Effect of Crimped Steel Fiber Ratios on Punching Shear Strength of Lightweight Concrete Slabs

Punching shear failure is an unfavorable failure mechanism that happens abruptly with little displacement in reinforced concrete flat slabs subjected to focused stress. A localized punching failure in one column increases the shear force acting on the surrounding columns. This could cause the adjoining columns to also experience a punching failure, ultimately resulting in the progressive collapse of the entire structure. In a way akin to a chain reaction, progressive collapse is the term used to characterize the propagation of an initial local failure within a structure, which may lead to a partial or complete collapse. This paper aims to investigate the impact of steel fiber on the punching shear of lightweight slabs. Three slabs measuring 750 x 750 x 70 mm are created. Two percentage of crimped steel fiber are using the volume of steel fiber was (0.5, 1) %. The results showed It can be seen that the ultimate load capacity was increased by (47.36) and (76.05) respectively. For sample content (0.5 and 1) steel fiber compare to control slab (S1-L-W). The results showed that the use of crimped steel fiber improved the first crack load by (84, 182.9) % for slabs used crimped steel fiber. Overall, the findings of this study indicate that adding the crimped steel fibers have significantly increased the ultimate load capacity, Ductility and toughness of the tested RLWC slabs.