A GA-based heuristic approach for offshore structure construction spatial scheduling under uncertainty

Abstract

Spatial scheduling is the key process that constraints the productivity and time in offshore structure construction. However, block processing times are usually uncertain in reality. To address the uncertain characteristics of block processing times and the effects on construction makespan, a heuristic genetic algorithm approach was proposed. This paper presents a fuzzy triangular model to represent the uncertain processing times. We not only focused on the optimisation of block layouts and construction makespan, but also investigated the effects between the fuzzy makespan and the uncertainty of it. Real data are used in our empirical study to support the model. Sensitive analysis by changing uncertainty spread was conducted and results revealed that the uncertainty of fuzzy makespan imposed a non-linear negative effect on makespan. In real application, practitioners can assign greater weight to processing uncertainty when task is time oriented or less weight when task is just-in-time oriented.

Keywords:

• offshore structure
• construction
• spatial scheduling
• genetic algorithm
• uncertainty

Acknowledgements

This work is partially supported by State Key Laboratory of Ocean Engineering (Shanghai Jiao Tong University) under Project [grant number GKZD010056) and MOE (Ministry of Education in China) Project of Humanities and Social Sciences [grant number 12YJCGJW001].

Additional information

Notes on contributors

Lei Dai

Lei Dai is a PhD student in the Department of Transportation, Shipping & Logistics, Shanghai Jiao Tong University, Shanghai, P.R. China. His research interest is in offshore engineering project management and shipping economy. He has published research papers in Maritime Policy & Management, International Journal of Trade, Transportation and Logistics and Transportation Letters.

Hao Hu

Hao Hu is a professor and chair of the Department of Transportation, Shipping & Logistics, Shanghai Jiao Tong University. His research areas include marine transport, project management and transportation planning and management. His publications have appeared in many international journals.

Feier Chen

Feier Chen is a lecturer in the Department of Transportation, Shipping & Logistics, Shanghai Jiao Tong University. Her research interest includes shipping economy and logistics. She has published several research papers.