隔震与非隔震支座对混凝土箱梁桥地震易损性的影响

为评估隔震和非隔震支座对桥梁地震易损性的影响,以一座3跨连续混凝土箱梁桥为分析对象,首先建立采用铅芯橡胶隔震支座与非隔震型盆式橡胶支座下桥梁的数值模型,求得不同程度地震作用下墩顶与支座的最大位移响应;再定义转角延性比损伤指标,结合支座剪应变,分析桥墩和支座的地震易损性情况;最后通过宽界限法建立全桥地震易损性曲线.研究结...

Seismic fragility of a concrete box-girder bridge with and without isolation bearings

To evaluate the seismic fragility of bridges with and without isolation bearings, the numerical models of a three-span concrete box-girder bridge with lead rubber isolation bearings and with non-isolation pot rubber bearings were established. The maximum displacement responses of pier top and bearing under different earthquakes were first analyzed. Then a damage index named ductility ratio of rotation angle was defined to estimate the seismic fragility of bridge piers and bearings. Finally, the wide-bound method was applied to analyze the seismic fragility of bridge system. The analysis results demonstrated that the bearing is the most vulnerable component, and the fragility of the bridge system is greater than pier and bearing. The failure probability of lead rubber bearing is obviously lower than that of non-isolation pot rubber bearing, thus it can be seen that the isolation bearing can effectively reduce the maximum displacement of pier top under earthquake, and the seismic vulnerability of pier with isolation bearings is better than that with non-isolation bearings.