Concrete Masonry Unit Wall and Retrofit Analysis Using Simplified Methods

Abstract

Concrete Masonry Unit (CMU) wall construction is prevalent throughout the United States and the world. While masonry provides adequate strength for conventional design loads, in many circumstances it is inadequate for meeting the minimum standards mandated for blast protection of new and renovated government construction. Protection of military and civilian occupants of masonry structures has received long needed research, due to increased terrorist threat and government mandates for new construction and renovation of federal buildings. The US Army Engineer Research and Development Center (ERDC) has been involved in blast resistant structures research for decades. In the last ten years analytic approaches developed for hardened structures were adapted to terrorist bombings of conventional construction. In addition, simplified response surface based methods, developed to access damage from accidental explosions, were employed to develop models for terrorist bomb attack. These pressure-impulse (P-I) methods were derived from limited data sets and single-degree-of-freedom analytic models. Retrofits to mitigate blast hazard to occupants of masonry structures have been the focus of recent ERDC research. This research resulted in economical retrofits to reduce debris hazard for occupants rather than to blast-harden the masonry structures. This paper summarizes the development and use of simplified models for the analysis and design of CMU walls and the experimental programs used for model validation.