Development of self-centring beam-to-column joints with large-dimensional SMA buckling-restrained plates

This paper presents an innovative self-centring (SC) beam-to-column joint (BCJ) design that utilises shape memory alloy (SMA) plates. The proposed SMA-SC-BCJ is constructed through a straightforward approach using large-scale SMA plates to concentrate inelastic deformation and achieve SC capability. This paper first introduces the components and configuration of SMA-SC-BCJ, followed by the development of a refined finite element model for simulations. Validation against previous experiments verifies the model accuracy in capturing joint behaviour. The analysis shows SMA-SC-BCJ exhibits desirable flag-shaped hysteretic behaviours with excellent SC capability, achieving approximately 92 % recovery alongside moderate energy dissipation. Substantial inelastic deformation localises in the SMA fuse plate due to joint rocking, with minimal plastic strain around the rocking centre. Parametric studies on shear element construction, bolt pretension levels and beam gap distances provide additional insights into the joint design. The proposed design meets the objectives for a minimal-damage beam-to-column joint with simple construction. The SMA-SC-BCJ design recommendations are presented on the basis of performance assessments, elucidating the effectiveness of the system. This work contributes an innovative seismic-resistant joint solution that advances the emerging practices towards resilient structures.