Study On Seismic Performance Of A New Type Of Buckling Restrained Braces With Energy-Dissipating Steel Plate Elements

With the continuous development of anti-seismic technology and anti-seismic design concepts,the focus of anti-seismic design has gradually evolved from "collapse-resistant design" to "repairable design".On the basis of performance-based seismic fortification concepts,how to make buildings keep the ability to have good repair functions after experiencing earthquake became a new research hotspot,and the concept of "recoverable functional structure" came into being.However,the core material connected to the frame structure of the traditional buckling restrained braced frame is destroyed after the earthquake,and repairing the destroyed core plate is very difficult after the earthquake.Based on the design concept of "recoverable functional structure",this paper proposes a buckling restrained braces with replaceable energy-dissipating steel plate elements,and conducts experimental and theoretical research on its seismic performance.The main tasks include:(1)Introduce the proposed new buckling restrained braces with energy-dissipating steel plate elements,mainly including the advantages of this new buckling restrained braces,the composition of internal and external restraint members and energy-dissipating core plates,and how to assemble each component,etc.(2)Based on the repairable design concept,new buckling restrained braces Specimens A1-A6 were designed.The parameters mainly include the length,area and loading system of the restrained yield section of the energy-dissipating steel plate element.The 6 sets of full-scale specimens were tested.The hysteresis curve,skeleton curve,strength,stiffness,plastic deformation and cumulative energy dissipation capacity of the support are analyzed.Based on the test data,the recommended value of the strain strengthening coefficient and the calculation formula of the compressive strength adjustment coefficient of the braces are given,which provides a theoretical basis for the relevant design of braces.(3)The OpenSees finite element analysis software was used to carry out a numerical simulation study on the nonlinear behavior of the new buckling restrained braces.By assigning the modified Park-Ang material constitutive model to the Truss element,it can simulate the performance of energy-dissipating steel plate element under low-cycle reciprocating load well.(4)Through the dynamic time history analysis of the original frame and the new BRB Frame structure before and after the installation of the buckling restrained braces for the three-story and one-span central supporting frame structure,the influence of the buckling restrained braces on the damping effect of the frame structure is studied.The results show that the proposed new buckling restrained braces can effectively limit the interlayer deformation and residual deformation of the structure,especially under the action of large earthquakes,its effect is more significant.