Construction Inspection of Concrete Dams and Spillway

Inspection of Construction of Concrete Dams & Spillways

Autoridad del Canal de Panama (ACP) 1

Day 2 - Session 4Construction Inspection Best

Practices


Construction Inspection Best Practices

• Initial Inspection

• Daily Reports

• Inspection Checklists

• Worksheets

• Construction Closeout

• Open Discussion


Initial Inspection

• Prior to beginning work:– Contractor must receive signed NTP– Approved safety officer and safety plan– Safety meeting must be conducted prior to

beginning work– At least one person from each foreman’s crew

must hold a current first-aid card– Hard hat sign must be prominently displayed

at all construction site entrances


Initial Inspection

• Prior to beginning work: (continued)– A National Pollution Discharge Elimination

System (NPDES) permit notice poster must typically be prominently displayed at all construction site entrances

– Stormwater Pollution Prevention Plan (SWPPP) must be implemented and other NPDES requirements addressed


Initial Inspection

• Prior to beginning work: (continued)– Emergency contact information must be

posted on the contractor’s bulletin board– Sanitation facilities must be operational – Utilities and existing works must be identified

and protected – Utility owners must be notified whenever there

are utilities in the area that may be affected by the construction activity


Daily Reports

• One of the most overlooked parts of construction inspection

• Inspector’s primary responsibility is to verify work is being completed according to the specifications

• Primary importance of inspector’s daily report is to advise supervisors of the day’s work and to report pay quantities


Daily Reports

• Daily reports should be:– Clear– Effective– Factual– Readable– Usable by others

• Will be reviewed by people who are not there, not on the job


Daily Reports

• Properly Document:– Construction Activities– Procedures– Schedules– Materials– Quantities– Test Results– Problems– Other


Daily Reports

• Purpose:– Inform supervisor– Inform other inspectors– Calculating payments– Settling claims– Closing out contract– Review of structural failures– Design process of future projects


Daily Report

• Use “concrete terms” and “lowest rung on the ladder”

• Abstraction ladder example

pipe

metal pipe

corrugated metal pipe

600-mm diameter corrugated metal pipe

600-mm diameter corrugated metal pipe, No. 16-gage


Daily Reports

General Terms

“Poor weather conditions” could mean rain, or it could mean snow, or even intense heat. It could mean any variations between these extremes. So in describing the weather, you should say specifically what kind of weather was experienced; such as “rain started to fall at 11 a.m. and continued steadily for two hours. The sun broke through at 1:30 p.m. The temperature was about 28 degrees for the rest of the day.”


Daily Reports

General Terms

The workforce started the day late and didn’t really get much done. For some reason the pump broke and that caused us some problems. The foreman added more men to the already large crew to help with the pump problem. The weather didn’t help either; it was bad.


The workforce started the day late and didn’t really get much done. For some reason the pump broke and that caused us some problems. The foreman added more men to the already large crew to help with the pump problem. The weather didn’t help either; it was bad.

Daily Reports

General Terms


Daily Reports

• Organize your thoughts

• Daily reports must be clear and simple

• Writing must be simple, direct and easy to understand

• Avoid being indirect and wordy

• First step – systematic organization of your thinking

• Fix your ideas in your own mindAutoridad del Canal de Panama (ACP) 15

Daily Reports

WHO – WHAT – WHERE – WHEN – HOW

EQUIPMENT – WEATHER - SAFETY


Daily Reports


Daily Reports

• Communications with the Contractor– What did the contractor complain about?– What questions did the contractor ask me?– What did I tell the contractor?


Daily Reports


Daily Reports

• Manpower & Equipment Report


Daily Reports• Drilling Report


Daily Reports• Water Pressure Test Report


Daily Reports• Grouting Report


Daily Reports• Grouting Record Plot


Daily Reports

• Photographs– Unusual conditions or situations– Completed projects– Dated & location noted (photographer name)– Include person or object for scale– Changed conditions, damaged equipment or

materials– General work progress periodically– Captions required in reports


Inspection Checklists

• Assist inspectors in performing inspections

• May not include all items

• Provide guidance only

• Not a comprehensive list

• Customize for each project and specs

• Document in daily report when checklist is completed



• Examples checklists included in workbook– Quality Assurance Inspection– Construction Safety– Construction Surveying– Quantity Computations– Construction Erosion and Pollution Control– Foundation Preparation– Removal of Water– Excavation– RCC Construction



Concrete Forms



Reinforcement



Finishing Concrete Surfaces



Joints & Waterstops



Curing Concrete


Inspection Checklist

RCC Construction


Inspection ChecklistSpillway Gates


Concrete ConstructionRecords and Reports


• Documents to place in contract files:– Mix Computations

• Trial mix computations and adjustments• Selection of job mixture

– Batching and mixing records• Records of daily batching operations• Summary of batching and mixing records• Summary of volume of each class placed



• Documents to place in contract files:– Placing and Curing Records

• Amount of concrete placed in individual parts of the structures each day

• Time curing medium was applied, forms were removed, defective surfaces were repaired and curing was applied



• Documents to place in contract files:– Strength Tests

• Reference test results report in job diary• Report numbers assigned to all test specimens

shipped to the laboratory• Report location and amount of concrete

represented by each strength test



• Documents to place in contract files:– Inplace concrete

• Further tests may be needed If tests indicate inadequate concrete compressive strength

• Core samples from structure• “Swiss Hammer” can help determine extent of

questionable concrete • Do not use to determine strength for acceptance or

earliest time forms can be stripped

Worksheets

• Designed to assist inspectors

• Document in daily report when worksheet is completed

• Include worksheet with daily report

• Examples:– NRCS NEH Part 645 App A– USACE Quality Assurance Representatives

Guide EP 415-1-261


Worksheets


Site Cleanup

• Worksite and surrounding areas used by contractor kept in orderly condition at all times during work

• All areas properly restored before the completed work is accepted

• Cleanup requirements are stated in the contract


Site Cleanup

• Plant, buildings, unused materials, cleared material and other debris – removed from site

• Access and haul roads – appropriately restored

• Fences, utilities and other facilities temporarily removed - restored


Construction Closeout

• Records and materials– Name, make, and model number of each piece of

equipment– All equipment test records– Approved shop drawings– Operating and maintenance instructions– Spare parts and tools– Keys– Guarantees with required contact and expiration date– Record Drawings


Open Discussion


Acknowledgements

• Natural Resource Conservation Service– National Engineering Handbook Part 645 –

Construction Inspection– National Engineering Handbook Section 19 –

Construction Inspection


Acknowledgements

• U.S. Bureau of Reclamation– Construction Inspector Training Program

• U.S. Army Corps of Engineers– Quality Assurance Representative's Guide

EP 415-1-261 (Vol 1-5)


Construction Inspection of Concrete Dams and Spillway

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