SPALL DAMAGE TO CONCRETE WALLS FROM CLOSE-IN CASED AND UNCASED EXPLOSIONS IN AIR

In recent years, industrial concerns for safety and protection against high-explosive loadings have increased Industries that manufacture ex plosive devices or use processes with the potential for explosions use concrete barricades to protect workers from exposure to accidental bl ast and fragmentation. Other industries we concrete barricades as prot ection against terrorist attacks that might include blast or fragmenta tion. Reinforced concrete barricades can provide effective protection against high-explosive devices; however; the high-intensity loadings f rom close-in explosions or fragment impact can create large magnitude, transient stress waves in concrete barricades that result in the gene ration of concrete spall on the back side of the barricade, even thoug h the barricade itself does not suffer general failure. Concrete fragm ents generated by concrete spallation can be hazardous to personnel an d equipment, depending on the size and velocity of the fragments. In t his study, a numerical model was developed to predict spall damage to concrete walls from close-in explosions in air for cased and uncased m unitions. The model was used to develop guidelines for designing concr ete walls to prevent spallation.