Fatigue Performance of Screw-Fastened Light-Gauge-Steel Roofing Sheets

Abstract

When subjected to strong sustained fluctuating wind uplift, screw-fastened light-gauge-steel profiled roofing sheets may fail locally in the vicinity of fasteners by cracking due to fatigue, resulting in the sheeting being pulled free of the fastener. A series of fatigue tests was performed on three types of commonly used profiled roofing sheets to investigate their fatigue performance and profile effects under both constant-amplitude repeated loads and simulated uplifting wind loads. The sheeting profiles considered were arctangent, trapezoidal, and ribbed, and an alternate (or equivalent alternate) sheeting crest-fastening system was adopted. It was found that the fatigue performance of roofing sheets greatly depends on their profiles. The fatigue resistance of the arctangent type of sheeting to low-amplitude repeated loads was found to be higher than those of the other two types of roofing sheets. However, the situation is reversed under high-amplitude repeated loads. The linear and bilinear S - N curves on a log-log plot were used, respectively, to fit the experimental data, and the Goodman method was employed to approximately account for the effect of mean load. Load-sequence effects and the application of Miner's rule to the fatigue-life prediction of screw-fastened profiled roofing sheets under simulated wind loads were also investigated.