C&SM_Notes-I

8/2/2019 C&SM_Notes-I

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CONSTRUCTION & SITE

MANAGEMENT- NOTES-I

Management is an art & technique of applying Techno-economic principles to the available resources to

achieve the desired goal in an organization in the most efficient manner.

Project Mgmt. is the way to manage the whole or part of an entire project that are limited in scope &

time. The primary objective of the project Mgmt. is to finish the project within the scheduled time and

budgeted cost & at the same time achieve good quality & workmanship.

Four main Objectives Of Constn. Mgmt.:

1.Time

2. Cost

3.Quality.

4.Safety

Responsibilities of a Construction Manager:

most common responsibilities of a Construction Manager fall into the following 7 categories:

Project Management Planning, Cost Management, Time Management, Quality Management, ContractAdministration, Safety Management, and CM Professional Practice which includes specific activities like

defining the responsibilities and management structure of the project management team, organizing andleading by implementing project controls, defining roles and responsibilities and developing

communication protocols, and identifying elements of project design and construction likely to give riseto disputes and claims.

Project management has the following three phases.

i) Planning ii) Scheduling & iii) Controlling.

PLANNING

Planning is the most important part of Project management. Project plan defines the scope of the

project. It determines gross requirements of resources and the ways as to how the project will

proceed towards satisfactory completion. It essentially tells “What to Do” & “ How to Do it”It has three main objectives

1. Project should be Completed in estimated Time.

2. It should use available manpower & resources as minimum as possible.

3. It should be completed in minimum Capital investments.It comprises of Time Plan, Resources Plan & Plan for controlling.

Planning Provides

• Direction as to how the Project is to be run.• Unified frame Work of Goals , Activities & Individuals.

• Helps to reveal future opportunities & threats.

• Performance standards for measuring progress & Quality.

SCHEDULING

Scheduling is the allocation of resources. It validates time objectives & shows planned sequence

of activities with starting & Completion dates. It tells “when to Do it”

It plays great role in completing the project in Time.

It helps in economic employment of resources.It brings out implications of Time & resources constraints.

It enables forecasting of input resources.

Type of Schedules

1. Material Schedule



2. Labor Schedule

3. Equipment Schedule4. Finance schedule

CONTROLING

It is monitoring the progress achieved in comparison with planned program to determine the

deviations so that re planning & rescheduling can be done to offset the deviations.

Aims of Controlling1. To check the quality of work against scheduled Specifications.

2. To check physical progress of each activity as per Time schedule.

3. To control on use of Machine, Material & Labor output to avoid wastage.4. To control the expenditure on each item of work so as to complete the project as per cost estimate.

Controlling is done at 4 Levels

With distinctive objectives & methods.

1. Operational Control : at Supervisory level.2. Administrative Control : at Managerial Level.

3. Directional Control : at G. M./Project Manager Level.4. Strategic Control : at Corporate Level.

The planning & scheduling phases of a project are undertaken before the actual project starts while the

controlling phase is undertaken during the actual project operations.

TOOLS OR TECHNIQUES OF PROJECT MANAGEMENT.

BAR CHART

Bar Chart is a graphical representation of various activities on a time scale. It consists of twocoordinate axes, activities on Y-axis & time required to complete on X- axis. The length of the bar showsthe time required to complete the activity. It was invented by Henry Gantt in 1900,hence it is also called

“Gantt Chart”.

Advantages of Bar Chart: -

i) It’s very simple to make & easy to use.

ii) It’s suitable for small projects.iii) It can be modified to show current progress against planned one.

iv) It is easily understood by all.

Limitations of Bar Chart

1. Interdependencies of Activity: It does not show Interdependencies of Activities.2. Project Progress:- It does not show progress of work hence cannot be used as efficient Control

device.

3. Quantities of items: It depicts Time schedule for various activities but does not indicate Quantity

of work.4. Critical Activities:- It does not indicate critical activities requiring careful attention.

However Bar chart can be modified to depict the progress by showing the progress of each activity, byhatched lines along the corresponding bar of that activity.



Milestone Chart

Bar charts were later modified in to Milestone charts.

Bar chart represents the Activities while Milestone chart represents the Events which mark either the

beginning or the end of activity. The bar of the Bar chart is broken onto a no. of pieces, each one of

which represent major event. Though controlling is better achieved than bar chart, it has the samedrawback of Inter-dependence between the events.

Network Method

Network diagram is an outcome of the improvements in the milestone charts, which removes the above

deficiencies. Network technique provide a rational approach to the planning & controlling of constructionworks. This technique is based on the basic characteristics of all projects, that all work must be done in

well defined steps. The network technique represents the steps of the project objective graphically in the

form of a network or arrow diagram. The two commonly used network techniques are CPM & PERT.

Advantages of Network Technique

1. Detailed and thoughtful planning provides better analysis and logical thinking.

2. Identifies the critical activities and focus them to provide greater managerial attention.

3. Network technique enables to forecast project duration more accurately.4. It is a powerful tool for optimization of resources by using the concept of slack.

5. It provides a scientific basis for monitoring, review and control, to evaluate effect of slippages.

6. It helps in taking decisions (i) to over-come delays, (ii) on crashing programme, (iii) for optimizing

resources, and (iv) on other corrective actions.7. It helps in getting better co-ordination amongst related fields.

8. It is an effective management tool through a common and simple language, providing common

understanding.

CPM:

CPM was developed in 1956 in USA by a team of Engineers & was successfully tried for the Construction

of a chemical plant. Presently this method is widely used world wide in business & industry.

In India CPM is being increasingly used for project management by a number of private & public

organizations. CPM provides meaningful answers to the following questions.

I. What will be completion Time of project?

II. If there is a delay in one activity, will the entire project be delayed & if so, by much ?

III. What how is the most economical way to speed up the project?IV. How to schedule materials deliveries so as to have it ready when needed but avoid costly storage

for long periods.

CPM network is referred to as activity oriented diagram in which each activity is represented by

an arrow & the sequence in which the activities are performed is shown by the sequence of the

arrows.Application of CPM results in better decisions & a saving in over all cost. It is generally used for

repetitive type projects for which fairly accurate estimate of time for completion of each activity



can be made. It is very useful for construction projects but not suitable for Research &

Development projects.

PERT

PERT stands for Program Evaluation & Review Technique. This method was developed by

Engineers of U.S. Navy for working on the polaris Missile programme during 1957-58.

PERT uses a network diagram consisting of events which must be established to reach the projecobjectives. It uses event oriented network diagrams in which successive events are joined by

arrows. It is more suited for various Research & Development projects which are non repetitive in

nature. Such projects are characterized by extreme degree of uncertainly. Where no previousknowledge of time estimate is available. It is a time oriented technique in which three times

estimates are used to determine the expected or average time of each activity. The expected time

forms the basis of PERT networks.

Computation of Expected Time (te)

I. Optimistic Time Estimate (to) is the shortest possible time for completing an activity if

everything proceeds as planned without any problem (ie in ideal condition)II. Most Likely Time Estimate (tl) is the time for completing an activity under norma

conditions. In this case, conditions are not ideal & minor problems may come.III. Pessimistic Time Estimate (t p) is the maximum time required to complete an activity under

abnormal or extremely adverse conditions in which everything goes wrong. The estimate

however does not include catastrophes such as fires, earthquakes, floods etc.

Te = to + 4tl + t p6

COMPARISON

CPM PERT



1.

CPM is activity oriented 1.

PERT is event oriented

2

.

Single time estimates are used

for the various activities.

2

.

Time Estimates for activities are

probabilistic. Following three types

of estimates are used for eachactivity.

i. Optimistic Time

ii. Pessimistic Timeiii. Likely Time

3

.

CPM is used for repetitive types of

projects where the time estimates for various activities are either known or

can be determined fairly accurately.

3

.

PERT is used for pioneering type of

projects where prior data aboutactivity times is not available.

4

.

CPM places emphasis on optimizing

allocation of resources & minimizing

overall project cost.

4

.

PERT places emphasis on reducing

project completion time without cost

constraint.

Advantages of Critical Path Method

Some of the important advantages are summarized here:

• It helps in ascertaining time schedules.

• With its help, control by the management becomes easy.

• It makes better and detailed planning possible, drawing the manpower schedule, material schedule

and cash flow schedule.

• It encourages discipline.

• It provides a standard method for communicating project plans, schedules and cost performance.

• It identifies most critical elements and thus more attention can be paid on these activities.

The CPM technique requires greater planning than required otherwise. Thus, this method increases the

planning cost but this cost can easily be justified by concentrating attention on critical paths only andavoiding unnecessary expenses on the strict supervision over the whole programme. This helps the

management to divert the resources from non-critical activities to the critical activities.

Drawbacks of CPM

• Assumption of time for the activities in the project may not be true during project execution.

• After every change, it is necessary to re-evaluate the project and new critical path is found.

Terminology

1. Activity: - Performance of a specific task, operation, job or function which consumes time &

resources & has a definite beginning & end is called an activity.



2. Event: - The commencement or completion of an activity is called an event. An event consumes

no time or resources and is denoted by nodes, circular or rectangular.3. Network : - A network is the diagrammatic representation of a work plan showing activities step by

step, leading to the established goal and depicting the inter-dependence between various activities.

4. Direct Cost: The cost incurred on resources like Material, labor & Machinery consumables whichare directly used in the construction is called Direct cost.

5. Indirect Cost: The cost incurred on Site facilities, Hiring & maintenance of Equipments

Administration & outages: interest, penalties is called Indirect cost.

6. Critical Activity: The activity with zero float meaning the delay in it’s Start Date or Finish Datecan delay the entire Project is called Critical activity.

7. Serial Activities: The activities which are in sequence, one after another.

8. Parallel Activities: Activities which can be performed concurrently are called parallel activities.9. Predecessor Activity: The activity which comes before the activity in consideration.

10. Successor Activity: The activity which follows the activity in consideration.

11. Dummy : Which does not require resources & time. It merely shows dependence of activities in Network & is shown in dotted line.

12. Critical Path: The Longest path in Network which runs through critical activities denoting the

duration of the Project.13. Earliest Start Time- EST: - It is Earliest Time when an activity can start.

14. Earliest Finish Time- EFT:- It is Earliest Time when an activity can be finished.15. Latest Start Time- LST: - It is Latest time when activity may be started withou

delaying the project.16. Latest Finish Time- LFT: - It is Latest time when activity may be finished without delaying the

project.

17. Float (slack)

i.) Total Float: - Maximum Time by which activity can be delayed without delaying

the project. = (Latest finish time – Earliest finish time)= (Latest start time – Earliest start time)

ii.) Free Float: - It is difference between EST of succeeding activity & EFT of the

considered activity.iii.) Independent Float: - Excess of Minimum available time over the activity duration.

18. Earliest Expected Time (TE): - It is the earliest expected completion time of the project and is

equal to the sum of expected time (te) of all the activities along the longest path of the project.19. Latest Allowable Time (TL): - It is the largest possible time, an event can take without delaying

the final completion date.

Normal Time (Tn): - It is the standard time for Performing an activity as allowed by Estimator.

Normal Cost (Cn):- It is minimum direct cost when the activity is performed in normal time

. duration.

Crash Time (Tc): - It is the minimum time in which an activity can be performed.Crash Cost (Cc): - It is the minimum direct cost required to achieve the target date as per crash

program & directly related to the crash time.

Two Systems are used for Network Representation.

1) A-O-A



2) A-O-N

AOA- Activity on Arrow system.

In this system an activity is graphically represented by an arrow from left to right. The description of theactivity is written above the arrow & the time taken to complete the activity is written below it. The length

of arrow beares no relationships to the duration of the activity it represents.

Fix Shuttering

4 Days

Pour Concrete

2 (Days)

An event is graphically represented by a number enclosed in circle. The beginning of activity is marked by‘tail event’ & the end by head event.

A-O-N— Activity on Node system.

In this system activities are represented on the nodes & arrows are used to show the dependencyrelationship between the activity nodes

Time required to complete an activity is also indicated in the node.



A- Shuttering

B- Procure Material

C- Fix Reinf.

D- Casting Start

Rules for Developing Network

1. Rule- I No Activity can commence until all preceding activities have been completed.

2. Rule- 2

A ‘dummy activity’ is introduced in the Network either to show dependency or to avoid duplicate

numbering of activities. It is artificial activity shown in dotted line.

3. Rule- 3

The logical placement of an activity in the network is governed by the following three

considerations.

i. Which activities must be completed before this activity can commence? (Precedence)ii. Which activity can be carried out along with this activity (Concurrence)

iii. Which activity cannot commence until this activity is completed? (Subsequence)

4. Rule-4 No activity should lead back to a previous event ie, there must not be any “looping”

5. Rule-5

In any network, there must be only one start & one finish (with any no of activities between ie no

activity should be left dangling)

How to Draw the Network Diagram

Before starting to draw the network, following measures should be taken serially:

1. Prepare a list of the activities included in the project.

2. Arrange them in a sequence based on their dependencies on other activities.

Start

A

3

C

2

B

2

D

1



3. Prepare estimate of time required for each activity, considering manpower and equipments

available and in certain cases assumptions are based on statistical approach and experience.4. These time estimates are then written on each activity.

5. Draft the network roughly, usually by soft pencil and an eraser on a large piece of paper.

6. The scheduling computations are done to get earliest and latest allowable start and finish times foreach activity,

7. Draw critical path and indicate the amount of slack on non-critical paths.

8. Now this is prepared in final form for use in the field

9. While drawing the network diagram, following points should be taken care:(a) Criss -crossing should be avoided, as far as possible.

(b) Try to keep arrows aligned in straight lines.

(c) Try to keep large angles between activities.(d) Try to minimize dummies.

(e) A network should start at a single node and terminate at a single node only.

10. Project is controlled by checking the progress against the schedule.

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