

Max Avg Min




Figure 4: NON-CREDIBLE ENCOUNTERED DATA (Frozen Weir)

0

2 0 0

4 0 0

6 0 0

8 0 0

1 , 0 0 0

1 , 2 0 0

1 , 4 0 0

1 , 6 0 0

1 , 8 0 0

2 , 0 0 0

1 3 1 6 1 9 1 1 2 1 1 5 1 1 8 1 2 1 1 2 4 1 2 7 1 3 0 1 3 3 1 3 6 1

C u m u l a t i v e E x c a v a t i o n T i m e , s h i f t s

Wei

r Flo

ws,

lite

rs/s

ec R a i n y S e a s o n

F r o z e n W e i r

Figure 5: DIFFERENCE IN CONDITIONS (by Tunnel Zone)

0

5 0

1 0 0

1 5 0

A B C D E F G H

T u n n e l R o c k Z o n e s

Tota

l Har

dnes

s

A n t ic ip a t e d E n c o u n t e r e d

Figure 6: DIFFERENCE IN CONDITIONS (UCS / Hi-Lo)

0

1 0 0

2 0 0

3 0 0

A n t i c i p a t e d E n c o u n t e r e d

Uni

axia

l Str

engt

h, M

pa M a x A v g M i n




Figure 7: NO DIFFERENCE IN CONDITIONS (Water Inflow)

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

1 31 61 91 121 151 181 211 241 271 301 331 361Cumulative Excavation Time, shifts

Wei

r Flo

ws,

lite

rs/s

ec Rainy Season

Frozen WeirAnticipated Inflow = 1,800 liters/minute

Inflow Included in Tunnel Price liters/minute

Figure 8: BASIS OF REASONABLE PERFORMANCE

0

5

10

15

0 50 100 150 200 250

Total Hardness

Pene

trat

ion

Rat

e, ft

/hr

Figure 9: BASIS OF UNREASONABLE PERFORMANCE

0

5

10

15

0

10,0

00

20,0

00

30,0

00

40,0

00

50,0

00

Cutter Load (Fn), lbs

Pene

trat

ion

Rat

e, ft

/hr




Figure 10: CATERPILLAR RIPPABILITY CHART

To be added in next version




Figure 11: UNREASONABLE ANTICIPATED PERFORMANCE

0 %

2 7 %

7 3 %

0 %

2 7 %7 3 %

0

5 0 0

1 , 0 0 0

1 , 5 0 0

0 % 1 0 % 2 0 % 3 0 % 4 0 % 5 0 % 6 0 % 7 0 % 8 0 %G r a v e l / S a n d C o n t e n t

Dre

dge

Pum

ping

Rat

e, c

ubic

met

ers/

hour

U n r e a s o n a b l e A n t i c i p a t e d C a p a c i t y A c t u a l C a p a c i t y

Figure 12: VERIFIABLE PERFORMANCE (Dredge Rate)

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

0 2 0 4 0 6 0 8 0 1 0 0P e r c e n t a g e o f G r a v e l

Dre

dge

Pum

ping

Rat

e, c

ubic

met

ers/

hour

Figure 13: UNVERIFIABLE PERFORMANCE (Downtime)

0

5

10

TBM Downtime Categories

Tota

l Dow

ntim

e,

mon

ths Claimed Encountered

Figure 14: DIFFERENCE IN PERFORMANCE (Rate/3-D Surface)




Figure 15: NO DIFFERENCE IN PERFORMANCE (Dredge Capacity)

0%

27%

73%

0%

27%73%

0

500

1,000

1,500

0% 10% 20% 30% 40% 50% 60% 70% 80%Gravel/Sand Content

Dre

dge

Pum

ping

Rat

e, c

ubic

met

ers/

hour

Unreasonable Anticipated Capacity Actual Capacity




Figure 16: STABILITY, CONSTRUCTION DISTURBANCE, AND CONSEQUENCES




Figure 17: CAUSE AND EFFECT RELATIONSHIP (Quartz Content-Penetration Rate)

0

5

10

15

0% 25% 50% 75% 100%

Quartz Content

TBM

Pen

etra

tion

Rat

e, m

/hr

Figure 18: CAUSE AND EFFECT RELATIONSHIP (UCS-Drill Rate)

y = 4.7175e-0.0135x

R2 = 0.5625

0.0

1.0

2.0

3.0

4.0

5.0

0 50 100 150 200 250Uniaxial Compressive Strength, MPa

Dril

ling

Rat

e, m

/hr

Anticipated AverageEncountered Encountered AverageEncountered (Correlation Curve)

Figure 19: NO CAUSE AND EFFECT RELATIONSHIP (Weekly Inflow)

0

5,000

10,000

15,000

20,000

25,000

0 50 100 150 200

Inflow, Litres/minute

Wee

kly

Adv

ance

, met

ers




Figure 20: NO CAUSE AND EFFECT RELATIONSHIP (Daily Inflow)

0

10

20

30

40

50

60

70

0

200

400

600

800

1000

1200

1400

1600

1800

2000

W eir Flow , l/m inute

Dai

ly E

xcav

atio

n A

dvan

ce, m

Figure 21: IMPACT OF OVERBREAK (Time-Progress)

Cumulative Shifts

Sta

tion,

ft

0

1000

2000

3000

4000

5000

50 100

150

200

250

0

200

400

600

800

Ove

rbre

ak, c

u in

Anticipated Encountered Series3

Figure 22: IMPACT OF OVERBREAK (MMSD - Labor Efficiency)

Exc

avat

ion

Labo

r, m

an h

rs/ft

0 .00

2.00

4.00

6.00

8.00

10.00As Anticipated Fallout Zone #1 Fallout Zone #2




Figure 23: NO ADVERSE IMPACT (Dredging Gravel)

Time, days

Exc

avat

ion

Cos

t, $/

CY

0.25

0.3

250 300 350

||

||

Gravel

Figure 24: EQUIPMENT CONDITION (Pump Efficiency)

0%

25%

50%

75%

100%

0 50 100

150

200

250

300

350

400

450

500

550

Cumulative Dredging Time, days

Hyd

raul

ic P

ump

Effic

ienc

y

Anticipated AverageEncounteredEncountered Average

Technical Elements for the Presentation and Evaluation of Diffrering Site Condition Claims ……….….……. 26-Dec-12 / Page 106



10. APPENDICES




Appendix A: Forms for Effective Documentation of Encountered Conditions and Construction Performance




FORM 1: ROCK TUNNEL GEOLOGICAL LOG




FORM 2: TBM PERFORMANCE SHIFT REPORT TBM Excavation - Shift Report - Page 1 DATE: ______________________ Project: _________________________________ Day Shift: __ From ____ to ____ Contractor: _________________________________ Sw Shift: __ From ____ to ____ Gr Shift: __ From ____ to _____ CLOCK: BEGIN ______________ END _______________ HOURS ________ FACE STATION: BEGIN ______________ END _______________ FEET _________ TARGET: BEGIN SHIFT LUNCH END SHIFT

Clock Time

Total Time

ACTIVITY / List ALL detailed activities performed while the TBM is not mining;

Cutter Drive Motor Amperage

Propel Pressure

From To min Provide start/end time for each period Avg Max Avg Max




TBM Excavation - Shift Report - Page 2 Date _____________ Shift __________ Report # _______ FACE CONDITIONS BEGIN SHIFT LUNCH END SHIFT

Station ________ Station _______ Station _______ material __________________ material __________________ material __________________ water, gpm _______________ water, gpm _______________ water, gpm _______________ dust ____________________ dust ____________________ dust ____________________

TBM Clock Station @

Face Cutter

Position Cutter Type Hub Number Reason for Change

Describe in Detail Old New Material Count

Ribs Bolts Epoxy Cartridges

Wire Mesh

Straps Dowels Track Air Line

Fan Line Discharge Line

Water Line

XXXX

Heading Crew

Walker Shifter TBM Operator

Mechanic Electrician Engineer Conveyor Operator

Oilier Miner Labor

Pump Operator

XXXXX

Train Motormen Brakemen Bull Gang

Foremen Laborers

XXXXX

COMMENTS & INSTRUCTIONS FOR NEXT SHIFT _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

REPORT PREPARED BY ________________________________________________________________________________________________




FORM 3: PILE SOCKET DRILLING REPORT Date: ___/____/___ Shift Begin: ______ Pile #: _____ Report #: _____ Shift End: ______ Foreman: ______________________ Operator: ________________________ Move / Setup Start Move (time): _______ End (time): ______ Duration: ______min Start Setup (time): _______ End (time): ______ Duration: ______min Overburden Drilling Start Drill (time): _______ End (time): _____ Duration: ______min Rock Drilling Start Drill (time): _______ Drill (time): ______ Drill Duration: ______min Equipment Used: _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________ Comments: _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Pile Length, m: ________ Drilling Start Depth, m: _____ Centralizer Length, m: ________ Depth @ End of Drilling, m: _____ Centralizer Length (below tip),m: ________ Depth of Overburden, m: _____ Required Socket Length, meters: ________ Actual Socket Length, meters: ________




Date: ___/____/___ Shift Begin: ______ Pile #: _____ Report #: _____ Shift End: ______ Foreman: ______________________ Operator: ________________________

Beginning

Time: Ending Time:

Duration, minutes

Activity / Drilling/ Downtime (provided details) PLEASE ACCOUNT FOR ALL TIME

Code




FORM 4: PIPE JACKING REPORT Pipe Jacking Shift Report - Page 1 Date: ____________ Day: ________ Project: _______________________________________ Day Shift ________ From ________ to __________ Contractor: ________________________________ Sw Shift ________ From ________ to __________ Grv Shift ________ From ________ to __________ General Contractor:_________________________________ Pipe: ID: _________ in OD: ____ in Location: _________________________________ Owner: ________________________________________ Job: Name: _________________________________ No: ___________________________________________

Time

Total Time

ACTIVITY / List ALL detailed activities performed while the Excavation is / is not

progressing;

Grout Pumped

# of

Jacks

Propel Pressure

From To min Provide start/end time for each period Bags Water Avg Max

MACHINE CLOCK: BEGIN ______________ END _______________ Machine Time: ________ hrs FACE STATION: BEGIN ______________ END _______________ Length Jacked: ______ ft TARGET: BEGIN SHIFT LUNCH END SHIFT




Pipe Jacking Shift Report - Page 2 Date _______ Shift _______ Report # ___

FACE CONDITIONS

BEGIN SHIFT LUNCH END SHIFT water _________ gpm water _________ gpm water _________ gpm dust _________ dust _________ dust _________

Material Count

Ribs Bolts Epoxy Cartridges

Wire Mesh Straps Dowels Track Air Line Fan Line Discharge Line

Water Line

XXXX

Heading Crew

Walker Shifter Operator Mechanic Electrician Engineer Conveyor Operator

Oilier Miner Labor

Pump Operator

XXXXX Train Motormen Brakemen Bull

Gang Foremen Laborers

XXXXX Time: Bulkhead Down:_____________________Excavation & Jacking: ____________________ Bulkhead Up: ___________________ Start Grout Time End Grout Time Total Grout Time Grout Volume Grout Type

Name of Employee Labor

Trade Hours Worked

From To Total Equipment Number Hours Worked

From To Total

Summary of Work: __________________________________________________________________________________________________________________________________________________________________________________________________________________________

COMMENTS & INSTRUCTIONS FOR NEXT SHIFT ________________________________________________________________________________________________________________________________________________________________________________________________

REPORT PREPARED BY: ___________________________________ Signature:_____________________________________




FORM 5: SOFT GROUND EXCAVATION REPORT CONTRACTOR: ___________________ PROJECT: ______________ Report #: ____________ DAY ______ DATE _____________ SHIFT: Day _____ Swing _____ Graveyard _____ CLOCK: BEGIN _____________ END ________________ HOURS ______________ FACE STATION: BEGIN _____________ END ________________ FEET ______________ AMPS (avg): BEGIN SHIFT _____________ LUNCH ________________ END ______________ PROPEL (avg): BEGIN SHIFT _____________ LUNCH ________________ END ______________ TARGET: BEGIN SHIFT LUNCH END SHIFT _____ _____ _____ |__|__| |__|__| |__|__| |__|__| |__|__| |__|__| REMARKS ____________________________________________________________

ACCOUNT FOR TIME Account for all Time Explanation of Activity

From To Duration, minutes

(report time duration for each activity)




SOFT GROUND EXCAVATION REPORT - Page 2 FACE Station & Conditions: Report Number: ______ BEGIN SHIFT LUNCH END SHIFT

Station ____________ Station ____________ Station ____________ water _________ gpm water _________ gpm water _________ gpm dust ______________ dust ______________ dust ______________ material ___________ material ___________ material ___________

MATERIAL COUNT: Ribs ______ Bolts _______ Dowels ______ Wire Mesh _______ Straps ______ Cartridges ________ Lagging __________ Segments __________ Air Line _____ Fan Line _____ Dischg _______ Track ________ Water Line _____ HEADING Labor: Walker ____ Shifter ____ TBM Op ___ Mechanic ____ Electr ____ Engnr ____ Conv Op ___ Miners/Lbr ___ Oiler ___ PumpOp ____ TRAIN: Motorman ____ Brakeman ____ BULL GANG: Foreman ___ Laborers ____ COMMENTS: ______________________________________________________________________ ____________________________________________________________________________________________________________________________________________ ______________________________________________________________________ INSTRUCTIONS FOR NEXT SHIFT: ________________________________________ ______________________________________________________________________ ______________________________________________________________________ REPORT ACKNOWLEDGMENT: Date: ______ SHIFT: Day ___ Swng __ Grave _____ Walker: ___________________________ Shifter: _____________________________ Operator: ____________________________ Engineer: _________________________

Appendix B: The Stuff That Claims Are Made Of

Differing Site Condition Claims: Technical Analysis ... · Risk ... evaluation of entitlement in...

Documents

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