Study On Seismic Capacity And Sideways Collapse Of Frames With Buckling Restrained Braces

The great loss of human life and property in all previous earthquakes is mainly caused by the collapse of the building,and reasonable evaluation of the anti collapse ability of the building structure is a hot spot in the present study.Meanwhile,the research focus is Energy Dissipation earthquake engineering technology.This paper on the concrete frame structure increase of buckling restrained brace to the study frame of anti seismic performance of buckling restrained brace structure and lateral collapsed,it has certain reference value for the frame structure design of high intensity zone.Based on the existing literature at home and abroad,the research work in the following aspects is mainly carried out by numerical simulation analysis.（1）Using GEN MIDAS to establish a three-dimensional model of a coffee plant production workshop of Yunnan,the seismic performance and dynamic response under earthquake of frame with BRB structure be analyzed using the mode-superposition response spectrum method and elastic plastic time history.By comparing the hysteresis loops of the period,the displacement,the displacement angle between the layers,the floor shear and the buckling restrained brace of the frame structure and frame with BRB structure,the results show that the stiffness of the structure be increased and the story drift be reduced under small earthquake fortification by BRB and the hysteretic curve is full,the energy consumption is good,and the seismic response is reduced in the case of rare earthquake.（2）Two failure modes of vertical and lateral collapse are distinguished,and the judgment criterion and evaluation index of seismic collapse are expounded in detail,which lays the foundation for the analysis of POA and IDA.（3）Using SAP2000 to build a eight story concrete frame structure and frame with BRB structure model,two structures were analyzed by POA,with the overall super coefficient and ductility coefficient as the evaluation index.The comparative analysis results show that the lateral ultimate bearing capacity of the frame structure is increased by 40%,and the ductility is increased by 15.9%.The plastic hinge of the frame buckling restrained brace is consistent with the yield mechanism and BRB acts as the first line of defense against the earthquake.（4）Using IDA analysis and seismic fragility,the relationship between the two structures of Sa（T₁）and the inter layer displacement angle is studied,and the IDA curves and the seismic fragility curves are obtained.In the same Sa（T₁）,the interlayer displacement angleof the frame is larger.In the same time,the collapse probability of frame structure is obviously larger than that of frame buckling support structure.（5）On the basis of seismic fragility analysis,collapse margin ratio CMR of frame and frame with BRB is researched.CMR of frame with BRB was 3.54,compared to 2.61 of the frame structure,improved by 35.6%.Buckling restrained brace has a certain contribution to the sideways collapse of the structure.