INVESTIGATING BOUNDARY CONDITION VARIATIONS ON ULTIMATE LOAD CAPACITIES OF EDGE-RELEASED REINFORCED CONCRETE SLABS

The work conducted a detailed numerical and analytical investigation to precisely quantify the influence of a variety of accurate support conditions on the collapse mechanisms of single-spanned reinforced concrete slabs. Sample size specimen of slab of 500mm by 500mm by 75mm thick with varying support conditions were cast and tested at 28 days to determine the failure and crack loads at the application of the uniformly distributed loads. From the experimental analysis it was observed that all the effectively supported conditions (SA, SB, SC) show positive correlation between beam depth and load capacity and that the 3-edge free condition (SD series) shows moderate improvement with increased beam depth but at significantly lower absolute capacity, then using the ANOVA-Regression, it shows that for every 1mm increase in the beam depth the peak force increased by 2.15 KN showing a strong positive correlation with strength of p = 0.003 implying that both beam depth and support type are statistically significant predictors since p < 0.05. Slabs with partial or full edge release exhibit substantially reduced strength between 40% to 70% relatively to fully supported slabs. Beam stiffness contributes most effectively when boundary supports offer higher rotational restraint thereby delaying crack initiation and enhancing ductility