预应力高桩码头振型反应谱抗震分析

Modal response spectra seismic analyses for prestressed piled wharf structure

高桩码头结构非线性地震时程分析时由于桩群数量众多,计算量过大,需要采用简化分析方法.首先介绍了超级桩的概念,将结构的桩群分组形成超级桩,用多个超级桩码头结构替代原结构,超级桩的刚度取为采用pushover分析得到的高桩码头力-位移曲线上对应于目标位移的割线刚度,阻尼采用等效阻尼,对超级桩模型进行弹性振型反应谱分析求解最大目标位移.将算例简化方法分析结果与非线性时程反应分析结果进行了对比,发现数值比较接近,表明超级桩模型可以用于估计地震下高桩码头的最大位移值,从而减少计算量.

Nonlinear seismic time history analyses of piled wharf structure will result in unacceptable matrix sizes due to a large number of piles.As an alternative,the structural characteristics of a wharf segment may be modeled by using the super-pile.The concept of super-pile is introduced at first.Super-pile locations of simplified model that represents original structure are determined by the locations of pile groups in defined areas.Force-displacement curve is calculated for piled wharf structure by pushover analysis,and super-pile model is constituted applying estimated secant stiffness corresponding with target displacement and effective damping according to force-displacement curve.Peak target displacement is evaluated by elastic modal response spectra analyses and compared with simulated results from nonlinear time history analyses.The calculated case indicates that approximate solution of maximum displacement can be evaluated effectively using super-pile simplified method,and computed amount is decreased simultaneously.