Biaxial hollow slab is a type of slab, in which concrete from the middle of the slab (floor) has been eliminated by void formers (bubbles). Its main advantage is reduction in self weight (about 30-50%). This type of slab system is mainly used as reinforced concrete flat slab, which are more vulnerable to punching shear failure. In this study, simulations have been carried out by using finite element software DIANA (Displacement Analyzer) to investigate the punching shear capacity of the biaxial hollow slab. Parametric studies have been done to compare the effect of fracture energy on punching shear capacity; furthermore the study has been extended to investigate the effect of voids on the deflection of the slab.

Keywords: Biaxial hollow slab, Punching shear and voided slab.