Seismic Vulnerability Analysis Of Wooden-Concrete Beam Bridge

Bridge is an important part of highways or railways,and it is a key hub.Under earthquakes bridges are often most likely to be damaged,such as the 7.9 magnitude earthquake in Yushu,Qinghai,China in 2010,and the 9 earthquake in Fukushima,Japan,in 2011.To decrease secondary disasters after earthquake,bridges play an important role in earthquake relief.Seismic risk assessment of bridge is based on seismic vulnerability analysis of bridge.Seismic vulnerability analysis of bridge is helpful to predict the damage of bridge structure when earthquake occurs,and it is also beneficial to bridge seismic design.Wood concrete composite structure is a new type of structure.Compared with reinforced concrete structure,wood concrete composite structure has the characteristics of low energy consumption,light quality,good seismic performance and so on.The vulnerability of wood concrete composite bridges under earthquake is not studied and analyzed in China.It is very necessary and meaningful to carry out the research.Vulnerability curve is an effective tool in seismic vulnerability analysis,and is widely used in various countries.In this paper,a practical wooden concrete bridge is taken as an example,and the following aspects are mainly studied:(1)analyze the vulnerability of two bridge members with bolt connections and pier columns.Determine the relationship between the damage grade and the damage index of the bolt connection and the pier column.The ground peak acceleration(PGA)is used to analysis parameter for the ground motion.According to the structure of the bridge site conditions selected 100 earthquake waves.Using Midas Civil to build the finite element model of the bridge,make nonlinear seismic dynamic time history analysis of the bridge structure,get the maximum displacement of the top of the maximum displacement and pier seismic waves corresponding to each.(2)analysis the seismic vulnerability of wood concrete composite bridges,combined with the damage index of bridge structure analysis of the seismic vulnerability of bridge structure,corresponding to different seismic damage probability structure strength.The vulnerability of the reinforced concrete bridge with the same structure size is analyzed.compared the seismic performance with wood concrete composite bridges and reinforced concrete bridge.(3)analysis the seismic vulnerability of wood concrete composite bridges with diffrent parameter.On the basis of other conditions,parametric analysis is carried out for the vulnerability of bridge structure,and the influence of bolt connection spacing layout,pier height and superstructure quality on structural vulnerability is studied.(4)Combined the analysis result taht vulnerability parameters of the wooden concrete composite bridge.It is shown that reducing the bolt spacing can improve the seismic performance of the bridge.Under the reasonable size,the higher the height of the pier and the smaller the upper mass,the seismic performance of the bridge is better.