SMA-based Self-centering Columns
Compared with other structural connections, column base connections have received relatively limited attention in research, so as to the self-centering behavior of them. Traditional moment resisting frames dissipate energy by forming plastic hinges at pre-defined locations. Fat hysteresis loops are expected, which means that a significant amount of energy can be dissipated. Compared with traditional moment resisting frames, the energy dissipation ability of SMA-based SC structure is relatively moderate (characterized by a flag-shaped hysteresis loop, the enclosed area is reduced). Therefore, external energy dissipation devices should be provided to supplement the energy dissipation of this structural system. This project is developed from the study in Wang et al. (2019) and discusses about proper energy dissipation methods to modify the performance of the novel self-centering column base connection (equipped steel angles).
Ref: Wang, B., Zhu, S., Qiu, C. X., & Jin, H. (2019). High-performance self-centering steel columns with shape memory alloy bolts: Design procedure and experimental evaluation. Engineering Structures, 182, 446-458.
Three models of SC column base connections were simulated using the finite element software ABAQUS. They were column base without steel angles, with 20mm width steel angles and with 30mm steel angles. From the numerical analysis result, the steel angles could assist in dissipating energy over the loading cycles and in the meantime, excellent SC performance could be achieved. The primary column was damage-free through the entire cyclic loading cycle. The result showed that there was a trade-off between the energy dissipation capability and the SC performance. Enhancing energy dissipation capability means enlarging the hysteresis loop, which somehow sacrifices the SC performance. In the practical design, the desired performance of the column base connection can be predicted and achieved by adjusting the width and thickness of equipped steel angles.
The experimental study of this column has also been completed and the result will be published soon.