Research On The Energy Dissipation Of New All-steel Buckling Restrained Brace

Buckling Restrained Brace(BRB)is a new energy dissipation component,Usually consists of kernel core and peripheral constraint components,the kernel core is mostly made of steel with low yield points,the axial load directly acts on the kernel core,and the peripheral constraint components only restrict the kernel core,improving the buckling load of the kernel core and make the whole section reach the yield.The lateral stiffness of the frame structure is smaller,lateral displacement of the structure is lager under the strong earthquake or wind loads,so the Buckling Restrained Brace is mainly used in the frame structure as the lateral force-resisting member to improve the lateral stiffness of the frame structure.It is common for Buckling-restrained braces using concrete filled steel tube,but it needs to be wrapped with unbonding layers of the kernel core and leave an appropriate gap,so the production is difficult and time-consuming.Manufacturing of the all-steel BRBs is more easier than the CFST-BRBs,but the common form of the BRBs' s section is a single core section,and the connection between single core section and the nodal plate of the frame is more complicated,and the peripheral constraint components mostly adopt integral type or welding.Based on the above analysis,this paper puts forward a novel type of double T-section steel assembly Buckling Restrained Brace,the kernel core adopts double section to clamp the nodal plate of the frame and reduce the connection length;the peripheral constraint components corresponds to select the china's section steel and adopt the high strength bolt assembly,it is suitable for industrial mass production and site installation and maintenance.The research method of this paper is theoretical analysis combined with finite element numerical simulation to analyze the seismic performance of this new type of Buckling Restrained Brace structure system.The specific contents are as follows:(1)In this paper,the theoretical analysis of the Buckling Restrained Brace with double-T is carried out,the limit value of the constraint ratio and width-to-thickness ratio are deduced through the overall stability analysis and local stability analysis,reasonable gap value is obtained for the deformation analysis of the kernel core.(2)Finite element software ABAQUS is used to analyze the finite element numerical simulation of the Buckling Restrained Brace with double-T and the parameters affecting the performance of the Buckling Restrained Brace;respectivelyanalyzing and studying the clearance between the kernel core and the peripheral constraint component,the constraint ratio,the width-to-thickness ratio of the kernel core and the bolt-space on the performance of the Buckling Restrained Brace,obtained the reasonable parameter range.Under the same conditions,comparing and analyzing the performance of the hysteretic energy dissipation between the Buckling Restrained Brace and common brace.(3)According to the above analysis and research,the use of programming software OpenSees further study the seismic performance of the Buckling Restrained Brace in the composite structure system,and compared with the pure frame structure system and common brace frame structure system,extracted from the hysteretic performance of skeleton curve in the third chapter and assigned to the Buckling Restrained Brace of the composite structure system.The layer shear force,story drift and vertex lateral displacement of three structural systems are analyzed and compared,discover this kind of Buckling Restrained Brace with double-T has good earthquake mitigation and energy dissipation capacity effect.