Ezeldin, A S and Soliman, A (2009) Hybrid time-cost optimization of nonserial repetitive construction projects. Journal of Construction Engineering and Management, 135(1), pp. 42-55. ISSN 0733-9364
Abstract
Time-cost trade-off analysis represents a challenging task because the activity duration and cost have uncertainty associated with them, which should be considered when performing schedule optimization. This study proposes a hybrid technique that combines genetic algorithms (GAs) with dynamic programming to solve construction projects time-cost trade-off problems under uncertainty. The technique is formulated to apply to project schedules with repetitive nonserial subprojects that are common in the construction industry such as multiunit housing projects and retail network development projects. A generalized mathematical model is derived to account for factors affecting cost and duration relationships at both the activity and project levels. First, a genetic algorithm is utilized to find optimum and near optimum solutions from the complicated hyperplane formed by the coding system. Then, a dynamic programming procedure is utilized to search the vicinity of each of the near optima found by the GA, and converges on the global optima. The entire optimization process is conducted using a custom developed computer code. The validation and implementation of the proposed techniques is done over three axes. Mathematical correctness is validated through function optimization of test functions with known optima. Applicability to scheduling problems is validated through optimization of a 14 activity miniproject found in the literature for results comparison. Finally implementation to a case study is done over a gas station development program to produce optimum schedules and corresponding trade-off curves. Results show that genetic algorithms can be integrated with dynamic programming techniques to provide an effective means of solving for optimal project schedules in an enhanced realistic approach.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | construction management; hybrid methods; optimization; uncertainty principles |
| Index terms: | case study, dynamic programming, time-cost trade-off, implementation, construction industry, duration, mathematical model, genetic algorithm, scheduling, cost optimization, housing project, repetitive construction, validation, construction project, program |
| Subjects: | contractual arrangements, operations research, data collection methods, mathematical modelling, industry analysis, project controls, housing and residential development, building construction, production management, professional development, quantity surveying, economics, algorithms, software systems |
| Topics: | Procurement, Construction Technology, Risk Management, Information Management, Project Management, Research Practice, Cost Management, Time Control, Urban Studies, Digital Applications |
| Descriptive scope: | 5 PCTEA |
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