Heuristic and exact methods for the large-scale discrete time-cost trade-off problems

Thesis Type: Doctorate

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

Approval Date: 2018


Supervisor: RİFAT SÖNMEZ


Construction industry necessitates formulating impeccable plans by decision makers for securing optimal outcomes. Managers often face the challenge of compromising between diverse and usually conflicting objectives. Particularly, accurate decisions on the time and cost must be made in every construction project since project success is chiefly related to these objectives. This is realized by addressing the time-cost trade-off problem (TCTP) which is an optimization problem and its objective is to identify the set of time-cost alternatives that provide the optimal schedule(s). Due to discreteness of many resources in realistic projects, discrete version of this problem (DTCTP) is of great practical relevance. The Pareto front extension of DTCTP is a multi-objective optimization problem that facilities preference articulation of decision makers by providing them with a set of mutually non-dominated solutions of same quality. Due to the complex nature of DTCTP, the literature on large-scale problems is virtually void; besides, most of the existing methods do not suit actual practices and popular commercial planning software lack tools for solution of DTCTP. The main focus of this thesis relates to providing means for optimization of real-life-scale Pareto oriented DTCTPs and it aims to contribute to both researchers and practitioners by tightening the gap between the literature and the real-world requirements of the projects. The results of the comparative studies reveal that the proposed methods are successful for solving large-scale DTCTPs and provide the management with a quantitative basis for decisions on selection of the proper alternatives for the real-life-scale construction projects.