桩墩配筋率比对桥梁结构塑性区长度的影响

Influence of Pile-pier Reinforcement Ratio on Plastic Hinge Length of Bridge Structure

采用弹塑性纤维单元模型对某连续梁桥桥墩及桩基进行了考虑桩-土动力相互作用的非线性地震反应分析,分析了不同类型地震波作用下桥墩及桩基的动力响应,重点研究了不同桩墩配筋率比对结构塑性区开展程度及动力响应的影响。结果表明:随着桩墩配筋率比的改变,桥墩和桩基的反应塑性率呈现出不同的变化趋势,桩墩配筋率比的大小对桥梁结构的塑性区开展有显著影响;桥墩的配筋率大小不仅对桥墩塑性区开展有显著影响,而且对桩基的影响较大;不同类型的地震波对群桩基础桥墩结构的动力响应影响不同,长周期地震波对结构的影响最大,内陆直下型地震波次之,板块边界型地震波最小。

Using elastic-plastic fiber unit model for a continuous beam bridge structure and pile foundation, the nonlinear seismic response of pier and pile foundation considering pile-soil interaction was carried out and influences of the dynamic response of pier and pile foundation under different types of seismic waves were analyzed. The development of plastic zone and dynamic response of structure under different pile-pier reinforcement ratios were emphatically studied. The results show that with the pile-pier reinforcement ratio change, the response plastic ratios of pier and pile foundation show different trends~ pile-pier reinforcement ratio is an important factor of affecting dynamic characteristics of the bridge pier supported by group pile systems~ the pier reinforcement ratio not only impacts on development of plastic zone of the pier, but also impacts greatly on the pile foundation. In addition, different types of seismic waves have different effects on the dynamic responses for bridge pier structure with group pile foundation, and the long-period seismic waves are maximum, followed by inland direct seismic waves, plate boundary seismic waves are minimum.