Study On Nonlinear Seismic Response Analysis Method Of Reinforced Concrete Core-tube

At present, the steel-concrete hybrid structures have been applied to the tall buildings and super-tall buildings more and more widely in our country. The poor study on seismic behavior of the structures does not meet the needs of its development speed. So this paper gives mainly a nonlinear seismic response analysis method of reinforced concrete core-tube, which is key lateral-force-resisting member of the steel-concrete hybrid structures. The method lays a foundation to research further the seismic behavior and seismic design method of the hybrid structures.To give a reasonable and effective method of nonlinear seismic response analysis, two key problems should be solved. The one is to determine the reasonable nonlinear analysis model of concrete core-tube, and the other one is to select the nonlinear hysteretic model that can reflect true behavior of the core-tube. At first, the mechanics behavior of the concrete core-tube is analyzed. It is found that its mechanics behavior is similar to the shear-wall's. Therefore, by considering its mechanics behavior and analyzing current nonlinear analysis models of shear-wall, the multiple vertical line element model is determined as the nonlinear response analysis model of reinforced concrete core-tube. Secondly, the hysteretic models of horizontal and vertical springs in the multiple-vertical core-tube model are chosen. By analyzing the results of current concrete core-tube and some shear-wall tests at home and abroad, the features of shear hysteretic model of the core-tube are given. Compared with the current shear hysteretic models, the revised Takeda model with pinch is selected as the shear hysteretic model of the concrete core-tube. By analyzing current axial-stiffness hysteretic models of concrete structures, the axial-stiffness hysteretic model, which is given based on test results by Jiang Jinren, is selected as the axial-stiffness hysteretic model of concrete core-tube. And the two hysteretic models selected are improved so that they become more perfect. At last, the nonlinear seismic response analysis method of the core-tube is given by using the analysis model, and the corresponding analysis program is compiled on the basis of the large special computer program DRAIN-2D and added to DRAIN-2D. The program is proved to be reliable and-II-_____________________effective by three examples. The method in this paper can be used in steel-concrete core-tube structures and reinforced concrete frame-shear wall structures, and can be extended to use in reinforced concrete core structures and tube in tube structures.