Computational Investigations on the In-Plane Capacity of a URM Wall: Effect of Material Uncertainty

Preserving the aging unreinforced masonry (URM) building stock and architectural heritage requires accurate predictions regarding their structural performance under various loading conditions to provide sustainable conservation plans. Often, the considerable variation in material properties and uncertainties regarding the as-is condition of the existing buildings forces us to perform conservative and deterministic analysis using various computational modelling strategies targeting the lower bound capacity of the structural systems. With recent advances in computational power, different probabilistic structural analysis approaches have been presented, often considering loading and material uncertainties within the adopted computational modelling framework. However, experimental data to support simulations is insufficient, and several assumptions often must be made regarding the probability distributions and distribution parameters of the variables. It is rarely investigated how these assumptions affect the behaviour and maximum load-carrying capacity of the analyzed URM structure. To this end, this study proposes a probabilistic analysis framework using the discrete element method (DEM) to investigate the effects of modelling parameters and their probability distribution on the in-plane lateral force capacity of URM walls subjected to combined compression-shear loading. The effect of material uncertainties is addressed by performing a large number of simulations with different bond and brick strength properties explicitly represented in the adopted DEM-based modelling strategy. The results show that the impact of the probability distribution of the bond frictional resistance for the examined URM wall may not significantly influence its behaviour and capacity. The adopted framework can be used in the decision-making processes, preserving cultural heritage and avoiding expensive repair costs.