A mixed integer programming method for integrated discrete time-cost trade-off and manpower resource leveling problem

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2016


Supervisor: RİFAT SÖNMEZ


Construction projects have to meet all of the objectives of scope, quality, schedule, budget simultaneously. These objectives, however, cannot be considered as independent of each other. For example, an increase in direct resources will usually lead to shorter activity durations. A shorter project duration results in lower indirect costs, whereas the additional resources cause an increase the project’s direct costs, in general. This phenomenon is defined as time-cost trade-off problem (TCTP). Nevertheless, in some cases supplying extra resources may increase the indirect costs, too. Hence, the need for a comprehensive approach, integrating TCTP with the optimal manpower resource utilization values, is crucial for optimizing the resources along with the cost. In the literature, however, this problem is considered as two independent sub-problems as TCTP, and resource leveling problem (RLP). This study introduces an integrated approach considering TCTP and RLP, simultaneously. In this context, a mixed integer programming (MIP) model is presented for solving the discrete time-cost trade-off problem (DTCTP) and resource leveling problem simultaneously. Since there are no benchmark problems for the proposed problem, 1215 benchmark instances are generated for the integrated discrete time-cost trade-off and resource leveling problem (DTCTRLP). A great majority of (97.28%) 10-activity problems are solved, successfully; nonetheless, the solution rate decreased as the problem’s activity and mode numbers increase. In addition, the proposed procedure is compared with the current approach in the literature (i.e. consecutive implementation of TCT and RLP), to illustrate the contributions of the proposed approach.