The Simulation Of Mechanical Properties And The Experiment Study For The Brb With Longitudinally Profiled Steel Plate As Its Inner Core

The buckling-restrained braces(BRB)is a kind of component to dissipate energy of structure with wide application which has many merits including stable properties,mature technology and low cost.Usually,this kind of brace consists of the inner-core and the restraining member mainly.There exists unbonded construction between them to make sure that the inner-core only takes axial load.However,with the deepening of the research there came to troubles such as uncontrollable yield position,local failure and poor fatigue performance.This paper researched a kind of BRB which has Longitudinal Profiled(LP)steel plate as it’s inner-core.The middle section will be weakened to make it succumb earlier than both sides to make the yield section controllable.An assembly method to strength the sides of BRB was proposed in this paper to reduce the effect of welding on the fatigue characteristics.For this type of BRB,the main research of contents and related conversations of this paper are as follows:(1)According to the principle of local instability,finding the relationship between maximum contact force with bucking mode of the inner-core,further,when the widththickness ratio less than 12.5,the inner-core will be buckled in both directions.Through the numerical simulation analysis,the regularity between half-wavelength calculation coefficient and width-thickness ratio of section is summarized.Concluded that the existence of variable thickness section was favorable for the local stability of the brace,and determined the effect of different types variable thickness segment for the contact forces.Finally,giving the calculation formula for designing constraint members.(2)According to the buckling mechanism of the braces,solving the variation range of the contact force of the variable thickness section,based on the calculation results via changing the thickness ratio,determining the limit load of the braces and giving the calculation formula which can be used for the calculation of brace designing.(3)Adopting an assembly way to fixing stiffening ribs without wields to reduce the negative effects caused by wielding,and making comparison test of two braces with one of the ribs was welded on the inner-core while the other was fixed on the inner-core by bolts.The test results show that the mechanical properties of the brace with LP steel plate as it’s inner-core are close to the calculated value,both of them have a full hysteresis curve,and the ability of deformation meets the requirements,reflecting excellent performance as braces.The comparison of those two also indicates that the connection mode of wield-free between ribs and inner-core could improves the fatigue performance of the brace effectively.The test results verify the feasibility of the BRB with LP steel plate as it’s inner-core and the way to assembly to fix ribs without wield.Finally,proposing several matters which are needed to be attention when designing braces combined in combination with the test results.