【摘要】 以一座上部布置钢筋混凝土框架结构的三跨预应力混凝土连续刚构景观廊桥为例,采用基于传统可靠度理论的方法对结构的地震易损性进行研究。通过建立结构的空间有限元模型,考虑了上部建筑结构对桥梁结构的影响,对其进行了非线性动力时程分析;在基于位移破坏准则的基础上定义桥墩、支座的损伤指标,同时考虑地面运动和结构材料的不确定性,以地面峰值加速度作为自变量,分别形成了桥墩、支座的易损性曲线;最后运用一阶界限法分别计算考虑建筑结构和不考虑建筑结构桥梁系统易损性曲线的上下界,分析了上部建筑结构对桥梁系统易损性的影响,对全桥的抗震性能进行分析评估。结果表明:上部建筑结构对桥梁系统的地震易损性影响显著,使桥梁发生严重破坏和完全破坏的概率明显增大。更多还原

【Abstract】 Taking a 3-span of RC continuous rigid frame landscape covered bridge with superstructure of reinforced concrete frame for instance,the seismic fragility analysis is performed by using the method based on traditional reliability theory. The nonlinear dynamic time history analysis is performed on the basis of the established spatial finite element model of the structure considering the influence of the superstructure on the bridge. The damage indexes of the pier and the bearing are defined based on the displacement failure criterion. Considering the uncertainties of ground motion and structure material, taking peak ground acceleration as independent variable,the fragility curves of piers and bearings are obtained. Finally,the upper and lower limits of bridge system fragility curves including superstructure and not including superstructures are calculated by using the first-order boundery method. The influence of the superstructure on the bridge system fragility is analyzed,and the seismic property of the bridge is assessed. The result shows that the superstructure affects the seismic vulnerability of the bridge system significantly,which make the probability of serious damage and complete damage to the bridge increase dramatically.更多还原