The Effect Of Infill Walls On The Dynamic Behavior Of Reinfroced Concrete Frames

Infilled frame is a very common structural system used in the building structures. Existing research indicates that the infill walls have great effect on the capacity, stiffness and deformation behavior of frames. It is not always safe to ignore the effect of the infill walls, so it is necessary to take the effect of the infill walls on the frames into account when doing the seismic design of the frames. Although a lot of research about the behavior of the infilled frames have been done by many scholars all over the world,some problems are still to be solved. Main research work in this thesis is summarized as follows:(1) It is necessary to propose a reasonable and effective simplified model to analyze the effect of the infill walls on the frame. In this thesis, first, existing models are summarized and compared. For the infill walls without openings, three-strut model proposed by Wale are used in this thesis, and the determining method of model parameters is ameliorated. In addition, existing researches mainly focus on the infilled frames without openings, but, in fact, it is possible to have door or window on the walls because of the practical needs. So, it is necessary to do some study on the infilled frames with openings. In this thesis, the simplified models of the infilled frames with and without openings are proposed. Moreover, the validity of the proposed models are verified by modeling existing experiments.(2) The stiffness effect of the infill walls can make the soft storey effect occur in the infilled frames."Technical specification for concrete structures of tall building (JGJ 3-2002)"requires that too much difference of stiffness between neighboring storey should be avoided when designing the infilled frames. In order to avoid the soft storey effect induced by the irregular distribution of the infill walls, the best method is to control the ratio of the lateral stiffness between the soft storey and neighboring storey. Based on the proposed in this thesis and nonlinear time history analysis, the reasonable lateral stiffness between the soft storey and neighboring storey is given.(3) Furthermore, the stiffness effect induced by the infill walls makes the natural period of the frames decrease, which makes the earthquake forces put on the structures increase. The modification coefficient of the natural period will directly effect the reaction of the reinforced concrete frames under the earthquake, so...