Resistance Definition for Membrane Retrofit Concrete Masonry Walls Subjected to Blast

Mitigation techniques are currently being sought to ensure public safety in the event of intentional or accidental explosions. Building material fragmentation is a major cause of human injury during such events. One of the most common methods of construction in buildings is the use of unreinforced, ungrouted, infill concrete masonry walls. Concrete masonry provides a fast inexpensive way to construct buildings of various heights; however, these walls are extremely vulnerable to blast pressure resulting in collapse, fragmentation, and severe injury to occupants. Much research has been conducted using full scale blast tests as well as high fidelity computational methods to study the behavior of membrane retrofit masonry walls, but the cost is prohibitive. Design tools developed by other investigators in the field have been available for the past few years; however, they lack a direct definition of the membrane retrofit and their accuracy remains questionable when compared to actual blast test data. The research presented in this paper developed resistance function definitions for three different scenarios of membrane retrofit unreinforced concrete masonry walls. These functions include the bonded and unbonded membrane retrofit scenarios as well as the arching behavior of the masonry wall. The resistance functions were further coupled with single degree of freedom systems to predict the wall response to blast loads. This research gives the structural engineer a practical tool for the design of membrane retrofit masonry walls to resist blast pressures.