Study On The Method Of Determining Project Quality Guarantee Under The Consideration Of Contractor Credit Level

Engineering quality is one of the basic objectives of construction projects.Under the condition of market economy,as the contractor and responsibility subject of construction project implementation,the quality assurance system based on its credit level plays a basic decisive role in the project quality.As a guarantee method of project quality and a contract restriction means to promote the contractor to improve the credit level of quality assurance,quality deposit has been widely used in the field of project contracting for a long time.In engineering practice,the amount of quality deposit is generally determined according to relevant regulations or referring to engineering experience or market practice.Sometimes,the Contractor’s credit level is high,but the quality deposit is also high,resulting in the loss of the Contractor’s capital efficiency.In the long run,it will also cause the general rise of the contract price.Sometimes,the Contractor’s credit is poor,but at the same time,the amount of quality deposit is insufficient,which will significantly increase the cost of business The quality risk and quality control burden of the owner.At present,the research on how to determine the amount of deposit is not enough.Based on the analysis of the relationship between the Contractor’s credit level,project quality assurance,the owner’s monitoring level and the quality deposit,this paper takes the owner who bears the primary responsibility for project quality as the guide.The main contents of this paper are as follows:(1)The concept,characteristics and function of quality guarantee are expounded.The factors affecting the retention of quality security are studied(2)Under the condition of symmetric information,combined with the characteristics of water conservancy project construction,taking the credit level as the decision variable of the contractor,the project quality supervision level and quality deposit retention as the decision variable of the owner,the quality expected benefit model of the owner and the contractor is constructed.When the owner’s quality supervision cost and the Contractor’s credit cost are linear function,quadratic function and non concave non convex function Based on the maximum principle,the optimal solution of the owner’s quality supervision decision and the detaining strategy of the quality deposit are derived respectively,and the decision results under symmetric information are analyzed through simulation calculation.(3)Under the condition of asymmetric information,based on the quality expected benefit model of the owner and the contractor,when the owner’s quality supervision cost and the Contractor’s reputation cost are linear function,quadratic function and non concave and non convex function,the optimal solution of the owner’s quality supervision decision and the detaining strategy of the quality deposit are deduced respectively by using the control theory;through the simulation calculation,the decision under asymmetric information is analyzed result.(4)Under the condition of incomplete information,based on the quality expected benefit model of owner and contractor under symmetric information,the quality expected benefit model of owner and contractor under incomplete information is constructed by introducing symmetric coefficient.When the owner’s quality supervision cost and contractor’s reputation cost are linear function,quadratic function and non concave and non convex function,the owner’s quality expected benefit model is deduced by maximum principle and control theory respectively The optimal solution of quality supervision decision and quality deposit detaining strategy is obtained,and the decision result under incomplete information is analyzed by simulation.