The Time-History Analysis Study Of R.C. Frame With Special-Shaped Columns In Seismic Response

The reinforced concrete (R.C.) frame with special-shaped columns is a new structural system in recent 20 years. It's welcome with no prominence on the wall, enlarging useful chamber area, lightweight, according with the direction of walll material reformation. There is much test research about special-shaped column frame structure now, but so lack about its elastic-plastic performance theory research in the strive earthquake.This paper used the finite element analysis software ANSYS to analysis the dynamical-modes and elasto-plastic responses of the R.C. special-shaped columns frame construction, and then contrasted the calculated results with the test results. The results of the dynamical-modes and themaximal displacements of slabs of each floor for the calculating mode were well consistent to those of the test. It showed that the calculating models used by ANYSY were reasonable for the seismic response of R.C. special-shaped columns frame construction in this paper.Finally, in order farther to study the nonlinear eismic response of R.C. special-shaped columns frame construction, the author chooses a representative residential building scheme and gets a section to establishe two frame model of one special-shaped column frame with bottom rectangle columns and one pure special-shaped column frame.The elastic-plastic time-history dynamical analysis is done by the finite element program ANSYS after ELCENTRO 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 frame with 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 normal special-shaped columns. When the bottom floor is higher, every analysis value of frame with bottom rectangle columns is less than frame with normal special-shaped columns except the plastic deformation of the third upgrade floor. Namely, seismic behavior of frame with bottom rectangle columns is better than frame with normal special-shaped columns when the bottom floor is higher.Some problems such as the element model, the hysteresis model in the nonlinear time-history analysis of R.C. structure are summarized in the paper. According to the result of 3-dimension elasto-plastic time-history analysis, the author compares the seismic capability of two structures. The conclusions are of referential values for seismic design for similar structures.