Applied Research In Multi-storey Steel Frame Of Buckling-Restrained Braces

Traditional braces in steel frame structures can not undergo a strong earthquake because of the happening of buckling, which is of disadvantage to energy dissipation of the structure in earthquake, and this will also weaken the capacity of the structure's seismic resistance. In order to improve the buckling performance of the braces, make no buckling of brace will take place in earthquake occurrence, as to traditional braced frame put forward a new system can avoid brace buckling, called buckling restrained braced frame(BRBF). This system is a large amount of adopt already in Japan and U.S.A., demonstrates a good anti-seismic performance.First, from the conceptual design, the quantity and reasonable arrangement form of braces in structure can be obtained. BRB takes one kind of braces to consume energy, its arrangement way has its special request inevitably. In this paper, analysis the nonlinear dynamic time interval response result of different arrangement way of the BRB in steel frame structure, has obtained several conclusions which arranged in the portal frame construction.Next, take the energy theory and the structure damage performance as the rationale, the nonlinear dynamic time interval analysis is carried on by using finite element software ANSYS, obtains damage quantity which structure each story produces, then determination portal frame construction damage quantity along each story distributed rule.The performance of BRB should adapt with the goal frame can display it to consume energy fully the absorption of shock function. This paper decides the portal frame construction is an object, has studied the BRB's performance parameter. Based on this, has established the computation model of the BRB's damage quantity, and has inferred the numerical calculus method of the BRB's damage quantity. Based on supposition which the goal displacement along each story is the same, has inferred the BRB's cross sectional area and the BRB damage quantity correlational dependence, then may determine distributed rule of each BRB's cross sectional area along each story. Finally, the nonlinear dynamic time interval analysis of BRBF is carried out by using ANSYS. In order to achieve ideally effect of consumes energy and absorption of shock, the key is determines the ratio of BRB's rigidity and the rigidity of the frame part. Based on the principle of 1 working in frame, this paper has inferred the reasonable value scope of the nominal rigidity Rs. Regarding nominal rigidity ratio which assigns, may determine structure each story should arrange BRB's specification. Will determine BRB arrangement in structure, thus forms the BRBF construction system's anatomic model. Regarding this BRBF carries on the nonlinear dynamic time interval analysis, may achieve each story's displacement, speed and acceleration time interval curve of BRBF structure system. Under the contrast earthquake function of the BRBF structure with stress performance of the pure frame part which its corresponds, discussed the buffer action which BRB to the structure, and has confirmed the BRB's quantity and the arrangement form rationality determined.