Optimization of uncertain construction time-cost trade off problem using simulated annealing algorithm

The problem of time-cost trade off analysis (TCT) is a well-known standard problem in construction management world and it is one of the most important aspects of construction project planning and control. There are tradeoff between time and cost to complete the activities of a project; in general, the less expensive the resources used, the longer it takes to complete an activity. This problem represents a challenging task because the activity duration and cost have uncertainty associated with them, which should be considered when performing schedule optimization. This paper proposes a hybrid technique that combines simulated annealing algorithms (SA) with fuzzy logic to solve construction project time-cost trade-off problem under uncertainty. Fuzzy set theory is applied to model the managers´ behavior in predicting time and cost pertinent to a specific option within an activity. SA is used as a searching mechanism to establish the optimal time-cost profiles under different risk levels. A simple case study is used for testing the proposed approach. In comparison with the previous models, the new model provides managers with greater flexibility to analyze their decisions in a more realistic manner. The results also indicate that SA is able to generate solutions with high quality make it suitable for solving trade off optimization problems in the construction management field.