Reinforced masonry shear wall blast response limits for ASCE 59 and CSA S850

The current blast response limits for reinforced masonry (RM) walls in North American blast standards are based on parameters that neither account for the wall ductility capacities nor the influence of different design configurations on the wall damage tolerance levels. Specifically, ASCE (2011) and CSA (2012) currently assign a support chord rotation limit for each damage state (i.e., Superficial, Moderate, Heavy, and Hazardous) regardless of the different ductility capacities that structural components may possess when different design configurations are adopted. However, recent relevant studies demonstrated that wall configurations and their different design parameters significantly influence the out-of-plane performance of RM walls. For example, RM shear walls with boundary elements are considered a promising blast-resisting system due to their enhanced out-of-plane characteristics (e.g., strength and ductility) compared to those with typical cross-sections (i.e., rectangular). Nonetheless, the aforementioned standards do not assign separate design requirements or response limits for this new system due to the limited number of relevant studies available when such standards were being developed. To address this knowledge gap, the current study evaluates the blast behavior of such walls with different configurations and subsequently proposes new related blast response limits for ASCE 59 and CSA S850. An OpenSees model was developed and then validated through the results of several previous test programs under quasi-static and blast loads. Subsequently, the new response limits were generated using the model and compared to those currently available (i.e., ASCE 59-11/CSA S850-12) using pressure-impulse diagrams. Finally, the blast response of several RM walls with different configurations was evaluated when such walls were subjected to different blast demands. The results highlight the blast-resistance enhancements that boundary elements can provide to RM shear walls at different damage states and the need to develop category-specific blast response limit within blast design standards.