基于频率合成的桩基础独柱桥墩横向振动基频的解析算法  

An analytical algorithm based on frequency synthesis method for calculating transverse vibration frequency of single column pier with pile foundation

作　　者：安里鹏[1] 李德建[1] 

机构地区：[1]中南大学土木工程学院,长沙410073

出　　处：《应用力学学报》2015年第4期524-529,699,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51378504);湖南省交通科技计划资助项目(201022)

摘　　要：采用桩基础的桥墩,在荷载作用下承台将产生一定的位移,即桩基础对桥墩下部约束是弹性的。此外,桥墩横向振动时,桥梁上部结构通过支座对墩顶又具有约束作用,在进行桥墩基频计算时应考虑墩底和墩顶的弹性约束。本文采用Rayleigh和Southwell频率合成法,将基频表示成各惯性元与复位元所组成的子系统的频率合成,导出了桩基础独柱桥墩横向自振频率的显式表达式。将根据具体实例与解析算式得到的结果与实测值、有限元方法计算值比较,结果表明:该公式计算值与实测值相比误差为1.7%,与有限元法计算值相比误差不超过4.31%,具有较高的精度。同时分析了不同参数对桥墩横向自振频率的影响,验证了Southwell频率合成法的正确性,对桩基础刚度参数的动力识别具有重要理论意义。A displacement would occur at the pile cap under the load from bridge pier, which means the restraint of the pile foundation to the pier bottom is elastic. In addition, bridge superstructure also plays an important role in restraining the displacement of pier top by bearing. Thus, these elastic restraints should be considered during the pier base frequency calculation. Based on the combination of Rayleigh and Southwell methods, the fundamental frequency of bridge pier could be decomposed into the summation of frequency of each subsystem consisting of inertia components and deformable components. Then according to the transverse vibration frequency analysis of a single column pier with elastic constraint boundary, the explicit expressions can also be derived. Compared with measured values and FEM computational results, results by the analytical algorithm possess superior precision because the relative errors are less than 1.7% and 4.31%, respectively. Effects of different parameters on the transverse vibration frequency of pier are also analyzed. The algorithm developed has important theoretical significance for the dynamic identification for the stiffness parameters of pile foundation.

关 键 词：桩基础 独柱桥墩 横向振动基频 频率合成法 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]