Shaking table test of concrete-filled steel tubular column-steel beam-light weight steel primary-secondary frame structures
In order to improve the application of light steel frame structures,based on the concept of primary-secondary structures,a building structure with concrete-filled steel tubular(CFST)column-steel beam-diagonal braces as the main structure forming the main lateral force resistance system,and light weight steel frame as the secondary structure bearing its own vertical load was proposed,and the secondary frame was combined with the main structure in a circular nesting manner.In order to study the influences of structural form of light weight steel frame,CFST column-steel beam connection joint and prefabricated floor of the secondary frame on the damage characteristics and seismic performance of primary-secondary frame structure,two 6-story scaled models with a scale ratio of 1∶3 were designed according to 7-degree 0.1g earthquake.Shaking table tests were conducted for the two models respectively to analyze their dynamic characteristics and seismic responses.The results show that the two scaled models have no obvious damage under 7-degree 0.lg rare earthquake,and the maximum inter-story drift ratio of the two models under 8-degree 0.2g extremely rare earthquake are 1/28 and 1/35,respectively.However,there is no obvious damage to the main structural members.The use of hinged beam-column joints for the secondary frame and the cancellation of steel columns in the third story can significantly reduce the impact of horizontal earthquakes on the secondary frame,improve the assembly rate and reduce cost.Rigid flange connection joints can ensure the first yield of CFST column ends under two-way horizontal earthquakes,which can meet the seismic requirements of connection joints.The prefabricated floor of the secondary frame strengthened by details and the side steel beams have obvious combined space effect,which can form an effective constraint on the twist of the side steel beams.