A method for stochastic seismic response analysis of non-classically damped structures

A method to calculate the stationary random response of a non-classically damped structure is proposed that features clearly-defined physical meaning and simple expression. The method is developed in the frequency domain, The expression of the proposed method consists of three terms, i.e., modal velocity response, modal displacement response, and coupled (between modal velocity and modal displacement response), Numerical results from the parametric study and three example structures reveal that the modal velocity response term and the coupled term are important to structural response estimates only for a dynamic system with a tuned mass damper. In typical cases, the modal displacement term can provide response estimates with satisfactory accuracy by itself, so that the modal velocity term and coupled term may be ignored without loss of accuracy, This is used to simplify the response computation of non-classically damped structures. For the white noise excitation, three modal correlation coefficients in closed form are derived. To consider the modal velocity response term and the coupled term, a simplified approximation based on white noise excitation is developed for the case when the modal velocity response is important to the structural responses. Numerical results show that the approximate expression based on white noise excitation can provide structural responses with satisfactory accuracy~     

动力p-y曲线模型在桥梁桩基础分析中的应用

地震作用下土-桩-结构相互作用(SSPSI)是桥梁抗震领域的一个重点和难点问题。在介绍动力p-y曲线分析模型的基础上,通过与试验对比验证其合理性,通过参数敏感性分析确定其影响参数,并对其进行了进一步探讨。研究发现:动力p-y曲线分析模型可较为全面地描述SSPSI,砂土摩擦角是该模型的主要参数,自由场土体应尽可能取较大的长度,地震动强度影响土体进入非线性的程度。     

面向设计应用的地震动空间相干函数模型

本文对现有的常用地震动空间相干模型进行了总结,提出了一个新的面向工程抗震设计应用的形式统一的地震动空间相干函数模型,在此基础上推导出了多点地震反应谱和功率谱计算所需要的振型组合系数的解析表达式,避免了耗费时间的数值积分运算。本文模型与计算方法使多点地震激励下结构响应的计算时间减低至积分方法的1/20以下,使多点地震反应谱方法和多点地震功率谱方法在计算时间方面实用化。     

飘浮体系斜拉桥纵向抗震计算的单塔模型

通过全桥模型计算结果与单塔模型计算结果的对比,讨论了集中质量在塔上锚固区处堆聚位置,定义了一个结构动力特性和结构地震反应的修正系数,提出了飘浮体系斜拉桥塔纵桥向地震反应计算的单塔模型。多个工程实例的分析结果表明,采用单塔模型的典型误差在15%左右,精度可以满足工程抗震设计的要求,使桥塔的抗震计算得到简化。