Experimental investigation on seismic performance of steel frame-bent structures with braces in thermal power plants
Xu Jimin1,2 Gao Xiangyu1 Xi Haobo1 Liu Chao3 Wang Yongqiang4 Zhang Lingwei4
1. Beijing Key Lab of Earthquake Engineering and Structural Retrofit, Beijing University of Technology, Beijing 100124, China;
2. Central Research Institute of Building and Construction Co., Ltd., Beijing 100088, China;
3. Beijing Electric Power Engineering Company, Beijing 100070, China;
4. North China Electric Power Design Institute Co., Ltd., Beijing 100120, China
Abstract：Low cyclic loading tests with lateral restraint were carried out using a 1∶10 scale model to investigate the seismic performance of the steel frame-bent structures with braces in domestic large-capacity and thermal power plants. The transverse roof trusses from the main building of a thermal power plant are utilized as the research object. The seismic performance is evaluated according to the observed experimental phenomena and the obtained hysterics loops, skeleton curves, stiffness degradation curves, ductility index, and the effective viscous damping coefficient. The research results show that the steel frame-bent structure with braces has good seismic performance, with a plump load-displacement curve as well as good ductility and energy dissipation capacity. The initial structural failure first appeared in the bottom-bracing part and the sequence of articulation development moved from the hinge beam to the hinge column. The failure mode of the frame-structuring columns was compression bending deformation, while the bent-structuring showed flexural-torsional deformation. The maximum bearing capacity in the positive loading was approximately 11.3%higher than that in the negative loading by under unidirectional loading within the frame plane, so the seismic performance was asymmetric. The weak story should be strengthened in the design because the inter-story drift angle of the second floor reaches 1/22. The buckling of braces is the main reason for the out-of-plane distortion, joint deformation, and the residual deformation.
