INTEGRATING CONSTRUCTABILITY WITH LEAN CONSTRUCTION & WORK PLAN

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Constructability is the integration of construction expertise into all phases of the project.

For Improving factors such as:cost schedule quality overall project objectives

Constructability must be used at key points in the project life cycle. This includes:

in the planning phase;early in the design phase; prior to the procurement phase;prior to the mobilization phase for construction.

Constructability process considers a detailed review of:

Design drawings; Models; Specifications; construction processes.

This is carried out by one or more highly experienced construction Engineers or specialists.

working closely with the project team including cost engineering;

this is carried out prior to construction mobilization;

before construction work is put for tender.

• The purpose of the constructability review is to identify the following items:

• Design errors (both material selection or dimensions).

• Un clear specifications.

• Project features-difficult and very costly to construct.

• Project complexity- that exceed the knowledge and capability of industry to properly build.

• Project features that are difficult to interpret and will be hard to accurately bid.

IMPLEMENTINGPROJECT

CONSTRUCTABILITY

CostSchedule Quality

Overallobjectives

knowledge gained fromother projects

Considers adetailed review

of:Design

drawings,Models,

Specifications,Construction

processes/siteoperations

procurement

HighlyexperiencedSpecialiststeam

Labourefficiency

Fewerdelays/

disruptionsLean

construction

Shortenedduration ofactivities

etc

Defectsfree

productetc

Supply ChainManagementJust-In-Timetechniques

ISO 9000etc

Constructability

Remove

Riskcontrol Conflict

Longdurationsactivities

DisruptionsDelays

Finderrors

etc.

Strategy

Schedulelogic

Mistakes inconstruction

sequence

Projectcomplexity

Projectfutures

Dimensions

Marital

Standardize

Activitieshard

tocontrol

Information(MIS )

Communication at all levels

Strategy

Schedulelogic

PlanningDesign-prefabrication

procurementSite operation

Lean construction main objective is to maximize value and reduce waste.

It applies specific techniques in an innovative project delivery approach.

including:1. supply chain management, 2. Just-In-Time techniques.

Just-In-Time(JIT)

Supply ChainManagement

(SCM)

LeanConstruction

maximizes valuereduceswaste

Based on LeanManufacturing, of the Toyota

Production system

High productivity

LAST PLANNERSYSTEM

As well as the open sharing of information between all the parties involved in the production process.

Lean manufacturing is an outgrowth of the Toyota Production system.

Developed by Taichii Ohno in Toyota in the 1950s.

It is based on lean manufacturing, of the Toyota Production system. Ohno learnt from mass production at Ford Motor manufacturing facilities in the U.S. and witnessed high level of waste during production.

Ohno identified several wastes in mass production systems in car industry such as:

1. overproducing2. waiting time 3. transporting

also, in other areas such as:1. processing methods; 2. unnecessary stock on hand; 3. unnecessary motion;4. defective goods; 5. failure to meet customers’ needs;6. high waste through out the

process. He would be very disappointed by recent failures in Toyota car performance.

Womack and Jones (1996) suggested that there are five key principles that need to be monitored when lean construction systems are applied in construction. Those are:

Value-clarifying the customer’s needs; the supply chain involvement in all

stages, from inception to completion; By clarifying activities or products that signify value.

Value stream: By mapping thewhole value streamestablishing cooperation between all parties involved;

identifying and eliminating waste;

From taking such steps the construction process can be improved.

Flow: Business flow includes project

information such as:1. specifications 2. contracts 3. plans, etc. Job site flow involves the

activities and the way they have to be carried out.

Supply flow refers to the materials used in a project.

Pull: The efforts of all participants provides smooth pulls during the construction process.

Perfection: Use of best methods of work instructions and best procedures.

Introduction of best quality control methods.

Just-In-Time(JIT)

Supply ChainManagement

(SCM)

Business FlowPull

Perfection

LeanConstruction

maximizes valuereduceswaste

Based on LeanManufacturing, of the Toyota

Production system

JIT onlyconsiders the

Resourcesrequired

Construction LeanImprovement Programme

(CLIP),(Supply chain)

High quality product with minimallead-time

Eliminating delays and disruptions

This well planned and systematic approach helps the management team to create quality work plans.

They learn from any failurea good WorkPlan is a weekly work plan

based on lean constructionproduction scheduling

screening work package constraint percentage of planned completed (PPC)

Scheduling of construction work is often done with the help of computer tools

It implement the critical-path method (CPM)

based on activities of given duration and unit resources allocated to them

as well as predecessor relationships between activities

for different parties involved in a construction project to communicate with one another whom should be doing what work and when.

The application of lean production techniques in construction has been triggered by its success in manufacturing (Womack and Jones 1996).

Weekly work plans can be developed as valuable tools for production planning and control.

This is possible through the application of lean construction techniques.

In the application weekly work plans are generated using a database (Choo, Tommelein

Activity Description Predecessors

A Site clearing ---

B Removal of trees ---

C General excavation A

D Grading general area A

E Excavation for utilitytrenches B,C

F Placing formwork andreinforcement for concrete B,C

G Installing sewer lines D,E

H Installing other utilities D,E

Pouring concrete F,G

Activity-on-Arrows Representation of a Nine Activity Project

Defining Precedence Relationships Among Activities

1 3 82 11 15

12

0

0

14

14

40

40

4

55

43

43

47

47

55

55

61

61DU=14 DU= DU= DU= DU=54

44

58

9

44

47

7

55

59

14

45

45

6

55

55

13

70

70

17

43

46

5

45

59

10

59

66

16

26

DU=4

DU=1

DU=1

3

DU=2

DU=1

DU=1

DU=1 8

DU=1

DU=4

DU=3

DU=2

DU=2

IMPLEMENTINGPROJECT

CONSTRUCTABILITY

planningphase

Designphase

Procurementphase

prior to themobilization phase

for construction

ConstructionphaseKPIs

Completionphase

Handover

inceptionphase

LeanConstruction

Just-In-Time(JIT)

Supply ChainManagement

(SCM)

maximizes valuereduces waste

LAST PLANNERSYSTEM

ConstructionPlan

Resourcesand cost

ResourceOrientated

Criticalpath

NetworkAnalysis

TimeOriented

Scheduleof

workbased plan

IndirectCost

involved

DirectCost

involved

Budgetbasedplan

High Productivity