Approximate Method for Transverse Response Analysis of Partially Isolated Bridges
Approximate Method for Transverse Response Analysis of Partially Isolated Bridges
复制标题
部分隔震桥梁横向响应分析的近似方法
DOI：
10.1061/(asce)be.1943-5592.0000473
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发表时间：
2013
影响因子：
3.6
通讯作者：
L. Sarno
中科院分区：
文献类型：
--
作者：
G. D. Corte;R. Risi;L. Sarno
隔震桥梁的现行分析程序经常使用等效（近似）线性化方法来表示非线性隔震/耗能装置的响应。线性化允许标准的线弹性分析方法，例如，反应谱法，以方便地用于设计目的。线性化方法本质上是一种迭代方法，这意味着需要反复校正和分析数值有限元模型。用封闭形式的方程来表示结构位移模式和结构元件的恢复力，可以实现进一步的简化。本文探讨了这种可能性，参考部分隔离连续桥梁，即，桥墩有隔震装置，桥台有铰接支座。讨论了高次振动模态对系统响应的作用和影响，并提出了一种近似计算方法。利用响应时程分析的结果，提出了一种改进的经典Jacobsen近似的有效粘性阻尼比。后者进行了二维数值模型的五个案例研究，从一个真实的现有的桥梁应该是孤立的摩擦摆装置。近似预测与反应历史分析结果的比较，并进行了讨论。为了比较，还对既有桥梁的三维数值模型进行了非线性动力分析。
Current analysis procedures for seismically isolated bridges frequently use an equivalent (approximate) linearization approach to represent the response of nonlinear isolation/energy dissipation devices. Linearization allows standard linear elastic analysis methods, e.g., the response spectrum method, to be conveniently used for design purposes. The linearization approach is by nature an iterative method implying the need to repeatedly correct and analyze a numerical finite-element model. A further simplification could be achieved using closed form equations to represent (1) the structure displacement patterns and (2) the restoring forces from structural elements. The paper explores such a possibility with reference to partially isolated continuous bridges, i.e., bridges with isolation devices at piers and pinned supports at abutments. The role and effect of higher modes of vibration on the system response are discussed, and an approximate method is proposed to account for such effects. An improvement of the classical Jacobsen’s approximation for the effective viscous damping ratio is also proposed using the results of response history analyses. The latter are carried out on two-dimensional numerical models of five case studies, generated from a real existing bridge supposed to be isolated with friction pendulum devices. Comparison of approximate predictions with response history analysis results is presented and discussed. Nonlinear dynamic analyses of a three-dimensional numerical model of the existing bridge were also carried out for comparison purposes.