Design Method And Experiments Of Buckling-Restrained Brace With Isolation Steel Tube

Despite its simple manufacturing process and short processing cycle, all steel Buckling-Restrained Brace faces a big problem in global stability due to the limitation in design of cross section. Having a bigger cross section, concrete-filled steel tube Buckling-Restrained Brace offers a larger stiffness to be used as a long brace. However, its performance is hard to guarantee, since the gap between outsourcing constraint components and core can hardly be well controlled, damages may take place in viscoelastic material, direct contact between concrete and core often make concrete crushed, and a large fraction often shows up inside the brace. In this thesis, a Buckling-Restrained Brace with isolation steel tube is proposed to solve the problems above. A Buckling-Restrained Brace is mainly made up of two parts, a steel core and outsourcing constraint components. Outsourcing constraint components consist of an isolation steel tube, an outsourcing steel tube and concrete. The solation steel tube is installed to control the gap between outsourcing constraint components and core. Moreover, an isolation is created by the solation steel tube to prevent concrete from crush and decrease the fraction. Combining the advantages of all steel Buckling-Restrained Brace and Concrete-filled steel tube Buckling-Restrained Brace, the Buckling-Restrained Brace with isolation steel tube owns a more reasonable structure and offers a better performance. In this thesis, design procedures for this brace are proposed. The structure and performance are also analyzed by both pseudo-static hysteretic experiment and finite element simulation. The contents are as follows:1) On the basis of summarizing previous theoretical research on BRB, design procedures of the BRB with isolation steel tube are studied, including global stability, local stability, local stability of the core, width of the gap, and fatigue property of the core.2) Full scale pseudo-static hysteretic experiment of BRB with both plate core and cross core are carried out respectively. The plump hysteretic loops prove that the BRB with isolation steel tube has an excellent ductibility and energy dissipation. In addition, the structure of the BRB is simple and reasonable. All results shows great practical value in BRB with isolation steel tube.3) Parameter analysis is carried out by finite element simulation by ABAQUS. Results shows great influences on performance of BRB from width of the gap, fraction, and restraining ratio, providing a great guidance in BRB design and its application. 4) Contraposing the engineering design of BRB, the construction of BRB with plate core and cross core has been optimized, and then the H-section core has been proposed. Introduced the engineering design method and gave some suggestions for manufacture of BRB.