A Comparison Of Seismic Behavior Between Specially Shaped And Rectangular Column Frame Structures

The reinforced concrete structure system with specially shaped columns is a system widely adopted in residential structures due to no exposed beams and columns in the room. Presently, theoretical research and experimental study on specially shaped column units are systematical and mature. The research on seismic performance of the specially shaped column structure is mainly carried out through structural experiment and elastic analysis. The experiment mainly focused on columns or planar structures. The quantitative research on seismic performance of the integrated structure under different degrees of intensity is far from enough.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 by the code and specification, examine integrated seismic performance under the fortification and rare seismic actions, analyze the forces and deformations of the fibers in the units, and offer some reference data for the seismic design on RC frames with specially shaped columns. Meanwhile, by the 3D nonlinear seismic performance results of the structure with specially shaped columns and structures with rectangular columns, the seismic behavior of the two types of structures is compared.This paper centers on problems mentioned above, the following tasks are conducted:①By the beam-column element of fiber model based on nonlinear finite element flexibility method, the RC L,T,十-shaped columns of different axial compressions and directions under cyclic loading have been analyzed throughout the process and the analysis results have been compared with the rectangular columns.②According to the current Chinese code and technical specification, some frame structures with rectangular columns and specially shaped columns are designed respectively based on the criterion of the same section area, moment of inertia, initial rigidity of the specially shaped frame structure.③Using the program of fiber beam-column element based on flexibility method of finite element, nonlinear dynamic analysis is taken to analyze the two types of structures. The response of structures (such as story drift and torsion varying rules) is obtained under the fortification and rare grand motion. Still, the crack and yield rules of the main elements of the structures are compared by analyzing the stress and strain data of section fibers. So the change rules of the nonlinear seismic behavior of the two kinds of structures are obtained and some advices are provided for the seismic design of the specially shaped column structures and revising of the related specifications.