Resource-Constrained Project Scheduling And Its Application In Designing Construction Supply Chain

Construction supply chain management is a new area of construction project management and supply chain management. There is still no research on design of construction supply chain. In a construction supply chain where contractor is the kernel, design and operation of the chain is driven by project activity network where capacity of the partners such as specialized subcontractors, ready-mix concrete suppliers, raw material suppliers, will become a constraint to project scheduling. Therefore, resource-constraints from these partners and limitation on project duedate must be considered in design of construction supply chain so that the objective of minimizing activities'cost in project can be achieved. For the above, resource-constrained project scheduling with the objective of minimizing activities'cost will be discussed firstly based on which research on design of construction supply chain is going to be carried out. There is little attention paid to activities'cost of project in resource-constrained project scheduling problems(RCPSPs). When the objective of minimizing activities'cost is considered as the performance measure, the problem is also NP-hard and the objective is nonregular. A mathematical model is put forward for the cases the activities are executed in one execution mode and renewable resources are consumed. The basic thinking is analyzed for solution of the problems in heuristics and three approaches are developed: 1).Scheduling based on Preposing Acitivity Matrix where some rules are developed to form the matrix. 2).Priority-rule-based Scheduling that is updated to achieve the new objective on the basis of the old one for the RCPSPs with makespan objective and some priority rules are employed in the serial schema and the parallel schema. 3).Improved Genetic Algorithm where the schema of encoding is an activities'chain with precedence relationship and the decoding procedure is a serial scheduling schema. Computational Study with the single-mode instances in updated PSPLIB shows that the efficiency of the genetic algorithm proposed is the best and the results will become better when deterministic multi-pass approaches are used. The above research is extended to the cases activities have multiple possible execution modes in the following. In the new problems, the execution modes must be selected for the activities when they are scheduled. A general parallel schedule generation schema is proposed for multi-mode scheduling and two heuristic procedures are developed: united scheduling and two-step scheduling. Computational study with the multi-mode instances in updated PSPLIB shows that, when the factors about the compromised transitively relative cost is considered for selecting execution modes, a relatively fewer valid schedules will be got than the heuristics considering other factors in the same approach, but the average error is the minimal. Additionally, the average error of the heuristics with two-step scheduling is less than that of the heuristics with united scheduling. The renewable resources suppliers are the most immediate partners for contractor in construction supply chain and their capacities will form the constraints to project scheduling. That's to say, when selecting these partners, the RCPSPs must be taken into account. The mathematical model for selecting these suppliers in construction project is proposed and the principle to reduce the solution space is discussed. Following that, a schema with GA to solve the problems is designed that is test by an example. The results show that a fine efficiency can be got with the improved GA. Whereafter, a problem about design of supply-execution construction supply chain is proposed, where one of candidate contractors should be selected to execute the construction project, and the representation of the problems and the approach for solution are all given. Suppliers selection is to solve the problems of designing supply chain in a local facet, but design of supply chain network is in the whole. Based on the analysis about the structure of construction supply chain network, integrated project scheduling and material ordering problems with limited capacities are proposed firstly where bilevel capacities about renewable resources and raw materials are all described. This type of problems can be decomposed to two types of problems: single-mode RCPSP with the objective of minimizing activities'cost(SMRCPSP-AC) and material ordering problem in a finite planning horizon with limited supply capacity(MOP-LSC), where the latter can be solved by dynamic programming. A feasible solution for the integrated problem may be got by searching a feasible solution for SMRCPSP-AC and then solving the relative MOP-LSC, and the optimal one will be found out in the set of feasible solutions for the integrated problem. A schema with improved GA is developed to solve the integrated problems. The numerical computation shows that the efficiency is fine when selection scheme is represented by stochastic tournament model with elitist preservation. This type of problems can be extended to design construction supply chain networks. To solve the proposedproblems with GA, the schema of encoding is an integrated one including two segments where suppliers and activities are encoded by different schemas and the decoding procedures are processed separately after which, SMRCPSP-AC and MOP-LSC are formed and solved in turn to get a feasible solution of designing construction supply chain network. Different operators are used on the two segments in the chromosome. It can be concluded based on the computational study that this type of problems can be solved by using the above genetic algorithm.