钢筋混凝土框架顶部钢结构加层的抗震性能分析

Analysis of seismic resistance of integral structure after adding steel storeys on top of concrete frame

采用钢结构加层后,结构的整体质量、刚度、周期、阻尼比等都发生较大的变化。仅对加层部分结构进行计算分析是不安全的,应进行结构的整体分析。本文采用有限元软件ANSYS,对某4层钢筋混凝土框架结构办公楼顶部加2层纯钢框架的抗震性能进行分析,并在此基础上讨论了不同加层层数的整体框架模型、不同阻尼比ζ和有侧移及无侧移框架形式对结构整体抗震性能的影响分析。计算表明,由于加层后结构周期加长,整体框架的底层层剪力变化较小。

Significant differences occur in the mass, stiffness, period and damping ratio after adding steel storeys on the top of the original building. It is necessary to analyze the integral structure due to the unreliability of calculating the adding storeys independently. This paper compares different integral models by changing the number of adding storeys , damping ratio and adopting adding storeys with or without braces on the top of the original four - storey concrete frame by finite element analysis （FEA） software ANSYS. The result shows that the total bottom shear force of the structure varies inconspicuously as a result of the elongation of the period.