Investigating the flexural behaviour of biaxial voided slab with varying size and spacing of cuboidal shaped void formers with innovative type of fixing reinforcement

The biaxial voided slab is an advanced slab system that offers a more efficient alternative to traditional reinforced concrete slabs by incorporating voids of various shapes of void formers have been utilized in previous studies, such as spherical, elliptical, and donut shapes. To investigate the effect of void size, shape and spacing especially on the flexural performance of biaxial voided slabs experimental investigations were conducted in this study on five voided slab specimens employing five distinct sizes of cuboidal-shaped void formers. The obtained results were then compared with solid slab as a control specimen. Two way bending test was performed over the specimens under sixteen-point loading. An innovative type of fixing reinforcement was proposed to fix the voids into their positions which also helps to improve the structural capacities of voided slab. Theoretical investigations of ultimate load carrying capacity, flexural stiffness and deflections were carried and compared it with the experimental results. Nonlinear finite element analysis (FEA) was carried using ABAQUS program, and then it was validated with the experimental results. The ratio of void width to void spacing (b/s) was introduced to examine the impact of void size and spacing on flexural strength of voided slab through parametric analysis over 30 voided slab specimens. Experimental and Numerical results revealed that an increase in void size leads to a noticeable decrease in stiffness, affecting the ultimate load carrying capacity leading towards the failure of the slab.