不同比例板式楼梯对RC框架结构抗地震倒塌能力的影响

既存RC框架结构房屋,14开间,设有2部板式楼梯,原设计遵循GBJ11-89《建筑抗震设计规范》,但结构整体计算未带楼梯.以此结构为原型,缩略若干标准开间,形成了14开间、10开间和7开间的3组模型.整体计算考虑带楼梯和不带楼梯两种情形,采用MSC.MARC有限元软件建立了6个算例,进行逐步增量时程分析,研究不同比例楼梯对RC框架结构抗地震倒塌能力的影响.结果表明：带楼梯计算相对于不带楼梯计算,结构整体抗地震倒塌能力的计算值增大,且楼梯比例越大,计算值增大越多;带楼梯计算时,楼梯将首先发生局部破坏甚至倒塌,早于结构整体倒塌,而楼梯间的框架柱亦成为结构中的薄弱部位.

Influence of Different Proportion of Plate Stairs on Seismic Collapse Resistance of RC Frame Structures

A servicing RC frame building was designed with 14 bays and 2 plate stairs, and the design originally abided by GBJl1-89 ＂Code for Seismic Design of Buildings＂, and did not consider the stairs in the structure integrated calculations. As a prototype, this structure is abbreviated by some standard bays to form 3 new groups of models of 14-bays, 10 -bays and 7-bays.The new structures＂ integrated analyses take consider two cases of calculations with stairs and without stairs. Using the finite element software MSC.MARC to model 6 examples, and by means of incremental dynamic analysis, research the influence of different proportion of stairs on seismic collapse resistance of RC frame structures. The results show that, firstly, in contrast to calcu- lations without stairs, calculations with stairs derive the higher computation value of seismic resistance capa- bility of whole structure, and the bigger proportion of stairs, the higher computation value ; secondly, during the process of calculation with stairs, the stairs will be first damaged and the stairs partial collapse will be earlier than the whole structure collapse, in the meantime, the frame columns surrounding the staircase will become the weak parts of the structure.