Study On The Nonlinear Seismic Response Of Reinforced Concrete Frame With Specially Shaped Columns

The reinforced concrete structure system with specially shaped columns is a system widely adopted in residential structure due to no exposed beams and colulmns in the room. However, due to the fact that there is not a mature method or tool designed for its nonlinear analysis, the research on seismic performance is mainly carried out through structural experiment, but the experimentation is very useful at studying the structural member and small-scale structure. As to integrated structure, the quantitative research on seismic performance is far from enough. Therefore, the convincing data can not be provided for the set-up of the relevant industry standards. This paper is part of the National Natural Science Fund project ″researches on 3D nonlinear seismic response analysis methods and integrated seismic performance of reinforced concrete structure with specially shaped columns″(Project No. 50478067). Based on the program for 3D nonlinear seismic response analysis of RC frames which developed on the beam-column element of fiber model, it aims to carry out the 3D nonlinear seismic response analysis on RC frames with specially shaped columns designed the codes, examine integrated seismic performance under the fortification and rare seismic actions, give a primary evaluation on the structure to see if it achieves the predetermined seismic aims, and offer some reference data for the seismic design on RC frames with specially shaped columns. This paper centers on aforementioned problems, the main achievements are as follows: ①By the beam-column element of fiber model based on nonlinear finite element flexibility method, the RC L,T,十-shaped columns under cyclic loading have been analyzed throughout the process and the analysis results have been compared with the experimental ones , which shows the element is applicable for nonlinear analysis in the member level. ②By the beam-column element of fiber model based on nonlinear finite element flexibility method, the RC L,T,十-shaped columns of different axial compression ratio under cyclic loading have been analyzed and the analysis results have been compared in aspects of strength, stiffness and ductility of different kinds of specially shaped columns in different horizontal direction. ③According to the actual code and technical regulation, two representative regular reinforced concrete frames with specially shaped columns have been designed, which respectively situated at the area of fortification intensity 7 and 8. Subsequently, the nonlinear seismic response analysis has been carried out for the structure by inputting ground motions in one direction. After summing up the calculation results, this paper have examined integrated seismic performance of the structures under the fortification and rare seismic actions and given a primary evaluation on the structure to see if it achieves the predetermined seismic aims. ④According to the actual code and technical regulation, two representative irregular reinforced concrete frames with specially shaped columns have been designed, which respectively situated at the area of fortification intensity 7 and 8. Subsequently, the nonlinear seismic response analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results, this paper have examined integrated seismic performance of the structures under the fortification and rare seismic actions and given a primary evaluation on the structure to see if it achieves the predetermined seismic aims.