填充墙既有减小结构周期而增大地震力的不利一面,也有增大结构层间侧移刚度的有利一面.汶川地震中,具有填充墙的底层薄弱结构破坏严重.根据等效刚度原则,把具有填充墙的框架转化为等效的纯框架,对七层底层薄弱结构进行小震下的弹性分析和大震下的弹塑性Pushover分析.结果表明,尽管填充墙使得结构中、上部层间角位移不同程度地减小,但却使得底层相对更加薄弱,层间变形比不考虑填充墙时大,填充墙对于底层薄弱结构有不利的影响.
In the frames filled with infill walls, infill walls have both negative effect (decreasing the structural period and increasing the earthquake action) and positive effect (increasing the story lateral stiffness) on the structure. There were a lot of failure phenomena occurring in this kind of building in Wenchuan earthquake. The method of equivalent stiffness is employed to transform the original frame with infill walls to the equivalent frame, and the elastic analysis under the minor earthquake and nonlinear static Pushover analysis under the severe earthquake of a 7-story building structure with the lower weak story is performed using the proposed method. The results show that the infill walls may reduce the story drift ratio of the middle and upper stories to some degree, however, they made the weak lower story much weaker relatively and cause the drift ratio of the weak story to become larger. Thus, the effect of infill walls is negative to the structures filled with infill walls with the lower weak story.