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INTEGRATING CONSTRUCTABILITY WITH LEAN CONSTRUCTION & WORK PLAN
[email protected]://www.construction-productivity.co.uk
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
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