Numerical modelling of LSF truss floor-ceiling systems made of top hat sections

This study evaluates the accuracy of Finite Element (FE) models in simulating the structural behaviour of light steel framed (LSF) truss floor-ceiling systems made of top hat sections, focusing on three distinct modelling strategies. An advanced sheathed truss model was developed first, which represented the sheathing material, connections, imperfections, geometric and material nonlinearities, contact interaction behaviours and the connection between truss elements and truss and sheathing. This was followed by developing basic and improved unsheathed truss models. This study has quantitatively evaluated the capability of these models in simulating the failure loads and modes of seven tested LSF truss floor-ceiling specimens. The mechanical properties of the associated sheathing materials were also founded and incorporated into the FE models to improve their accuracy. This paper details the development of the advanced FE models of LSF truss floor-ceiling systems subjected to bending, and their results. The advanced sheathed model's predictions regarding failure modes, load capacities, and the relationships between load and mid-span deflection were analysed and compared with experimental results and also with those from other two unsheathed truss modelling strategies. A parametric study was also conducted using the validated advanced sheathed truss model by changing different parameters relevant to the LSF truss floor-ceiling systems. This paper also offers recommendations for modelling LSF truss floor-ceiling systems using appropriate FE techniques. • Conducted a numerical study of LSF truss floor-ceiling systems made of top hat sections. • Developed advanced finite element models of sheathed trusses and validated against experimental results. • Captured the complex behaviour and failure mechanisms of top hat trusses, including early failures of some members. • Developed computationally efficient unsheathed models and evaluated the suitability of improved unsheathed model. • Conducted a parametric study to determine the influence of many parameters on the structural performance of top hat trusses.