Seismic vulnerability analysis of regular continuous girder bridges
ZHANG Ju-hui1，GUAN Zhong-guo2
1.University of Shanghai for Science and Technology, Shanghai 200093, China；2.State Key Laboratory For Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China
Abstract：Structural performance indices of the regular continuous girder bridges under different damage states were discussed and constructed by displacement ductility ratio. Based on the OpenSees platform, a structural dynamic analysis model was established by using the nonlinear fiber beam elements. 100 earthquake ground motion records were selected, and the nonlinear time-history analysis was performed, thus the fragility curves under different damage states were constructed. Through parametric analysis, the effects of pier height, bearing types and transverse reinforcement ratios on the fragility curves were studied. The results show that the ductile development degree of the continuous bridge has a great effect on the structural seismic vulnerability. The fragility curves obtained under both minor damage and moderate damage seem to be very close; while under extensive damage, the bridge shows a good performance against earthquake forces. With the increase of the pier height, the lower level of damage probability of the structure is observed; meanwhile, the improvement in the fragility by using the plate rubber bearings is excellent for a short-pier bridge, but very limited for a high-pier one. The effect of increasing the transverse reinforcement ratio on fragility curves can be neglected for structural damage in early stages, but can significantly increase the structural capacity from collapse.
2014, Vol. 33 
