独柱墩T形刚构桥地震反应分析

针对目前城市桥梁通常采用的独柱墩连续梁桥的受力和结构设计存在的问题和缺陷,提出了2跨T形刚构桥梁结构形式,并对2种桥梁结构形式在构造和抗震性能方面的特点进行了对比.在构造方面,与连续粱桥相比,独柱墩T形刚构桥通过墩梁固结节省了支座,简化了伸缩缝的构造,增加了桥梁的横向稳定性,减小了横梁的受力.利用反应谱方法,推导了墩底固结等截面情况下T形刚构和连续粱桥简化模型的地震力和桥墩弯矩的解析表达式,并给出了不同周期范围内的2种体系地震反应的比较结果.采用桥梁的整体有限元模型,考虑桩土相互作用,对实桥进行了地震反应分析.研究结果表明,T形刚构采用墩梁固结能够显著降低地震力作用下桥墩和桩基的弯矩,提高了桥粱的抗震能力,简化了抗震构造.

Seismic Responses of T-shape Rigid-frame Bridges with Single-column Pier

Based on the existing problem and shortcoming of the continuous girder bridge with single column pier usually used in city,a two-span T-shape rigid-frame bridge is put forward in this paper,and the structure and seismic performance of the two systems are compared.Compared with continuous girder bridge,the T-shape rigid-frame bridge can save half of bearings,simplify the constitution of expansion joints,enhance the transversal stability and markedly reduce the stress of crossbeam at the mid-supports.Based on the response spectrum analysis method and simplified model,the analytical expression of the force and moment produced by horizontal seismic wave of the pier are deduced for continuous girder bridge and T-shape rigid-frame bridge under the condition that the bottom of pier is fixed and the section of pier does not change along its height.Using the expression,the seismic responses of the two system with different period are analyzed in detail.In addition,with finite element model of the global bridge and considering the influence of pile-soil interaction,the seismic responses of the two system are further studied.The studied results show that T-shape rigid-frame bridge can markedly reduce the moment of piers and piles,improve the anti-seismic capacity of bridge and simplify the anti-seismic measure.