Analytical investigation on the behavior of smart recentering T-stub components with superelastic shape memory alloy (SMA) bolts and performance-based optimal design

摘要

The partially-restrained (PR) bolted T-stub connections have been widely used in replacement of the established fully-restrained (FR) welded connections which are susceptible to sudden brittle Mure. These bolted T-stub connections can permit deformation easily exceeding the allowable limit without any fracture because they are constructed with design philosophy that plastic deformation concentrates on bolt fasteners made by ductile steel materials. Thus, the PR bolted connections take advantage of excellent energy dissipation capacity in their moment and rotation behavior. However, considerable amount of residual deformation may occur at the bolted connection subjected to excessive plastic deformation, thereby providing additional cost to recover to original configuratioa In this study, superelastic shape memory alloy (SMA) bolts which have the recentering capability upon unloading are intended to be fabricated so as to solve 1hese drawbacks, and utilized by replacing conventional steel bolts in the PR bolted T-stub connection. Instead of the full-scale T-stub connection under bending moment, simplified T-stub components subjected to axial force are designed on the basis of basic equilibrium theory that bending moment transferred from beam to column can be converted into equivalent couple forces acting on the beam flange. The feasible failure modes followed by corresponding response mechanisms are taken into consideration for component design with superelastic SMA bolts. The inelastic behaviors of such T-stub components under cyclic loading are simulated by advanced 3-dimensional (3D) finite element (FE) analyses. Finally, this study suggests optimal design for smart recentering T-stub components with respect to recentering and energy dissipation after observing the FE analysis results.