Study On Advanced Maintenance Technology Of Urban Cable-stayed Bridges

In recent years,more and more attention has been paid to three-dimensional transportation by the urban designers.The urban cable-stayed bridge with its beautiful appearance and the advantages of large span,stand out in the numerous bridge.Because of the complex structure of the cable-stayed bridge,it will face many risks in its whole life cycle.However,at present,the evaluation methods and maintenance methods of the urban cable-stayed bridges are mostly based on the technical conditions of components,and the risk sources have not been fully considered.Therefore,based on the existing research results at home and abroad,this paper studies the comprehensive evaluation method of the urban cable-stayed bridges and the formulation of optimal maintenance strategy.The main research contents and conclusions are as follows:(1)Based on the construction scale,body design,location characteristics,natural conditions and operating conditions of the urban cable-stayed Bridges,the risk sources are further divided into 30 sub-items.According to different kinds of risks,the safety limits of each risk factor are analyzed,and the corresponding detailed rules of scoring are made.(2)The analytic hierarchy process(AHP)is used to analyze the weight of each risk.The analysis results show that the importance of the five risks is ranked from high to low,namely,operation risk(0.314),bridge design risk(0.286),natural condition risk(0.255),bridge location characteristic risk(0.104)and construction scale risk(0.041).(3)The fuzzy evaluation method based on urban cable-stayed bridge is studied by introducing fuzzy theory.By using the weighted average method,and considering the assessment results of bridge technical conditions,risk fuzzy assessment results and risk scoring results,the comprehensive assessment method of the urban cable-stayed Bridges is studied.(4)This paper studies the working mechanism of the optimal maintenance strategy model of the urban cable-stayed bridge based on reliability index,condition index and double index,and uses MATLAB to edit the optimal maintenance strategy program and make the working interface.(5)Taking a cable-stayed bridge in a certain city as an example,the comprehensive risk assessment of the bridge and the formulation of optimal maintenance strategy are analyzed.The analysis results show that the introduction of fuzzy theory can improve the risk level of the project;considering the technical condition of the bridge can make the result of risk assessment more close to the actual risk condition of the project;the optimal maintenance strategy based on a single index is superior to the one based on double indexes in terms of maintenance frequency and maintenance cost;preventive and maintenance measures taken before risk deterioration can reduce maintenance by 1 times and save about 18.6 % ~ 44.8 % in the whole life cycle.