# Damage Analysis and Evaluation of Light Steel Structures Exposed to Wind Hazards
## 2 Cladding  
Profiled steel cladding is widely used in both roof and wall paneling. The cladding is fixed at its crest to battens or purlins beneath using self-tapping screws to prevent water ingress. The corrugated cladding is fixed at each alternate crest using a fastener comprising a self-tapping screw. Roofing of low-rise buildings (houses, warehouses, industrial sheds, etc.) are subjected to large temporally and spatially varying wind pressures during wind storms such as tropical cyclones. Theses fluctuating pressures are generated by turbulence in the approaching wind flow. The pressures on parts of the roof vary with the changes in wind speed and direction as a cyclone tracks past the building. Roof cladding with light gauge profiled metal sheeting are susceptible to low-cycle fatigue, as was seen in Darwin, Australia, after Cyclone Tracy in 1974, where more than 90% of houses and 70% of other structures suffered significant loss of roof cladding. Following Cyclone Larry, which impacted on Innisfail, Australia, in 2006, some cases of fatigue failure of metal cladding were also observed [5]. Figure 3: Mainframe collapsed during the typhoon event [6]. Figure 2: Buckling of Purlins under the wind uplift loadings. When subjected to strong sustained fluctuating wind uplift, the sheeting may fail locally in the vicinity of fasteners by cracking induced by fatigue [7; 8]. These cracks can be propagated to form a sizeable hole that allows the fastener to pull through the cladding sheet, potentially expediting the loss of entire cladding sheets. Loss of roofing sheets could then lead to the overloading of other structural elements, with the consequence often being the collapse of the entire building. As a first step to study the fatigue behavior of light gauge corrugated steel roofing under cyclic uplift wind loading, experimental and finite element analyses of roofing assemblies with different spans and fastening systems were conducted under static loading conditions. [PERSON] and [PERSON] [9] proposed the finite element method to study the collapse and local plastic behavior of trapezoidal profile sheeting under monotonic loads. The close agreement between finite element and test results validated the finite element model and open the way for a theoretical model of the failure behavior of roofing sheets. [PERSON] [10; 11; 12] proposed several test methods for profiled steel cladding system and conducted full size and small scale experiments, in which they investigated the influence of secondary elements, the thickness of plates, and yield limit, as well as the geometrical properties of the screw. They also described the behavior and the design of crest-fixed profiled steel roof claddings under wind uplift, and came to the conclusion of two different local failure modes: the dimpling of crests/pull-through failure at the fastener [10]. Research by [PERSON] and [PERSON] [13] concluded that the use of two-span specimens in the longitudinal direction with simple supports and one or two panels in the transverse direction were adequate when simulating real behavior, whether it is investigated in a laboratory or through analytical models. [PERSON] et al. [14] developed a numerical model that can simulate the static response of corrugated roof claddings. The model can be used to predict the response of cladding subject to design cyclone pressure trace, excluding fatigue effects, and demonstrates the potential of the model to investigate more complicated loading circumstances. [PERSON] [15; 16] proposed a finite element model that includes a splitting criterion and other advanced features (including geometric imperfections, buckling effects, contact modeling, and hyperelastic behavior of neoprene washers) that used a detailed parametric study to develop suitable design formulae for local failures. [PERSON] [17] investigated a testing approach for trapezoidal crest fastened metal claddings that may serve as a basis for testing research of the cladding systems.