Numerical Study on the Seismic Performance of CFST Modular Frame with Stainless Steel Connections

With the advancement of industrialization in the building industry, modular construction technology has emerged as a promising alternative to improve construction efficiency and reduce labor costs as well as operation duration in urban areas. Modular steel buildings have gained attention worldwide as the mainstream module products. It is known that the structural performance and workability of the inter-module connections in such buildings are essential to the life-cycle safety of the entire structure. Particularly in harsh environments prone to corrosion, such as coastal regions, the anti-corrosion resistance of intermodule connections poses a critical role in structural durability. In light of this, this study proposes a rotary-type inter-module connection made of stainless steel corner fittings and rotating connectors. Finite element analysis (FEA) modelling for an innovative corner-supported modular frame structure with concrete-filled steel tube (CFST) columns and steel beams assembled using this novel connection is established, with its effectiveness validated against experimental data. A comprehensive evaluation of the mechanical behavior of the structure under cyclic loading is then undertaken using the validated model. The seismic performance of the CFST frame with these stainless steel connections is examined in terms of the failure modes, the hysteresis curves, the ductility, and the energy dissipation capacity. The paper concludes with recommendations for the optimal design of such inter-module connections in seismic areas.