CONSTRUCTION PLANNING

Planning can be defined as ‘drawing up a method

or scheme of acting, doing, proceeding, making,

etc., developed in advance.

Construction projects involve using different

resources—human, equipment and material,

money, etc., and at all times.

The task of a construction planner is to draw up

plans for optimum utilization of all these resources

and to ensure appropriate preparedness at all

times.

construction of a large project involves diverse

agencies—government regulators, clients/owners,

designers, consultants and contractors.

it is important to ensure proper coordination to

ensure that the agencies do not work at cross-

purposes, and that the common goal is served.

It should be noted that plans are drawn up at each

of the stages or phases of a project, though

different terminologies are used at times depending

upon the stage of the project

Ex:- feasibility plan, preliminary plan etc.

initially when the project is at the inception stage,

the plan could be referred to as a feasibility plan,

while in the engineering and execution stages,

terms such as preliminary plan and construction

plan, respectively, are commonly used.

Some of the activities involved in construction planning are:

Defining the scope of work:

Since all activities involve consumption of different resources to different extents, it is important that the scope of work involved is properly and, to the extent possible, completely defined. Any addition, deletion, or modification in the scope could have serious repercussions in terms of time of completion and cost etc.

For example, if felling trees and getting environment clearances is added (at a later date) to the scope of a contractor who has been awarded a job for construction of roads, it would obviously cause difficulties.

Identifying activities involved:

This part of planning is very closely linked to defining

the scope, and involves identifying activities in a

particular job.

Since different activities involved consume different

physical resources to varying extents, it is crucial that

these activities are exhaustively listed, along with the

resources required.

For example, though different agencies may be

concerned with ‘environmental impact assessment’, it is

important for them to identify the tools or parameters

each will be using so as to plan effectively.

Establishing project duration

This can be done only with a clear knowledge of the

required resources, productivities and interrelationships.

This information is used to prepare a network and other

forms of representations outlining the schedules.

Duration for an activity normally depends on amount of

resources allocated to it and can be increased or

decreased.

Defining procedures for controlling and assigning

resources:

It is important that the planning document prepared is

followed by others involved in the execution of the

project, or in its individual phases.

Thus, the procedures to be followed for procurement

and control of resources for different activities—

manpower, machines, material and money—are also

laid down.

Developing appropriate interfaces:

The planner needs to devise an appropriate system for

management information system (MIS) reporting.

Tools such as computers and formats for reporting are

widely used, and it may be noted that several software

are readily available to aid the planner

Updating and revising plans:

a construction plan needs to be continuously updated

and revised during monitoring

the planner should clearly understand the product to be produced

in terms of scope and expected performance, the input required

and the process involved, including the issues in quality control

and tolerances at different steps.

At the same time, the time and productivity aspects involved in

the different activities should also be understood, besides the

interdependence of activities.

The planning should also identify milestones and targets for the

different agencies to facilitate proper monitoring during execution.

Inclusion of features identifying risks associated with a project,

and the appropriate responses for mitigation enhance the quality

of the project plan.

TYPES OF PROJECT PLANS

Schedule, cost, quality and safety can be identified

as specific items on which the success of any

(construction) project is evaluated.

Thus, at times it makes sense to have different

plans for each of these criteria—and draw up

(separately) a time plan (or schedule), cost plan,

quality plan and safety plan.

depending upon the nature and stage of the project,

one may also need to deal with a plant and

equipment plan, a maintenance plan and a staff

deployment plan.

TIME PLAN

Time is the essence of all construction projects, and contracts often have clauses outlining awards (bonus payments) or penalties (as liquidated damages) for completing a work ahead or later than a scheduled date.

While effort is made to ensure timely completion of work, it should be noted that some of the common reasons for delays could be a sluggish approach during planning, delay in award of contract, changes during execution, alterations in scope of work, delay in payments, slow decision-making, delay in supply of drawings and materials, and labour trouble.

Several reasonably well-established techniques are

available and commonly used for time planning (or

‘scheduling’) activities—for example, critical path

method (CPM), programme evaluation and review

technique (PERT), precedence network analysis

(PNA) etc.

The choice of the method to be used in a particular

case depends on the intended objective, the nature

of the project, the target audience, etc.

MANPOWER PLAN

This plan focuses on estimating the size of

workforce, division in functional teams and

scheduling the deployment of manpower.

It may be noted that manpower planning also

involves establishing labour productivity standards,

providing suitable environment and financial

incentives for optimum productivity, and grouping

the manpower in suitable functional teams in order

to get the optimum utilization.

MATERIAL PLAN

The material plan involves identification of required

materials, estimation of required quantities, defining

specification and forecasting material requirement,

besides identification of appropriate source(s),

inventory control, procurement plans and

monitoring the usage of materials.

CONSTRUCTION EQUIPMENT PLAN

Modern construction is highly mechanized and the role

of heavy equipment in ensuring timely completion of

projects cannot be over-emphasised. Machines are

used in modern construction for mass excavation,

trenching, compacting, grading, hoisting, concreting,

drilling, material handling, etc. Induction of modern

equipments could improve productivity and quality,

besides reducing cost. At the same time, it should be

borne in mind that heavy equipments are very costly

and should be optimally utilized in order to be

productive. It is also important that the characteristics of

equipment are kept in mind when drawing up an

equipment plan.

FINANCE PLAN

Given the fact that large construction projects require huge

investments, and a long time to complete, it is obvious that

all the money is not required at any one point in time.

Contractors fund their projects from their working capital, a

part of which is raised by the contractors using their own

sources (e.g., bank loans secured against assets,

deployment of resources from their inventory).

Whereas the rest comes from a combination of avenues

such as mobilization advance for the project, running-

account bills paid by the client, secured advances against

materials brought at site, advance payments, and credits

from suppliers against work done.

Thus, a careful analysis needs to be carried out to determine

how the requirement of funds varies with time.

WORK-BREAKDOWN STRUCTURE

‘Work-breakdown structure’ (or WBS), or simply

‘work breakdown’, is the name given to a technique

in project management in which the project is

broken down into manageable parts.

WBS represents ‘a task-oriented “family tree” of

activities and organizes, defines, and graphically

displays the total work to be accomplished in order

to achieve the final objectives of the project.’

This provides a central organizing concept for the

project and serves as a common framework for

other exercises such as planning, scheduling, cost

estimating, budgeting, configuring, monitoring,

reporting, directing and controlling the entire

project. Thus, it should be intuitively clear that for a

complex project, greater care is required in

formulating a successful WBS.

A work-breakdown structure (usually triangular in

shape) progresses downwards in the sense that it

works from pursuing general to specific

objectives—much like a family tree, it provides a

framework for converting a project’s objectives into

specific deliverables.

In cases of complex projects the power and utility of

the WBS method in effective management of the

work is clearly demonstrated

METHODOLOGY OF WBS

A project is split into different levels from top to bottom

The WBS does not go into the details of activity at the

operational level. The term ‘subprojects’, ‘work

packages’, and ‘tasks’ are used interchangeably

The tasks are broken down into activities that are the

lowest level of a work-breakdown structure.

It should be borne in mind that once this breakdown is

exhaustive, operations such as development of the time

schedules, resource allocation and project monitoring

become simplified.

PROJECT PLANNING TECHNIQUES—

TERMINOLOGIES USED

Event and Activity

Event is a point in time when certain conditions have been fulfilled, such as the start or completion of one or more activities. An event consumes neither time nor any other resource. Hence, it only expresses a state of system/project.

Activities take place between events. Activity is an item of work involving consumption of a finite quantity of resources and it produces quantitative results. An exception to this rule is the dummy activity

Ex: activity i-j. The start (node i) and the completion (node j) of this activity can be considered as events.

Dummy Activity

This activity does not involve consumption of

resources, and therefore does not need any time to

be ‘completed’. It is used to define interdependence

between activities and included in a network for

logical and mathematical reasons.

Network

Precedence:

This is the logical relationship implying that an activity

needs one activity (or more activities) to be completed,

before this activity can start.

For example, in order to be able to start plastering, the

brickwork needs to have been completed

It is a common practice in most construction projects to

represent the precedence of activities in the form of a

table, called the precedence table.

For preparing the precedence table, a list of activities

that should precede a given activity is given.

It should also be mentioned that this concept (of

precedence) is sometimes referred to as ‘dependence’.

NETWORK LOGIC

DURATION OF AN ACTIVITY

Duration of an activity (i, j) is denoted by D(i, j). This

is the length of time required to carry out an activity

(i, j) from the beginning to its end.

Depending upon the activity and the level of detail,

the duration may be expressed in days, weeks, or

months.

a duration cannot be really fixed or given as a final

number, and as such remains only an estimate,

based on past experience with productivity, etc

START AND FINISH TIMES

In principle, an activity can be started as soon as

the groundwork involved has been completed, but

the client or contractor may (be able to) wait for

sometime before starting the activity without

affecting the overall project completion.

Similarly, depending upon the starting time and the

duration, the activity may be completed at different

times.

Earliest start time of an activity: This is the earliest,

that the activity (i, j) can be started, i.e., all the necessary

preconditions are met. Earliest start time of an activity (i,

j) has been denoted by EST(i, j)

Earliest finish time of an activity This is the earliest,

that an the activity (i, j) can be completed. Earliest finish

time of an activity (i, j) has been denoted by EFT(i, j)

Mathematically, the relationship can be expressed as

EFT(i, j) = EST(i, j) + D(i, j)

Latest finish time of an activity: This is the latest

time that an activity needs to be completed in order that

there is no delay in the project completion. Latest finish

time of an activity (i, j) has been denoted by LFT(i, j)

Latest start time of an activity This is the latest time

when an activity must be started, in order that there is

no delay in the project completion. Latest start time of

an activity (i, j) has been denoted byLST(i, j)

Mathematically, the relationship can be expressed as:

LST(i, j) = LFT(i, j) − D(i, j)

FORWARD AND BACKWARD PASS

The forward pass moves from the ‘start’ node towards the ‘finish’ node, and basically calculates the earliest occurrence times of all events.

Considering that the project starts at time zero, the earliest occurrence time at each node is found by going from node to node in the order of increasing node numbers, keeping in mind the logical relationships between the nodes as shown by the connecting arrows.

The earliest occurrence time for any node can be estimated from the (maximum) time taken to reach that node from the different incoming arrows.

he backward pass is made in a similar manner to

that of the forward pass, except that the process is

carried out in reverse through the nodes, starting

from the end node and finishing at the start node.

the late occurrence time for different nodes can be

found out, depending on whether there is a single

outgoing arrow from a node

For the end node the late occurrence time is

considered same as the earliest occurrence time.

The late occurrence times for these nodes can be

simply determined as Li = Lj − D(i, j)

In case if multiple arrows reaching same node,

Li = Mjin[Lj − D(i, j)], where the minimization is over

all nodes j that precede node i.

for some events (nodes) in the network, the two

values (E and L) will be the same if the latest

project completion time is taken as the earliest

project completion time.

These events are called critical events and the path

is called critical path.

FLOAT OR SLACK TIME

The time period by which an activity can be delayed without adversely affecting project completion.

Total float in an activity Total float of an activity is the amount of time by which the start of the activity may be delayed without causing a delay in the completion of the project. This is calculated as

TF(i, j) = LST(i, j) − EST(i, j)

Or

TF(i, j) = LFT(i, j) − EFT(i, j)

The values of TF(i, j) calculated from above equations are referred to as start float and finish float respectively.

In terms of event times, the TF(i, j) can be defined

as the late occurrence time Lj of the succeeding

event minus the early occurrence time Ei of the

preceding event minus the duration of the activity

defined between these events.

Thus,

TF(i, j) = Lj − Ei − D(i, j)

Free float Free float is the amount of time by which

the start of an activity may be delayed without

delaying the start of a following activity.

Free float is defined as the earliest occurrence

time Ej of the following event minus the earliest

occurrence time Ei of the preceding event minus the

duration of the activity defined between these events.

Free float for an activity (i, j) is denoted by FF(i, j) and

is calculated from the following expression: FF(i, j)

= Ej − Ei − D(i, j)

Independent float Independent float is the amount

of time by which the start of an activity may be

delayed without affecting the preceding or the

following activity.

Independent float is defined as the earliest

occurrence time Ej of the following event minus the

latest occurrence time Li of the preceding event

minus the duration of the activity defined between

these events.

Independent float for an activity (i, j) is denoted by

IF(i, j) and is calculated from the following

expression: IF(i, j) = Ej − Li − D(i, j)

Interference float:

It is defined as the difference in total float and free

float.

In other words, Interference Float =

TF(i, j) − FF(i, j)

Critical Path:

The ‘critical path’ is defined as one that gives the

longest time of completion (of the project).