MODELLING TO RESOLVE DESIGN LINKED DELAY IN CONSTRUCTION PROJECTS

Abstract

Consultants are the major role players in design of construction projects. It is well acknowledged that the consultant and design linked issues are more or less integrated and influence delay in a project. Therefore, the objectives of the investigation are to identify the influential consultant and design related variables, which cause delay; to evolve the causal feedback relations among the most influential consultant and design linked variables and delay; and to develop a model to estimate the reduction of delay under varied strategic interventions. For this purpose a survey was conducted among 120 stakeholders and professionals from various construction projects in India. By using System Dynamics (SD) modelling principles, causal feedback relations among the most influential parameters that influence delay were established and dynamic hypotheses were evolved for developing policy interventions to reduce delay. A SD model was developed by using data from medium sized building projects in India to examine the behaviour of the project schedule and delay under different simulated scenarios, and estimate the reduction of delay under different policy interventions based on the dynamic hypotheses framed. Findings suggest that there exist definite causal feedback relations among the consultant and design linked variables, such as late reviewing and approving of design documents by consultant, delay in approving major changes in the scope of work by consultant, delay in performing inspection and testing by consultant, poor communication/coordination between consultant and other parties, inflexibility (rigidity) of the consultant, delays in producing design documents, complexity of project design, mistakes and discrepancies in design documents, and unclear and inadequate details in drawings, which essentially cause delay. However, the model results revealed that policy interventions based on (1) causal feedback mechanisms involving appointment of highly competent consultant and design team, delay in producing the design documents and delay in construction; and (2) provision of effective communication mechanism, conflict resolution and delay in construction can reduce delay significantly.