Linear Optimization Model to Minimize Total Cost of Repetitive Construction Projects and Identify Order of Units

Abstract

This study developed a linear optimization model for scheduling repetitive construction projects with varying quantities of work in repetitive units. The model provides new capabilities that enable planners to identify an optimal/near-optimal schedule that minimizes project total cost and number of times crew work is interrupted. It is capable of identifying the optimal/near-optimal order of executing repetitive units to achieve further reduction in project time and cost. The model was developed in three main phases: (1) identifying input data such as quantities and crew productivity rates; (2) optimizing the construction schedule of repetitive units by identifying decision variables, formulating objective functions, and constraints, and executing model computations; and (3) visualizing the generated optimal/near-optimal schedule, crew interruption, project duration and cost, and order of executing repetitive units. Two case studies of 105 and 6 repetitive units were analyzed to evaluate the model performance. The model resulted in 0.13% and 4.2% additional reduction in project total cost and indirect cost, respectively, for the optimal order of repetitive units compared with the best model in the literature.