Local plastic failure of light gauge steel roofing sheets: Finite element analysis versus experiment

Screw-fastened light gauge steel profiled roof sheeting, which is widely used in houses and other low-rise buildings, may fail locally in the vicinity of the screw fastener by plastic collapse under strong peak wind loads or by cracking due to low cycle fatigue under sustained fluctuating wind loads, resulting in the sheeting being pulled over the fastener. Loss of roofing sheets can then lead to overloading of other structural elements, with the consequence often being the collapse of the entire building. Several experimental studies have been carried out on the local plastic failure and fatigue strength of roofing sheets, but the problem has been subjected to only limited rigorous theoretical analysis. This paper therefore presents a study on the finite element modelling of the collapse behaviour of trapezoidal profile sheeting under monotonic loads. Elastic-plastic large deflection finite element analyses using the Semi-Loof shell element are carried out and the results compared with those from carefully conducted experiments. The close agreement between the finite element and test results validates the finite element model. The success of the finite element model opens the way for theoretical modelling of the failure behaviour of roofing sheets, the optimal design of sheeting profiles, and for future work on cyclone-induced fatigue of roofing sheets which requires a detailed examination of stresses and strains in the vicinity of fastener holes.