Vulnerability Of Bridge Network Based On Probability Seismic Hazard Analysis

The post-earthquake performance of the traffic network is of great significance to reduce the loss of regional disasters and to speed up the reconstruction.After the earthquake,the damage of the bridge structure will bring about part or even the entire traffic network interruption,seriously affected the post-earthquake relief work.This study initially established a set of assessment process which can determine the reliability of the entire traffic network and provide reference for rescue action to the road network system managers and government decision-making departments.Firstly,in this paper,the probabilistic seismic hazard analysis method is used to simulate the source and path attenuation,and combined with the random characteristics of the bridge material parameters,the calculation method of the vulnerability curve of the pier and the bearing structure is proposed.Then,the first-order boundary method is adopted,and vulnerability curve of pier,bearing and other structural components establish the vulnerability curve of the bridge system.Then,according to the vulnerability curve of the bridge system,the damage level of the bridge is evaluated and the traffic capacity of the road correspond the traffic network is calculated.Combined with the traffic balance distribution model with road capacity constraints,the method of calculating traffic network vulnerability is taken under the evaluation standard of the travel cost.And then discuss the vulnerability of the entire traffic network changes from the earthquake recurrence and road network demand capacity.The results show that these two factors have a certain impact on the vulnerability of the entire traffic network.Finally,due to the deficient age of concrete and an integral part has not yet formed between the components in the aftershock area,so there are always a lot of risks existing in the bridge construction process.This paper is based on the previous earthquake record,regress the probability model of the aftershock,and define the damage index of the bridge pier,such as cracking failure,minor damage,moderate failure,serious damage and complete damage,and put forward a method of the vulnerability under the bridge cantilever construction process after the earthquake.The results show that the probability of cracking destruction is nearly 40%in the whole bridge construction process,and the probability of overturning is less than 5%.Therefore,the construction process of the bridge after the earthquake in the aftershock area should pay more attention to the slight damage.