Seismic Analysis Of Large-Bay Frame Structure With Special-Shaped Columns By Time-History Method

In recent years, people have put forward the new request for the living conditions with the improvement of the living standard. As a result, the new system of reinforced concrete special-shaped column frame structure has appeared which has been applied in many provinces and cities in China because it offered the ideal living environment to user through the combining of architectural beauty and function of use. But this kind of structure system mostly is small-bay room (about 3.3m ), and research of the RC large-bay frame structure system with special-shaped columns is less, which has better function and better economic benefit. And most of study on frame structure with special-shaped columns is limited to district of 7 degrees. The majority has only carried on the research at elastic stage. So it is necessary to carry elastic and plastic analysis of large-bay frame structure with special-shaped columns by time-history method.The paper analyses three kinds of RC large-bay frames, which are frame with normal special-shaped columns, bottom concealed columns and bottom rectangle columns. Main research work are given as follows:1 .Nine three-dimensional finite element models are set up by space beam elements and shell elements by ANSYS. The nine models are three kinds of large-bay frames, the bottom of which is 3.9m, 4.2m and 4.5m high. Then the characteristics of self-vibration can be analyzed as the base of dynamical analysis.2.The elastic and plastic time-history dynamical analysis is done after seismic wave is input and characteristics of each frame under earthquake is discussed by comparison of maximal displacement of slabs of each floor, distribution range of displacement of each floor, story-drift, mean value of the extreme positive and negative displacement of the top floor and plastic deformation. Each analysis value of both frame with bottom concealed columns and bottom rectangle columns is less than that of frame with normal special-shaped columns. When the bottom floor is lower, the control of top displacement and the second floor story-drift of frame with bottom rectangle columns is less than frame with bottom concealed columns. When the bottom floor is higher, every analysis value of frame with bottom rectangle columns is less than frame with bottom concealed columns, except the plastic deformation of the third upgrade floor. Namely, seismic behavior of frame with bottomrectangle columns is better than frame with bottom rectangle columns when the bottom floor is higher.3. Integrating above conclusions, frame with bottom concealed columns is best to be adopted at the range of codes when the bottom floor is lower and frame with bottom rectangle columns should be paid the utmost attention to adopt at the range of codes when the bottom floor is higher when large-bay frame structure system with special-shaped columns is designed.