Comparative study on seismic performance of aluminium, carbon steel and stainless steel moment-resisting frame buildings

Aluminium’s unique properties make it a competitive alternative to carbon steel and stainless steel, particularly for lightweight structures. While past research has demonstrated the structural efficiency of aluminium components and low-rise frame buildings under monotonic loading, research on seismic performance of aluminium frame buildings remains scarce. To further investigate aluminium’s capability to withstand seismic hazards, this study numerically evaluates, for the first time, the seismic performance of low- to high-rise aluminium moment-resisting frame (MRF) buildings and compares them with equivalent buildings made from conventional carbon steel and stainless steel. Particularly, four carbon steel MRF buildings with 2, 4, 6, and 8 storeys, taken from the literature, are used as benchmarks to design equivalent aluminium and stainless steel buildings. Nonlinear pushover analyses are performed using the OpenSees framework, considering different lateral force profiles. The capacity curves are obtained and compared. Moreover, damage measure (DM) limit states are proposed, for the first time, for aluminium and stainless steel MRF buildings, necessary for evaluating fragility. Incremental dynamic analyses (IDAs) are carried out, accounting for earthquake record-to-record variability, to generate data of ground motion intensity measure, and global and local engineering demand parameters (EDPs). Subsequently, the IDA data along with the DM limit states are utilised to derive fragility curves based on global and local EDPs. Overall, the findings of this study highlight aluminium as not only a structurally efficient and sustainable alternative, but also as a resilient material solution for seismic-resistant design in modern framed buildings.