Abstract
Voided flat slabs, a specialized form of conventional solid flat slabs, incorporate void formers in minimally contributing strength areas. While this method reduces concrete volume and offers advantages, it raises significant concerns regarding shear resistance. Current design codes do not provide precise provisions for estimating the one-way shear capacity of these systems, leading to potential safety issues in structural design. This study investigates the shear behavior of voided flat slabs through a comprehensive parametric analysis. Key geometric parameters assessed include void height (100 mm to 140 mm), slab thickness (220 mm to 320 mm), and shear span (600 mm to 900 mm). A nonlinear finite element analysis model was developed and validated against experimental data, showing strong agreement with results. The study analyzed 84 slab specimens, comprising 52 voided slabs and 32 solid slabs, with variations in key parameters to evaluate their impact on shear performance. The findings indicate that the presence of voids reduces the shear capacity of slabs, with the extent of reduction varying based on geometric configuration. Voided slabs with lower void heights and greater thicknesses retained up to 87.9% of the shear strength of solid slabs, while thinner slabs with larger voids retained 62%. Shear capacity increased with decreased shear spans, particularly in thicker slabs, due to enhanced effective depth that amplified the capacity to transmit shear stress.