ASSESING OUR DESIGN CAPACITYIS OUR DESIGN CHANGE FREE ?

B Y M U H A M M A D D A N I YA L

Design Capacity

State of design completion in construction industry.1

2

3 Major causes of delays in construction projects

Factors and Owners which causes changes in design during construction stage

Objectives are to assess

MethodologySurvey Design

Survey Administration

Data Validation

Descriptive Statistical Analysis

Relative Responsive Index Analysis

Findings and Observation

Conclusion

Survey Design

Name, OrganizationExperience, RoleIdentificati

on

State of Design

Project BriefAdoption of StandardsDesign usability at Tender and Construction stageMajor causes of changesOwner of changesResponsibility of Stakeholders in approval process

Changes

Major causes of delaysDelays

Survey Design

Survey Administration

Total questionnaire sent

Total questionnaire receivedInvalid questionnaire

Sample Dynamics

35

31

1

3%

57%13%

27%

Client Project ManagersDesign Consultants Contractors

Response percentage

86

Survey Analysis

State of Design

Changes

Delays

Descriptive StatisticsMean, Median, Mode, Standard Deviation

𝑅𝐼𝐼=∑𝑊𝐴∗𝑁 (0≤𝑅𝐼𝐼≤1)

Relative Importance Index

W : Weight (1 to 5) , A : Highest Weight (5), N : Number of responses (30)(Muhwezi et al, 2014)

Findings and Observations

• Construction projects are frequently based on client’s project brief (M=3.8, S.D=1.10)

• Project brief is provided occasionally in written and concise manner (M=3.2, S.D=1.10)

• Project brief is frequently changed by the client in middle of the design phase (M=3.70, S.D=0.75)

• Consultants occasionally adopts standard form of specification and cost codes like CSI Master Format, NRM 2, SMM 7 etc. (M=3.00,S.D=0.75)

• Consultants occasionally draft tailor made specification in tune to the project (M=3.03, S.D=1.13)

State of design completion in construction industry.

1

Findings and Observations

• Industry is in agreement that construction planning could be done based on information available at the tender stage (M=3.57, S.D=0.94) .

• but they are of neutral opinion regarding the exact quantities (M=3.43, S.D=0.97), cost (M=3.37, S.D=0.93) and arrangement of tools and plants for works (M=3.40, S.D=0.97).

• They significantly dis-agree with the statement that ordering of materials (M=2.93, S.D=0.93) and execution of works (M=2.13, S.D=1.12) could be done with the information available at tender stage

State of design completion in construction industry.

1

Findings and Observations

• This confidence level do not increase considerably when the design is transferred to construction stage where the industry agree but not strongly with the statement that construction planning (M=4.30, S.D=0.56), quantification (M=4.07, S.D=1.07), costing (M=4.13, S.D=0.95), arrangement of tools and plants (M=4.23, S.D=0.87), ordering of material (M=4.17, S.D=0.70) and execution of works (M=4.27, S.D=0.69) could be done with the information available at construction stage.

State of design completion in construction industry.

1

Findings and Observations

• Enhancement of design details is the number 1 factor (RII=0.747) constituting towards change in design after its issuance for construction.

• Followed by coordination issues among services No. 2 (RII=0.733), cost curtailment No. 3 (RII=0.733) and changes in design brief No. 4 (RII=0.713).

• It is to be noted that site related issues like design development in shop drawings, constructability issues and changes in selection of materials ranked 4, 5 and 6 with RIIs of 0.647, 0.640 and 0.600 respectively which is below 0.700 mark.

Factors and Owners which causes changes in design during construction stage

2

Findings and Observations

• Design Consultant and Client are rated no. 1 and 2 in terms of introduction of changes (RII=0.827 and 0.813 respectively) while the RIIs of Project Managers (RII=0.513) and Contractor (RII=0.433) were below 0.599 making them insignificant.

• For importance of stakeholders in approval process of changes and variation order client was ranked at no. 1 and design consultants were ranked at no. 2 with RIIs of 0.880 and 0.780 respectively.

Factors and Owners which causes changes in design during construction stage

2

Findings and Observations

• Missing information in construction documents as the number 1 cause of delay (RII=0.820).

• Followed by delay in resolution of queries ranked at no.2 (RII=0.760)

• Introduction of frequent design changes ranked at no.3 (RII=0.733)

• The occurrence of delays due to sampling and approval process are ranked between 4 and 6 with RIIs ranging between 0.687 and 0.620.

• Unavailability of material and labor as well as billing and cost related issues are all ranked below no.6 with RIIs of less than 0.599 making them insignificant.

Major causes of delays in construction projects3

Conclusion• Design is dependent on project brief which is occasionally

provided and frequently changed by the client.

• Standards not adopted and specification not tailored for individual projects the confidence of contractor on the construction document remains below the optimum level,

• It is further reduced by introducing frequent changes to complete the incomplete and further enhance the level of design at construction stage.

• This factor also constitute mainly towards the delay that occurs on the project.

Conclusion

• The hypothesis thus presented paints a dark picture of design capacity in our industry.

• Despite of having professionals of repute and experience we are facing the dilemma of changes and re-work which have its financial as well as environmental impacts.

Recommendations

• Client should be well aware of its needs and future plans.

• A clear and concise brief should be provided to the design consultants by the client.

• All stake holders should agree upon that brief and provide surety that a solution can be met by utilizing their skills and abilities.

• Standards for design documentation should be adopted, specification should be tailored specifically for the project well suited to its environment and conditions.

• Construction documents like drawings, BOQs and Specifications etc. should be well coordinated and should communicate a single actual picture of the project.

Recommendations

• Efforts should be made to utilize latest in BIM technology to cater the constructability and service coordination issues that could arrive at site.

• Input of market leading contractors should be taken during the design stage to have a better idea of the real world constraints that could arise during construction.

• Changes should be logged, tracked and managed through a proper system.

(End of Presentation)