According to the present situaton of active service system and reliability optimum allocaton principle, the optimal benefit decision model for active service system is set up.

By introducing the oversea s advanced technology,according to the various factors which impact gas pipeline integrity,an analysis is made of the integrity assessment of gas pipeline in service from three aspects:safety,reliability and risk.

Date of domestic and international show that the economic loss caused of the harms of enduring disease of the bridge structure is very huge, and along with variety of environment, growth of service time , raise of function request, The durability problem of in service RC bridge is more and more outstanding.