The Research On Project Time-cost Tradeoff With Complex Precedence Relations

Nowadays,the technical requirements of large-scale engineering projects are getting higher and higher,and the overlap relationship between various processes in the construction process is becoming more and more complex.In the single code overlap network planning with complex overlap relationship,there are also a series of phenomena which are contrary to the traditional network planning theory,making the network planning can not effectively guide the implementation of the project,affecting the implementation efficiency of the project,and increasing the cost of investment.Paradox phenomena include path length paradox of key process,total time difference paradox of non-key process and decomposition paradox.This paper summarizes the problems caused by paradox phenomena,and analyses the causes of paradox phenomena and the refinement of general situation.On the basis of introducing the theory and algorithm of network planning and GPRs lapping network,this paper puts forward an improvement of the lapping relationship description method of GPRs lapping network planning in view of the above paradox,that is,to change the lapping relationship between processes into the lapping relationship between process nodes and form a new type of network planning.In the new network plan,it can effectively explain and avoid the paradox in the traditional single code network plan.With the continuous improvement of the drawing method and algorithm of network plan,the calculation method described in this paper will further promote the development of project management and improve the level of project management.On the basis of improving the GPRs lapping network plan,the time-cost trade-off optimization of the new lapping network plan is carried out.Firstly,the cost composition of the project is analyzed,and the project planning cost is divided into direct cost and indirect cost.Secondly,it clarifies the relationship between the time and cost of the project,that is,the direct cost is determined by the duration of each process,while the indirect cost is determined by the duration of the project.Finally,the time-cost optimization of the project is carried out by using the characteristics of paradox,which includes two aspects: reverse process method to reduce the direct cost and decomposition process method to reduce the direct cost.In addition,this paper also takes the highway construction project as an example to improve the lapping relation drawing method of GPRs lapping network plan,and optimizes the time-cost of the project.