考虑余震影响的RC框架结构抗震设计方法

历史地震表明强余震会进一步增大结构的破坏程度甚至使其倒塌,但是我国乃至世界上的所有抗震设计规范均只考虑主震作用而没有直接考虑余震影响.为提出能有效考虑余震影响的抗震设计方法,文章基于主余震设计谱和主震设计谱共设计了12个钢筋混凝土(RC)框架结构.选取50条实际主余震地震动对所有结构进行增量动力分析进而得到结构倒塌易损...

Seismic design method of RC frame structures considering effects of aftershocks

 Historical earthquakes have confirmed that aftershocks would increase the damage of structures and even make them collapse, but all the seismic design codes in the world cannot consider the effects of aftershocks directly. A total of 12 reinforced concrete (RC) frame structures were designed based on mainshock-aftershock design spectrum and mainshock design spectrum. The collapse vulnerability of RC frame structures was studied with 50 as-recorded manishock-aftershock ground motions. The collapse margin ratio CMR of mainshock-aftershock affected and mainshock affected structures was compared and analyzed. It was found that the CMR of mainshock-aftershock affected structures was smaller than that of mainshock affected structures. In order to realize the collapse margin equivalence of structures, the prediction equation of Sa, 50% collapse is firstly proposed with basic period T1 as variable. Then collapse margin equivalent equation is derived, and it is numerically solved with design spectrum. The prediction equation of T1,A is lastly proposed with T1,M as variable under the collapse margin equivalent condition. The collapse margin equivalence of mainshock-aftershock affected and mainshock affected structures can be realized by comprehensively using the prediction formula and mainshock-aftershock design spectrum.