Simulation of sheathed cold-formed steel shear walls under lateral load

In recent years, new innovative systems have emerged to ensure high structural and environmental performance. Among others, modular cold formed steel (CFS) framed construction has been widely adopted and used in modern, lightweight and cost-efficient engineering practice. The primary objective of this study is to simulate the behaviour of CFS framed shear walls sheathed with oriented strand board (OSB) subjected to monotonic lateral loading (i.e., wind) by means of high-fidelity continuum finite-element (CFE) analyses. A robust three dimensional shell CFE modelling protocol has been developed which aims to provide a benchmark modelling approach able to accurately capture strength, stiffness and failure mechanisms in the above-mentioned structural system. Particular attention was given to the modelling of the sheathing-toframe screw fasteners where their behaviour were experimentally derived. The proposed modelling protocol has been validated using experimental test results available in the literature, where a good agreement has been achieved. Subsequently, the effect of additional details which are commonly adopted in practice and go beyond the scope of available design guidelines, has been assessed. This includes: (a) the presence of two ledgers (i.e., rim tracks) on the interior face of the shear walls, (b) sheathing boards having different sizes from the overall shear wall sizes and thus the presence of both vertical and horizontal panel seams in the walls and (c) use of cement particle (CP) board at the bottom part of the shear wall, has been carried out. The key parameters which have most affected the lateral behaviour were identified. The developed modelling protocol is intended to provide an accurate experimentally-derived fastener-based computational tool of sheathed CFS shear walls that can extend the current design codes.