THE IMPACT OF OVERHEADS VARIATION ON TIME-COST OPTIMISATION OF BUILDING INFRASTRUCTURE PROJECTS

Abstract

The research aims at investigating the impact of indirect expenses (overheads) variation on time-cost optimisation (TCO) of building infrastructure projects. The study’s main objectives are to propose a practical methodology for time-cost planning of buildings and to analyse the relationship between level of overheads and minimum project duration with respect to contractor’s profitability. The methodology entails the development of a TCO linear programming (LP) model founded on PERT/CPM network analysis, and its subsequent implementation to an actual public building project - a three-storey nursery school for a municipality - for the assessment of minimum project duration for a given gross profit when altering the fixed amount of overheads. The LP mathematical model is solved with Solver optimisation add-in for Microsoft Excel©. Useful prototype minimum project duration vs. project overheads trade-off curves are derived to support project management decisions. The proposed TCO approach may serve as a valuable scheduling tool, providing stakeholders important insight into the relationship between level of project overheads, profit and duration. The study is expected to assist both construction researchers and practitioners towards more effective decision-making in the planning process of building projects.