桥梁滞变非线性随机地震响应分析

对于含有滞迟剪切型单元的复杂多自由度系统，采用Bouc—Wen微分方程模型描述非线性抗力构件的滞变特性。以虚拟激励法代替常规的Lyapunov方程法结合等效线性化技术对平稳随机激励下系统的动力响应进行求解，激励谱可为白谱或其他任意形式。不但计算效率高，而且不引入除等效线性化之外的附加误差。对不同周期单自由度体系以数值模拟法验证了算法精度。在此基础上，对一座四跨桥进行了线性／非线性分析对比，得到合理的结果。

Seismic random vibration analysis of bridges with hysteretic nonlinearity

For complicated bridge structures with nonlinear shear-type elements, the hysteretic properties of the nonlinear elements are described in the Bouc-Wen differential equation model, and the pseudo excitation method, as a replacement of the conventionally used Lyapunov equation method, was combined with the equivalent linearization scheme to compute the seismic responses due to the stationary random ground excitations. The power spectral density of the seismic excitations can be of white noises or of any kind of non-white noises. This replacement leads not only to a much higher computational efficiency, but also to a good accuracy, in fact, no additional errors are caused due to the use of the pseudo excitation method. In other words, the errors are caused entirely by the equivalent linearization itself. The proposed method was tested by means of the Monte-Carlo simulations for a number of single degree of freedom systems with different initial periods. A four span reinforced concrete bridge was taken as a case study, and the comparisons between the linear and nonlinear analysis show the correctness of the proposed method.