Seismic performance of self-centring connections with two energy dissipation stages for reusable modular steel buildings

Abstract

This paper presented a feasibility study on a self-centring connection with two energy dissipation stages for use as a combined inter-module and intra-module connection in reusable modular steel buildings. The proposed connection was equipped with shape memory alloy (SMA) disc washers and friction dampers, the former for self-centring and the latter for energy-dissipation functions. The design concept of two energy dissipation stages was to achieve structural longevity and member reuse by 1) enabling rapid recovery after small and medium earthquakes, and 2) facilitating prompt repair if at all needed after large earthquakes. A spring analytical model was proposed, wherein each connection component was symbolised as a rotational spring. Based on the model, a design methodology to meet the two-stage performance goals was derived, where the critical story drift ratio between the two stages was expressed as a function of the properties of friction dampers and SMA disc washers. Detailed finite element simulations were used to validate the proposed design concept and the spring model and to assess the influence of the friction dampers and SMA disc washers on the hysteresis behaviour of the connection. The results demonstrated that the proposed connection would facilitate the design objectives when designed based on the proposed spring model to ensure structural longevity, member reuse, and efficient recovery and repair after seismic events.