Performance-Based Seismic Evaluation For Infilled Frames

At present, the multi-storey reinforced concrete frame structures is widely used in China, which is often used brick wall, brick or other masonry materials separated or external enclosure. Scientific evaluation and understand the seismic performance of the structure, Minimizing the loss of earthquake damage and protect the people's life and property safety, is of great significance. In the lateral loading , the infilled walls and frame work together, infilled walls alter the strength and stiffness of the structure. However, in practical engineering design and structural assessment, often do not consider such interaction, and assume that the full loads applied to frames. This simplified approach is not safe . because infilled wall increased lateral stiffness of structure, that might lead to large earthquake response. Centering round the seismic evaluation of inFilled frames, the dissertation involves the following work.This paper introduces the performance of infilled frames under lateral load, gives an illustration on the factors that affecting the stiffness and strenth capacity of structure , introduces the mode of infilled frames, and analyses the seismic performance of the structure.The paper sums up various analytical methods of the domestic and foreign researchers , discusses the merits and demerits of each method to calculate the infilled framse ,thinks the equivalent diagonal strut model is applicable to the calculation of the analysis of macro structure. In order to achieve the nonlinear relationship of infill walls ,the paper establishes the relationship of axial force—deformation of equivalent diagonal strut.Based on the analysis of the research and rules on performance level of domestic and foreign literatures, seismic performance level are proposed for infilled frames structure. The evaluation quantization indexs of the different performance levels of infilled frames structure are established by analyzing the behavior of infilled frames under lateral load and the test data. With the aid of finite element analytical software ETABS, by using two types of analysis model , make the nonlinear static analysis for three infilled frame structures. Capacity spectrum method was used to achieve the seismic response of the structure.Then give the evaluation of the structures according to the inter-story drift ratio .It is concluded that indexs of the different performance levels expressed by the inter-story drift ratio proposed in this paper can reflect the seismic performance of structure.