Evaluating the seismic performance of mid-rise composite modular buildings in low-to-moderate seismicity regions

Modular construction is the off-site fabrication and assembly of building components in a controlled factory environment, offering advantages in terms of time efficiency, quality control, and addressing labour shortages over traditional construction methods. While several studies have evaluated the seismic performance of steel modular buildings, limited studies have evaluated the seismic performance of composite modular buildings (CMBs) that incorporate composite elements, such as concrete-filled steel tubes (CFSTs). Moreover, the promising findings from steel modular buildings highlight the need to evaluate the seismic performance of CMBs, as this would facilitate the expansion of current design Standards to include modular construction. This study investigates the seismic performance of a 10-storey CMB with CFST columns. The methodology included developing a 3D finite element model in OpenSees software using advanced material models and modelling approaches to accurately simulate the nonlinear response. Modal analysis, nonlinear pushover analysis, and nonlinear time history analyses using a selected suite of ground motions were performed. Results indicated that Australian Standards underestimate the fundamental period, ductility, and overstrength of CMBs. The structure demonstrated robust performance, with generally low residual inter-storey drifts, suggesting minimal permanent deformation. The promising seismic performance of mid-rise CMBs with CFST columns in low-to-moderate seismicity suggests their potential safe application in high seismicity regions. • A novel joining method was used for composite modular buildings under earthquake. • Seismic performance of buildings is investigated using OpenSees software. • The joining method can be safely used for modular buildings under earthquake.