Push-Over Analysis On The Frame Structure With Concrete-Filled Square Tubular Column And Reduced Beam Section

This paper is based on the experiment and theoretical results which from our workgroup. The static elastic-plastic Push-Over method is applied for the analysis of structure-Hangzhou Ruifeng International Business Building with reduced steel beam. According to the concrete floor, the ability to resist deformation of the frame structure is assessed.The development and research situation, the theory foundation, common lateral load models are described, specially introduce the capacity spectrum method provided by ATC-40.Because the SAP2000 is limited, the paper put forward a new format about reduced steel beam section. The principle of equal stiffness is based on equal area reduced of the beam section. With the finite element analyze software ANSYS, a new format about reduced steel beam section can be applied for founding the 3D-soild modles.The Push-Over method is adopted with the SAP2000 to analyse five-floor and twenty-four frame structures with concrete-filled square tubular column and reduced beam section in the seven and eight intensity. In the analysis the concrete floor affect the ability to resist deformation of the frame structure, and based on the results including the nonlinear base shear-roof displacement relational curves, the floor displacement, the story drift and so on, we can evaluated the seismic resistance of the structure. From these results, the new reduced format doesn't affect the integral stiffness of the frame structure ,while easing the stress concentration from the beam-column junctions and the plastic hinge is far away from the welded joint; Concrete-filled rectangular steel tubular(CFRT)structure display a better ductility and deformability; In the seven intensity, the structure in the paper meet the seismic design code of China-"Don't damage in the tremor; Don't collapse in big earthquake", however, the story drift without concrete floor approaches the maximum value from the seismic design code of China ;In the eight intensity, the structure in the paper doesn't meet"Don't damage in the tremor"; Different lateral load patterns considerably affect the results of the static Push-Over analysis; Finally, the reduced steel beam section makes it easier for plastic hinges to be formed in the reduced places instead of columns; Strong columns and weak beams greatly improve seismic behaviors of the structure.