Predicting the pull-through capacity of crest-fixed trapezoidal cladding with closely spaced ribs subject to localised dimpling and splitting failures

Crest-fixed trapezoidal cold-formed steel (CFS) cladding systems, widely used in Australia and neighbouring countries, are prone to localized pull-through failures around screw fasteners under high wind uplift/suction loading. Unlike corrugated cladding, which exhibits localized dimpling-type failures, and trapezoidal cladding with wide pans, which often fails through transverse splitting, trapezoidal cladding with closely spaced ribs can experience either localized dimpling or splitting-type pull-through failures. These failures result from significant stress concentrations beneath screw heads and the limited ductility of high-strength steel, posing challenges for accurate prediction through analytical methods. As a result, the design of crest-fixed trapezoidal cladding with closely spaced ribs relies on experimental testing, with few design guidelines available to address these specific failure modes and pull-through capacity. This study proposes and calibrates a ductile damage material model specifically for very thin, high-strength cold-formed steel, enabling accurate simulation of damage initiation, progression, and fracture. The model was implemented in an advanced finite element framework capable of reproducing both localized dimpling and transverse splitting pull-through failures under static wind uplift loading. Validation against experimental data showed excellent accuracy with a low coefficient of variation of 0.02, while an extensive parametric study identified the effects of key parameters such as crest height that increased the capacity by up to 90%. The findings improve the understanding of pull-through behaviour and lead to practical design recommendations for optimising crest-fixed trapezoidal cladding systems. The proposed equation predicted the capacities within 5%, demonstrating strong potential for design-code adoption.