局部平均刚度比对底框结构抗震性能的影响

Influence of the local average stiffness ratio on the seismic performance of bottom frame structures

为了研究平面内刚度不均匀性对底框结构抗震性能的影响,提出了局部平均刚度比的概念。建立具有不同局部平均刚度比的ABAQUS有限元模型,并进行弹塑性时程分析。分析结果表明：平面内刚度分布不均匀会导致局部墙体严重破坏,从而影响结构整体的安全性。局部平均刚度比作为衡量同一楼层平面内局部区域刚度大小的指标,其值过低时会造成该区域抗侧刚度不足,墙体破坏严重;过高时会造成薄弱部位转移,对平面内其他区域的墙体产生不利影响。综合分析以上结果,建议底框结构的局部平均刚度比控制在0.66-1.30,该结论可作为我国抗震规范平面内刚度分布的补充规定,为结构设计提供参考。

In order to study the influence of uneven in-plane stiffness distribution on the seismic performance of bottom frame structures, a concept called local average stiffness ratio is proposed. Finite element models with different local average stiffness ratios were designed in ABAQUS, then elasto-plastic time-history analysis was carried out. The analysis results show that the uneven distribution of in-plane stiffness can lead to serious damage to local walls and accordingly affect the safety of the whole structure. The local average stiffness ratio, as a measurement index of local area stiffness in the same floor plane, will cause lateral stiffness insufficiency and serious damage to the wall when the value is too low. When the value is too high, it will cause movement of the weak spots, with an adverse effect on walls in other areas in its plane. Through a comprehensive analysis of the results, it is suggested that the local average stiffness ratio of bottom frame structures should be controlled in the range of 0.66- 1.30. This conclusion can be used as a supplementary provision for in-plane stiffness distribution for seismic design, and provides a reference for design methods in this kind of structure.