مرکز منطقه ای اطلاع رساني علوم و فناوري - Design, fabrication, and cyclic behavior of aluminum alloy core buckling restrained braces (BRBs)

Abstract :

Potential use of aluminum alloy core material as an alternative to steel in BRBs was investigated. Effectiveness/superiority of such braces that are designed, produced, and tested for the first time in this work, over the available types of BRBs is evaluated. Numerous tensile test specimens (coupons) were prepared in prototype samples according to the prescribed standards. Material test results contain valuable information for choosing the materials to be used in designing and fabricating the BRBs. A strain-gauge placement configuration was also suggested and tested in order to correctly measure the axial strains in the yielding portions of BRB cores. The reasons of why A5083-H111 aluminum alloy materials were preferred in the fabrication of BRB-AC1 and BRB- AC3 specimens were given in detail. Fabrication steps of aluminum alloy BRBs, welding procedures followed, assumed cyclic loading test protocol, instrumentation and data acquisition system used in the tests were described in the scope of this study. Experimentally obtained force-displacement hysteretic curves, tension and compression capacities, dissipated cumulative energies (𝐸ℎ), cumulative inelastic displacements (𝜂), and effective damping ratios (𝜉𝑒𝑓𝑓𝑏) were calculated and compared. The requirement indicating that tests must involve the highest compression adjustment factor (𝛽 1.3), ensuring the symmetrical hysteretic curves, was fulfilled. It is concluded that aluminum alloy BRBs (BRB-AC3) with weld-free end connections have superior behavioral values when compared to aluminum alloy BRBs with welded end connections (BRB-AC1).