| With the the promotion of national policies such as One Belt And One Road and the establishment of Asian Infrastructure Investment Bank,the number of large-scale constructions keeps increasing.The complexity arising from planning large-scale construction projects often requires representation and evaluation of alternative programs.In order to deal with the problems brought by large-scale constructions,more flexible and adaptable schedule approaches are necessary to help describe the alternative programs led by alternative construction methods.However,prevailing schedule tools seldom consider and explicitly represent the alternative activities and relationships for further evaluation.Moreover,how to deal with the temporal relationships associated with alternative activities are also inadequately explored.A large-scale construction project is consisted of many subsections,and there are multiple sequences in each subsection.Considering the possibilities of different sequences,it is hard for classical scheduling approaches to describe all sequences in one model.Therefore,there is risk of missing optimal solution for construction enterprises.In this research,a Mixed Integer Linear Programming model is developed to represent the alternative construction programs,and then the concept of criticality of activities is extended to incorporate the alternative relationships.At the beginning,a representation scheme is rasied,which coverts complex relationships into the combination of simple relationships as well as logical connective.Then XOR and XNOR are introduced to represent the alternative and coexisting relationships between/among activities and temporal relationships.After that,all temporal relationships and logic relationships are converted into linear constraints through the big-M.The computation e xample and the case study demonstrate that project period and the optimal sequence of activities can be derived using the developed model. |
