Seismic Performance Analysis Of Center Support Structure Of Beam - Wall Steel Frame

Compared with reinforced concrete structure, steel structure has better seismic behavior, however, due to the weakness of nodes and rods’ stability problem, after several times seismic damage investigation, we come to a conclusion that there exist two reasons in terms of the damages of steel frame or frame supporting structure:the first reason is that fracture failure easily occurred at nodes between beams and columns because of seismic action. the other one is lateral buckling easily occurred at center studdles under seismic action. Especially, shear capacity of storey and lateral stiffness will decrease sharply, and then story displacement will increase excessively when structure stress remains elastic-plastic range under reciprocating seismic action. Finally, this may result in the whole structure unstability. According to the failure situation, at present, there are two kinds of design ideas:1. improve the stress form of nodes, so as to prevent the brittle failure of joints between beams and columns;2. adopt buckling-restrained brace or eccentrically braced in steel frame supporting rods design.Given high construction cost and technology difficulty of buckling-restrained center brace or eccentrically braced, in this contribution, we adopts web opening steel frame concentrically braced system. The plastic hinge of the nodes are moved outward under seismic action. This benefits the avoid of the premature of supported rods of steel frame bracing system buckling as well as prevention of nodes from damage. Therefore, this contribution adopts web opening steel frame concentrically braced system to conduct seismic performance analysis and its contents as follows:(1) ABAQUS was used to establish three-dimensional finite element node model, at the same time, put low cyclic loading on main beam endpoint, and then the seismic performance of the structure is obtained via the node bearing capacity, stress displacement and hysteresis curves.(2) On the ground of actual case, SAP2000was utilized to establish web opening steel frame center support system model (inverted V). Applying seismic waves to the structure, through nonlinear time-history analysis and Pushover analysis, the impact of the beam web opening and ordinary steel frame center support system on structure seismic performance is comparatively analyzed.(3) Using SAP2000to establish web opening and ordinary steel frame supporting system, with different flange width-to-thickness, shear span and column slenderness ratio, model and obtained structural seismic performance influential factors of the three through natural vibration period and frequency, seismic energy curve, structure story shift, displacement angle internal force changing situation of brace and comparative analysis of their formation law of plastic hinge.