Analysis Of Overstrength Characteristics Of RC Shear Wall Structures

Structure overstrength plays an important role in improving the capacity of resisting collapse of structure during strong earthquake. But appropriately considering the structure overstrength can be used to reduce the level of seismic in structure design, and to make structure more rational. Structure overstrength has been taken into consideration in design codes of the United States, New Zealand and other countries. However, domestic research starts late and the study of structure overstrength in shear wall structures designed according to Chinese codes has not been reported. Based on the facts above, the main work finished in this paper is as follows:①Eight shear wall structures with different seismic fortification intensity and different stories are designed strictly according to Chinese codes, and these structures are analyzed by Perform-3D software to obtain overstrength factors. Furthermore, the overstrength capacity of shear wall structures designed strictly according to Chinese codes is studied quantitative.②Influence factors of structure overstrength considered in this paper include seismic fortification intensity, number of stories, bidirectional earthquake motion and so on.③In order to get a better awareness of the seismic behavior of shear wall structures designed according to Chinese codes, the structure overstrength characteristics of the eight examples under medium earthquake and large earthquake are studied in different ways.④Two shear wall structures are designed according to Chinese codes. In order to preliminary study to structure overstrength of Chinese codes, the overstrengh factor of the two examples above is assumed as 2. Material dosage pre-and post consideration of overstrengh factor are compared. Aseismic performance under large earthquake is researched.Throughout the work above, main conclusions are obtained as follows:①Shear wall structures designed strictly according to Chinese codes show different overstrength degrees, which are significantly lager than the existing research results of RC frames. Based on the research above, minimum value of overstrength factor is conservatively estimated as 2 for shear wall structures strictly designed according to Chinese codes.②As number of stories is increased, the overstrength factor is gradually increased; As the seismic fortification intensity is increased, the overstrength factor is gradually decreased; After considering bidirectional earthquake, the overstrength factor decreased, but the decrease range is small.③Because of structure overstrength, some part of the structure go into plastic with a small range uder medium earthquake, a considerable potential level exists between the large earthquake and level and collapse.④After considering overstrength factor, the dosage of concrete and steel decreased, and the decrease range of the structure in high-intensity earthquake region is bigger than that of the structure in low-intensity earthquake region.