Multi-mode Time-Cost Trade-off In Construction Project Under Fuzzy Resources

It's unreasonable to pursue a single objective in construction project management. After reviewing previous research on time-cost tradeoff under different conditions, we find that researchers don't pay enough attention to uncertainty in resources; they neither describe uncertainty in resources in detail, nor point out the effect of uncertainty to time and cost.Therefore we lay emphasis on description of uncertainty in resources in construction projects. We categorize resources in projects into 3 kinds: Machinery, labor and material. Uncertainty of machinery lies in available time as machinery needs to be maintained periodically, while uncertainty in labor and material lies in uncertain available amount because of delay in supply or storage volume. Available time of machinery is expressed by trapezoidal fuzzy number and available amount of labor and material are expressed by triangular ones. Linguistic variables are introduced to describe activity duration and resource amount. Duration of activity can be seen as a function of resource amount, so we established a non-linear relation between them based on if-then rule. We establish a time-cost tradeoff model under fuzzy available time of machinery, fuzzy available amount of labor and material. We introduced a case and solve the model using immune genetic particle swarm optimization algorithm. Results verify the validity of proposed model.