混合结构时程分析中的阻尼比计算研究

摘 要： 混合结构由于其建筑及功能上的种种优点，在现代建筑中得到广泛应用。对这类结构进行分析时，主要有两个问题：一是在考虑不同材料的情况下，结构的整体阻尼比如何计算；二是在整体阻尼比的计算结果下，如何针对小阻尼材料进行修正。本文以高楼顶加钢塔的这一混合结构形式为例，建立了一种非比例阻尼矩阵的构造方法，计算结果表明该构造方法得到的振型阻尼比可以较好的反映对主体结构和顶部钢塔影响最大的4阶振型的耗能特点。此外，本文基于反应谱法推导了顶部钢塔在整体阻尼比（第一阶主振型的阻尼比）计算下的误差，在此基础上，给出了相应的修正公式，最后采用上述方法分析了洛阳某高层顶部钢塔的地震响应。

Damping ratio of composite structures used in time-history analysis

There are two main problems in the study of damping effect of composite structures:the first is how to calculate the damping ratio of the whole structure when adopting different materials;the second is how to modify the low damping material after obtaining the integral damping ratio of the whole structure.Taking the high-rise building with steel tower on top as an example,a construction method of non-classical damping matrix was proposed.The result shows the damping ratio based on this matrix can reflect the energy dissipation of 4 orders of modes which play the most important influence on the main structure and the steel tower on top.By the response spectrum method,the inaccuracy of the steel tower’s result due to using the calculated integral damping ratio was deduced and a modification equation was provided.The comparison with the accurate result shows the modification factor obtained by the equation has certain reference value to the earthquick response calculation.