Configuration And Experimental Study On Buckling Restrained Braces With The Core Component Of Steel Bar

The buckling restrained brace is a kind of metal energy dissipator with stable hysteretic characteristic, which has been widely used in building structure, while the application of buckling restrained braces in reinforced concrete structure is more confined to the reinforcement of old buildings. The paper proposes a buckling restrained brace whose core component is steel bar, which can be made simply, cost lowly, and widely applied to cast-in-place reinforced concrete structure, based on the status quo of patent protection of intellectual property rights of buckling restrained braces and the relatively expensive processing production cost of most buckling restrained braces. The low cycle fatigue test on the new-type buckling restrained braces is carried out, and the finite element method is used to validate the result of the test. Main contents are as follows:Firstly, based on current status of the application of reinforced concrete structure in our country and the application of buckling restrained braces in reinforced concrete structure, the paper proposes the concept of putting steel bar with low yield into use in buckling restrained braces, and introduces in detail the value and configuration of the research of the new-type buckling restrained braces.Secondly, the paper conducts a series of configuration treatments on test specimens, including the processing of the end of core steel, the end configuration of specimens, the setting of compressed layers, and so on. And theoretical analysis of global stability and local stability of buckling restrained braces is also conducted. Additionally, the pull-out test to determine the bond strength of the core steel bar and concrete is carried out, which can provide necessary basis for configuration processing of the core steel in the test specimens.Thirdly, the test results of three specimens show stable and symmetric hysteric performance. The restraining component of the first specimen is the concrete-filled steel tube, while the other two’s is reinforced concrete. Compared to the first specimen, the second and the third one can play its full role of the compressed layer with the special design, which is much closer to practical application.Finally, the finite element model established by ABAQUS is simulated well with experiment results in multi-wave buckling of core steel and the contact state between the core steel and restraining component. The conclusion that the concrete in the loading process without damage is verified. The rationality of segmentation method of restraining component by compressed layer in practical application is also verified.