Study on seismic reduction of CFST column-pinned steel beam-RC core tube structures
A series of issues,caused by the welding of traditional dual lateral force resisting system,can be effectively solved by CFST(concrete-filled steel tube)column-pinned steel beam-RC(reinforced concrete)core tube structure,however,new problem would be generated that it unavoidably affects the seismic performance of the structure.Therefore,there is an urgent need for research on energy dissipation and seismic mitigation specific to this type of structure.This paper focuses on a 30-story CFST column-pinned steel beam-RC core tube structure.By introducing damping layers with different construction forms to form energy dissipation mechanisms,the seismic performance of the structure is investigated.Elastic-plastic time history analysis is conducted using the OpenSees finite element software.The optimal structural form of the damping layer was evaluated and determined,and which is adopted to investigate the seismic reduction performance of the structure under rare earthquakes with one and two damping layers,as well as the influence on the seismic performance of the one-damping-layer structure with variable damping coefficient and velocity exponent of the viscous damper.The results show that damping layer in the form of vertical inclined bracing exhibited the best control effect on the structure's top displacement,inter-story drift ratio,and base shear,while also demonstrating superior energy dissipation capabilities.The comprehensive performance of structures with the two damping layers is slightly better than that of the one damping layer,while structures with the one damping layer is more sensitive to the variation of the location of the damping layer,and the seismic reduction of structures is the best when the damping layer is located at 1/3 height of the structure.Moreover,excessively large or small damping coefficients and velocity exponent would have adverse effects on the structure,and the velocity exponent could effectively reduce the drift ratio of the structure.However,more attention should be given to potential issues such as sudden displacement changes and increased base shear force.
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