Verifications Of Inelastic Seismic Response Performance Of Reinforced Concrete Structure With Specially Shaped Columns

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. The realization of performance objectives of structures under earthquakes at various levels depends on valid seismic fortification measures. These measures assure structures necessary ductility and hysteretic energy-dissipated capacity, make them dissipate stably earthquake energy through inelastic deformation and keep their carrying capacities to vertical loads and the stabilities as a whole under higher earthquake action levels. Series of design methods and seismic measures of our national code of concrete structure system with specially shaped columns for frame structures are mainly based on experiments, experiences from earthquake disasters and from engineering, and referred to correlative code of our nation. Up to now, these methods and measures still have not been verified by theoretical analyses. The availability of measures of internal forces adjustment and seismic detail can not been evaluated definitely.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, study seismic behaviors of structure under earthquake at various levels, then to verify the validity of seismic measures in the code of specially shaped columns of our nation through theoretical analyses.The main research work finished in this thesis is as followings:①Certain factors affecting the critical seismic measures for enhancing moment capacity of columns in frames and effective quantification methods were summarized and retrospectde②According to Chinese Technical Specification for Concrete Structures with Specially Shaped Columns (JGJ149—2006), the following frame structures were designed: A building of 3×2-span and 6-storey typical regular frame structures with specially shaped columns in Intensity Region 7(0.15g),A building of 3×2-span and 4-storey typical regular frame structures with specially shaped columns in Intensity Region 8(0.20g).③Based on the results of inelastic dynamic response analyses of these frame structures with specially shaped columns under certain ground motions with the program of fiber beam-column element based on flexibility method of finite element, the availability of the column moment capacity amplification measures, were verified preliminarily.From the research work stated above, the main conclusions can be obtained as followings:①The behavior of frame structure with specially shaped columns in Intensity Region 7(0.15g) and 8(0.20g) designed to the specification of our nation under the rare motion can basiclly achieve the requirements of seismic resistant, which could be judged from the structural integrative response and the element inactivation. The performance of structure in Intensity Region 7(0.15g) is better than that in Intensity Region 8(0.20g) under the rare motion.②The column moment capacity amplification measures is available in Intensity Region 8(0.20g) with Seismic Design CategoryⅡ, but it is not enough for the column base in bottom floor. As for the effect of column moment capacity amplification measures in Intensity Region 7(0.15g), it is better with Seismic Design CategoryⅢthan that with Seismic Design CategoryⅡ.