PROJECT PLANNING : TECHNIQUES FOR TIME & COST ESTIMATION FOR CONSTRUCTION PROJECTS

presented by

Dato’ Ir. Dr. Ahmad Anuar Othman

PEng, FIEM, ACPE, MMSET, MIQM, MRCA, MPMI, CCPM, PMP
DIRECTOR

FLOOD MANAGEMENT SECTION

Presentation Outline

1. Introduction
2. Project Management Process
3. Triple Constraints
4. Time Estimation
5. Cost Estimation

6. Conclusion

2

INTRODUCTION

What is a Project?

The PMBOK Definition

TEMPORARY A Temporary Endeavour undertaken
UNIQUE to Create a

Unique Product, Service or Result.

Definition of Project

TEMPORARY UNIQUE OUTCOME

DEFINITE specific purpose, for different stakeholders, done at
different location, use different design or configuration,
Beginning & End done under different circumstances/situations,
encounter different constraints, facing different risks.

UNIQUE

Project – in Brief

Projects are temporary in
nature, have definite start
and end dates; produce a
unique product, service, or
result; and are completed
when their goals and
objectives have been met
and signed off by the
stakeholders or when the
project is terminated.

Operations

Are ongoing and repetitive.

Involve work that is continuous without an
ending date, and you often repeat the

same processes and produce the same
results.

The purpose of operations is to keep the
organization functioning, whereas the

purpose of a project is to meet its goals
and to conclude.

What is
Project Management?

Project Management

PMBOK 01 TOOLS

The application of tools, 02 TECHNIQUES
techniques, skills and 03 SKILLS

knowledge to project activities
to meet the project
requirements.

04 KNOWLEDGE

Project Management Process

I1 I Initiating
P P Planning
E Executing
C 6 2
5 M&C Monitoring & Controlling
7 E
3 C Closing

M&C 4 E

I

Project Management Process Group

INITIATING
Beginning of each phase.
PLANNING
Process of formulating and revising project
goals and objectives and creating the project
management plan.
EXECUTING
Putting the project management plan into action
and utilize most project time and resources.
MONITORING & CONTROLLING
Performance measurement are taken.
CLOSING
Brings a formal, orderly end to the activities of a
project phase or project itself.

RAJAH JPSPK2020 : PROSES-PROSES UTAMA DALAM
PENGURUSAN PROJEK



TIME ESTIMATION

Tools and Techniques for Estimate

Expert Judgment
▪expert judgment guided by historical information, provides valuable insight from prior
similar project.
Analogous Estimating
▪uses values from previous similar project as the basis for estimating the same parameter or
measurement for a current project.
Parametric Estimating
▪uses a statistical relationship between relevant historical data and other variable (e.g.
square meter in construction)
Three Point Estimating
▪uses most likely (M), optimistic (O) and pessimistic (P). Estimate = (O+4M+P)/6
Bottom-up Estimating
▪is a method of estimating a component of work individually and then rolls them up to derive
a total project cost estimate.

Expert Judgment - Water Transfer Project

To Penang Sungai Perak

canal Intake
Structures

Work Break Down Structure

The WBS is foundation of a project.

Forming a basis for project planning and
execution.

Project costs and time are estimated at
the work package or activity level.

WBS

Work package
or activity

Example: WBS FOR ROAD PROJECT

PROJEK PEMBINAAN JALAN

PRELIMINARY ROAD WORK FINAL INSPECTION

Performance CH 00 - 50 CH 50 - 100
Bond

Insurance Earthwork Geotechnical Drainage Pavement Road Electrical Earthwork Geotechnical
Works Works Furniture Works Works

Site office Stripping of Laying of Excavation Preparation of Install Traffic Underground Stripping of
Topsoil Geotecxtile Formation and Barrier Ducts and Topsoil
Survey & Supply and Proof Rolling Cable
Setting Out Excavation Soil Install Pipe Road Line Excavation
USM Replacement Subbase and Road Lighting USM
Site Clearance Culvert 250mm Marking Column and
& Earthworks Feeder Pillar Common
Supply and Works Excavation
Environmental Install V
Management Common Roadbase Concrete Embankment
Excavation shape Drain 300mm Kerb Fill
Plan (EMP)
Embankment Prime Coat Turfing and
Traffic Fill Hydroseeding
Management Binder
System (TMS) Course Fencing and
Gating

Turfing and
Hydroseeding

Tack Coat

Wearing
Course



Estimate Activity Duration

Estimate how much time each Padding is a sign of poor
activity will take. Need to refer project management.
to historical data and lesson
learned about activity duration.

Project manager should use
reliable and realistic approach
in estimating and not simply
guessing or padding.

How Is Estimating Done?

Analogous Estimating (Top down)

It is a gross value estimating It is less time consuming and less
technique. costly than other estimating
technique, but it is also less
accurate.

Analogous estimating can be Example : The last five projects
used to determine overall similar to this one each took
project duration and cost eight months, so this one should
estimate for the entire project. also take same duration.

How Is Estimating Done?

Parametric Estimating

Quantitatively Can be highly Example :
based estimating accurate if the time per
that multiplies the data you are linear meter,
quantity of work by using is reliable. time per
the rate. installation.

How Is Estimating Done?

Three Point estimating

(PERT analysis, Program Evaluation and Review Technique)

There is very small probability of completing a project on
exactly any one date.
It is often best to make estimate in range using three-point
estimate.
Based on three figures – most likely (M), optimistic estimate
(O) and pessimistic estimate (P).

Three Point Estimating - Example

Data from construction of 10 medium traffic bridges
Bridge 1= 43 days Bridge 6 = 55 days
Bridge 2= 50 days Bridge 7 = 48 days
Bridge 3= 60 days Bridge 8 = 50 days
Bridge 4= 65 days Bridge 9 = 62 days
Bridge 5= 50 days Bridge 10= 40 days

Most likely (M) =50 days, Optimistic estimate (O) = 40 days
Pessimistic estimate (P) = 65 days.

Expected Duration= 65 + 4 (50) + 40 = 50.83 Std Dev= 65 - 40 = 4.17
66

There is 68.26 % chance that the project will be completed in 46.66 to 55 days.

Three Point Estimating - Example

Most likely (M) =18 days, Optimistic estimate (O) = 14 days and pessimistic

estimate (P) = 26 days.

Expected Duration = 26 + 4 (18)+14 = 18.67 days + and – (Std dev) to get range of
6 duration

Standard Deviation = 26 - 14 = 2 days, Variance = 4

6

There is 68.26 percent chance that the activity will be completed in 16.67 days

to 20.67 days.

The Normal Distribution

The Normal Distribution



Using Bromilow Time Cost Model

1 Projek Tebatan Banjir dan 3
Projek Sungai, T=217C 0.505
Saliran Bandar, T= 281C 0.335

2 4
Projek Pantai, T=292C 0.314 Projek Pengairan, T=315C 0.545

di mana T = Tempoh pembinaan dalam hari
C = Nilai anggaran kos projek (RM juta)

Bromilow Model in JKR Projects

Kerja Bangunan, T = 327C 0.25
Kerja Kejuruteraan Awam, T = 223C 0.33

Using Bromilow Time Cost Model

Projek Tebatan Banjir dan Saliran Bandar, T = 281C 0.335

If the estimated project cost is RM 50 million, what is expected duration
Expected duration T = 281(50) 0.335

T = 1042 days (35 bulan)

KERJA
KEJURUTERAAN/
TEBATAN BANJIR

KERJA
KEJURUTERAAN

PANTAI

KERJA
KEJURUTERAAN

SUNGAI

KERJA
KEJURUTERAAN

PENGAIRAN

Kaedah Power-Series Estimation untuk
Projek Berkaitan Mekanikal dan Elektrikal

Three quarter rule for cost
0.75

= ⅇ ⅇ

di mana :- Tempoh pembinaan
T= Kos
C= Kapasiti
S= Sedia ada (existing)
e= Rancang (plan)
p=

Square root rule for duration
0.5

= ⅇ ⅇ

Contoh Pengiraan Menggunakan Power-Series Estimation

Three quarter rule for cost

.
= ⅇ ⅇ

Square root rule for duration

.
= ⅇ ⅇ

Di mana:
C= cost, T= duration, p =plan, e = existing

Sebuah Rumah Pam berkapasiti 200 cusec telah dibina dengan kos RM 2.3 juta dalam tempoh 18 bulan.
Apakah anggaran kos dan tempoh untuk pembinaan Rumah Pam berkapasiti 280 cusec.

Three quarter rule for cost Square root rule for duration
Anggaran Kos, Anggaran Tempoh,

. .
= ⅇ ⅇ = ⅇ ⅇ

= 2.3 (280/200) 0.75 = 18 (2.96/2.3) 0.5

= RM 2.96 juta = 24.42 bulan

Di mana:
C= cost, T= duration, p =plan, e = existing

COST ESTIMATION

Estimate Costs

Process of developing an approximation of the cost of resources needed to
complete project work;

This includes human, material and equipment and also other known factors that
can be figured in.

Weighing alternative options and examining risks and trade-offs ( make versus
buy, buy versus lease).

The key of determining accurate cost estimate is work breakdown structure.





Tools and Techniques for Estimate

Expert Judgment Analogous Estimating

guided by historical information, provides uses values from previous similar project as
valuable insight from prior similar project the basis for estimating the same parameter
or measurement for a current project
Parametric Estimating
Three Point Estimating
uses a statistical relationship between
relevant historical data and other variable uses most likely (M), optimistic (O) and
(e.g. square meter in construction) pessimistic cost (P). Estimate = (O+4M+P)/6

Bottom-up Estimating

is a method of estimating a component of
work individually and then rolls them up
to derive a total project cost estimate

Estimating Techniques

Stage Accuracy of Estimation Method
Estimate
Initiation Expert Judgement
-25 % to +75 % (Rough Analogous Estimating
End of Planning order of magnitude) Bottom-up Estimating

-5 % to +10 % A+B+C

A B C Parametric

Estimating

on BQ

• Schedule

of rate
• Expert

Judgement

Bottom up WBS
estimate

Parametric
Cost= Quantity x Rate

Conclusion

Two key features of a project are on-time and
on-budget delivery;

Accurate estimate on schedule and cost help to
fulfill these objectives; and

Project Manager should use reliable and
realistic approach in estimating and not simply
guessing or padding.