Fragment velocity response of grouted and unreinforced concrete masonry walls subjected to blast loading

Abstract

Very few methods are available for predicting the secondary fragment velocity and secondary fragment production of grouted and unreinforced concrete masonry unit (FGUR CMU) walls when subjected to blast loading. A novel energy-based methodology is developed that calculates the secondary fragment velocity of an unreinforced fully grouted concrete masonry unit (CMU) wall under blast loading. The computationally efficient, engineering-level methodology was originally derived for fragment velocity calculation of unreinforced ungrouted CMU walls. Existing approaches often require large computational resources or fail to predict secondary fragment velocity accurately; this approach calculates fragment velocities with minimal computational effort. The applicability of this analytical model to unreinforced fully grouted CMU walls is discussed. The selection of a resistance function and assumptions about fragment behavior are examined. Velocity calculations throughout wall fragmentation are compared to velocities from quarter-scale and full-scale experiments and reasonable agreement is observed.