Structural Reliability Assessment of Safety Factors for Unreinforced Masonry Veneer Walls Subjected to Out-of-plane Loading

Structural safety can be enhanced by the reliability-based calibration of partial safety factors. This paper focuses on the structural reliability-based assessment of unreinforced masonry (URM) veneer wall system with flexible structural backing under uniformly distributed out-of-plane loadings. A stochastic computational model is developed which combines the Finite Element Analysis (FEA) and Monte Carlo simulation to study how the spatial variability of veneer wall material (masonry, wall tie, and timber) properties affects failure progression and system peak load (veneer capacity). Two scenarios, with and without wall tie offset, are considered, where wall tie offset represents the workmanship observed from laboratory testing. Probabilistic characterization of the veneer capacities for these scenarios under inward and outward out-of-plane loading is also reported. The model error statistics are combined with the probabilistic load models to determine the reliability index corresponding to the Australian Standard for Masonry Structures AS 3700. Annual reliabilities are compared to target reliabilities recommended by ISO 2394. It was found that existing levels of reliability exceed target reliabilities for most cases, and changes to the capacity reduction factor is also discussed.