Behaviour and design of concrete-filled steel plate composite walls in fire

The increasing demand for structural systems that offer speed, efficiency, and resilience in high-rise and modular construction has led to the growing adoption of concrete-filled steel plate composite (CFSPC) walls, which provide faster construction, reduced section sizes, and enhanced load-bearing capacity compared to reinforced concrete (RC) walls. Although the structural behaviour of CFSPC walls has been widely studied, fire design guidance for these systems remains limited. This study investigates the thermal–structural behaviour of CFSPC walls at elevated temperatures using a sequentially coupled approach implemented in Abaqus. The finite-element framework was first validated against published fire test data and then employed to simulate the fire performance of CFSPC walls through 110 models across a range of wall thicknesses, reinforcement axis distances, load ratios, fire exposures, and concrete and steel strengths. Based on the simulation results, the study develops design equations and design tables to be included in AS/NZS2327 standard to facilitate the fire design of CFSPC walls incorporating normal- and high-strength concrete and steel. The findings demonstrate that CFSPC walls exhibit superior fire performance compared to RC walls. This paper provides a code-compliant design approach to ensure the fire safety of CFSPC walls.