Experimental and probabilistic analysis of masonry cavity wall ties under out-of-plane loading with application of stochastic numerical analyses

Most existing studies on wall tie material characterisation are deterministic, and the random variability of tie behaviour which arises from the tie material, mortar quality and tie installation process were not studied extensively. This study presents the results of a probabilistic characterisation of corrugated-end cavity wall ties and a spatially variable stochastic finite element analysis of one-storey cavity wall subjected to out-of-plane loading, considering variable properties for the wall ties and masonry. The tie strengths were first tested according to AS2699.1:2020, resulting in an idealised load–displacement curve capable of describing the compressive and tensile behaviour of the tie. Suitable predictive models for the characteristic points of the idealised curve were determined by considering the goodness-of-fit of a range of probabilistic distributions, allowing the random variations in the derived cavity wall tie constitutive model to be considered. The numerical results indicated that inward loading was governed by tie failure, whereas outward loading was governed by masonry tensile cracking. Further spatial stochastic simulations indicated that the mean peak load under inward loading was 2.6% lower than the deterministic baseline of 5.46 kPa, with a COV of 0.06. While the mean peak load under outward loading was 1.4% higher than the deterministic baseline of 4.96 kPa, with a COV of 0.04. The findings provide novel insights into the development of probabilistic tie constitutive model, the interaction of spatially variable components in cavity wall systems and the subtle difference in load-sharing mechanisms under different out-of-plane loading conditions, with implications for further reliability assessment and design safety. • Experimental characterisation of cavity wall ties under compression and tension. • Cavity wall tie variability was quantified to form a probabilistic material model. • Failure mode of inward loading case was governed by tie properties. • Failure mode of outward loading case was governed by masonry properties. • Subtle differences were observed between stochastic and deterministic results.