罕遇地震弹塑性静、动力分析方法中结构阻尼问题探讨

On damping in elastic-plastic static and dynamic method under rare earthquakes

本文针对罕遇地震弹塑性静、动力分析方法中结构的阻尼问题进行了一些算例和理论方面的探讨。总结了现有"规范"对于结构阻尼方面的规定;针对实际的高层混凝土和高层钢结构算例,探讨了各性能设计阶段结构等效阻尼比的变化情况,以及弹塑性阻尼对于结构静力推覆分析和能力谱方法计算结果的影响;探讨了不同的阻尼比对于罕遇地震弹性和弹塑性动力时程分析结果的影响;指出了将Rayle igh阻尼自然推广到弹塑性动力时程分析中所存在的问题;本文提出了实时阻尼比概念,通过算例分析表明可以较好地改进罕遇地震弹塑性动力时程分析中的阻尼问题。

The authors discuss the damping in elasto-plastic static and dynamic method under rare earthquakes with some examples. We study the regulations about damping in Chinese Seismic Code. By using the concrete and steel structures as examples, we discuss the effect of equivalent damping ratio in pushover method and capacity-demand- diagram method and the effect of damping ratio in elastic and elasto-plastic dynamic time history method. We point out the problems in extending the Rayleigh damping to elasto-plastic dynamic time history method. Finally, we provide an improved method of damping for elasto-plastic dynamic time history analysis.