The steady recurrence of blast events involving civilian buildings constitutes an ever challenge for structural engineers worldwide. Design methodologies addressing the blast resistance of masonry buildings are mostly grounded in deterministic approaches, which neglect several sources of uncertainty affecting the structural response—including variability in material properties, geometry, and accuracy of predictive numerical models. A risk-based decision making process provides the most rigorous and comprehensive approach to the structural design of civilian buildings subjected to blast loading. Such a design methodology is used to quantify risk as the outcome of the statistical uncertainties associated with the load parameters, structural response, and blast hazard. The steel bar uniaxial stress-strain relationship is assumed to be bilinear, and the enhanced yield stress and tensile strength under dynamic loading are obtained by adopting the strain rate dependent model proposed by Malvar.