Seismic Performance Research On New Steel Frame And Concrete Core-Tube Mixed Structure

The steel frame mainly resists vertical load, whereas the concrete core-tube mainly resists lateral load in the high-rise steel frame concrete core-tube mixed structure. The steel frame have the advantages of lighter weight, longer span and better ductility compared with concrete structure in the high-rise mixed structure; Meanwhile the concrete core-tube have the advantages of lower costs and stronger stiffness, as the results, the high-rise mixed structures have been largely promoted and widespread applied. While the high-rise mixed structure has its disadvantages, such as the steel frame owns low efficiency for lateral load, the core-tube can’t be good cooperative work with steel frames, the beam-column joints have the characteristic of poor ductility, and it is hard to repair after earthquake. This Paper put forward a new high-rise mixed structure called the buckling restrained brace self-centering connection steel frame and concrete core-tube mixed structure. This new mixed structure can increase the efficiency for resisting lateral load, improve the characteristic of cooperative work between steel frame and concrete core-tube, solve the problem of poor ductility at the beam-column joints, and decrease the residual deformation. Meanwhile the braces and angles in self-centering connections are easily replaced after earthquake, so it can largely decrease the economic losses. This Paper studied as follows:(1)Put forward a multi-liner model of restoring force of self-centering connection, and use the equivalent linearization method calculating the elastic-plastic lateral deformation of the structure. Studies show that simplicity method is convenient to use, and it can satisfy the accuracy demands in practical engineering.(2)This paper made a parameter analysis on 45 structure models which have the same elastic lateral stiffness to research the influence for different relative stiffness models on the peak story displacement。The elastic-plastic time-history analysis is carried out for the new mixed structure to evaluate the seismic performance of the structure.(3)This Paper make a comparison analysis between mixed structure with selfcentering connections and mixed structure with rigid connections. The results show that the mixed structure with self-centering connections has better seismic proformance than the mixed structure with rigid connections, A preliminary cost analysis shows that the fabrication and erection cost of a self-centering connections is competitive with the same mixed structure with rigid connections. Repair costs following an earthquake are relatively inexpensive, since inelastic deformations are confined to the angles.