The Fuzzy Comprehensive Durability Evaluation And Remaining Lifetime Forecast Of The Existing Two-way Curved Arch Bridge

The Chinese unique two-way curved arch bridges, built in the 1960s and 1 970s, suffered from different degree of damage and gradually exposed their defe cts after in operating for many years.These defects that the style of bridges are poor in overall performance,have less reinfocement and low design load make the bridge hardlly play their important role in traffic.It is necessary to repair an d strengthen the existing two-way curved arch bridges to restore and improve th eir practical function.The measures taken to repair and strengthen the bridges ar e determined according to the actual working condition。This article forms a process:bridge inspecting-durability evaluation-remaining lie forecast to analyse th e actual working condition and the possible future development of the two-way curved bridge comprehensively.Through the article we can get reliable technical information and reference for the maintenance and strengthening of the old brid ges. The research process and results in this article are described below:l.In order to learn the actual working condition of the curved arch bridges, a two-way curved bridge is inspectsed according to the existing regulations an d standards.The content inclues the quality inspecting of the whole bridge and s tatic load test. We can find the desease and the cause for the desease by the b ridge inspecting and also can evalue the actual working congditiong under the e ffect of test loads by the static load test.2.According to the results of bridge inspection and the existing research res ults,we can find that there are many factors which have influence on the durabi lity of the bridge. The two-way curved arch bridge is composited by four parts which are the spandrel arch,the pier(abutment) and substructure,the main arch r ing,others accessories equipments.The article build up a model for the fuzzy co mprehensive durability evaluation of the two-way curved arch bridge and adapts two-grade evaluation.Grade one evaluates the durability of every compositive p art,and grade two evaluates the durability of the whole bridge structural accordi ng to the result of grade one. Finally the artcle adapts the approach degree to correct the result of fuzzy comprehensive durability evaluation.Through the fina 1 results,it is obvious shown that the fuzzy comprehensive analysis method is fe asible and can be applied to the evaluation of bridge durability.3. The reliability of main arch ring is equel to that of the whole two-way curved arch bridge structure.according to the principle, the artile analyzes the de scending tendency of the reliability of main arch ring using the dynamic reliab ility and establishes its attenuation curve.It is appropriate to take the moment as the end of the life forecast of the bridge when the dynamic reliability reaches to the index of goal reliability.The remaining life of the bridge is equel to the result that the ending time minus how long the bridge is in service.