Concrete Masonry Unit Walls Retrofitted With Elastomeric Systems For Blast Loads

Concrete masonry units (CMU), commonly referred to as concrete blocks, are the most common construction material utilized throughout the United States and the world for exterior walls of conventional structures. While masonry provides adequate strength for conventional design loads, it does not meet the minimum design standards mandated for blast protection of new and renovated government facilities. One of the most dangerous aspects of blast response is debris hazard, defined as high-velocity fragments originating from walls, windows, light fixtures, equipment, and furniture. Retrofits for conventional structures have evolved over the years from blast hardening through the addition of mass using concrete or steel, to the application of lighter, more resilient and ductile materials. Research at ERDC has focused on the use of elastomeric materials to mitigate debris hazards resulting from blast events. A series of sub-scale and full-scale experiments was conducted by ERDC to investigate the potential benefit of elastomeric retrofit systems when applied to hollow, unreinforced, CMU walls subjected to an explosive event. This study discusses both the 1/4-scale static and dynamic experiments and the full-scale dynamic CMU wall experiments conducted over the past few years. The CMU wall response to static loading was characterized by resistance functions, and normalized pressure and impulse diagrams were used to characterize the dynamic loading.