LOAD RESISTANCE AND HYSTERETIC RESPONSE OF BRBS CONFINED ADDITIONALLY BY SHUTTLE-SHAPED TRUSSES
Bo-Li Zhu 1*, Yan-Lin Guo1 and Peng Zhou1
1 Department of Civil Engineering, Tsinghua University, Beijing 100084, China
This paper presents a Shuttle-Shaped Truss-Confined Buckling-Restrained Brace (SSTC-BRB) and investigates its in-plane elastic buckling, load resistance and hysteretic responses. The SSTC-BRB is simply composed of a single steel tube core and several shuttle-shaped trusses sharing a single external restraining tube. It has not only aesthetical appearance, but also high axial load-carrying efficiency, thus leading to an economical design. The elastic buckling performance of the SSTC-BRB is investigated, indicating that there exist two possible elastic buckling modes, namely symmetric and anti-symmetric buckling modes. Consequently the load resistance of SSTC-BRBs under monotonic axial compression is analyzed numerically and a lower limit of restraining ratio of SSTC-BRBs as a load-carrying type is recommended, where the cross-section of the core becomes fully yielded and reaches a plastic strain of 0.02 without global buckling of the SSTC-BRB. At last, the hysteretic performance of SSPTC-BRBs subjected to repeated axially compressive-tensile cyclic loads is studied numerically, and the corresponding lower limit of restraining ratio of SSPTC-BRBs is proposed as an energy-dissipation type.
Buckling-restrained braces; Shuttle-shaped; Truss-confined; Load-carrying capacity; Hysteretic response.