Multimode variable resource-constrained time/cost trade-off problem in repetitive projects with adjustment strategy

Resource availability is the crucial factor of construction project scheduling decision, as it impacts the time and cost of the project. However, traditional researches assume that resource availability is fixed, which does not reflect the actual situation. This article proposes a model for addressing the multimode variable resource-constrained time/cost trade-off problem (Mvrc-DTCTP) in repetitive projects. To better capture the characteristics of repetitive projects, an adjustment strategy is designed to mitigate the impact of work continuity interruptions on idle time. Through simulation analysis, it was found that increasing resource supply can reduce project duration, but it is not directly proportional to cost. This phenomenon further increases the uncertainty in the relationship between duration and cost, inevitably affecting managers' ability to develop effective scheduling plans. By employing the Mvrc-DTCTP model, project managers can obtain more and better solutions than traditional methods, with shorter duration, and lower total cost. The proposed adjustment strategy results in a 54% reduction in idle time, a $4000 cost reduction and more feasible solutions. Based on calculations for 30 randomly generated cases, the adjustment strategy achieves optimization rates ranging from 24.43% to 84.24%. The adjustment strategy demonstrates the best optimization effect when the resource supply level is moderate.