Punching Shear Behavior of Polymer Nanocomposite Flat Slabs with Shear Reinforcement under Monotonic Loading

Abstract

This study investigates the punching shear response of flat slabs made with polymer nanocomposite materials and different amounts of shear reinforcement under monotonic loading. Eight slab models were analyzed using three-dimensional finite element analysis, including both normal concrete and polymer nanocomposite slabs. The results show that adding shear reinforcement increases the load the slabs can carry and limits their deformation. In the polymer nanocomposite models, the ultimate load increased from 525 kN without shear reinforcement to 562.5 kN with Ø12 shear reinforcement, while the maximum deflection was reduced by up to 38.1%. Compared with the normal concrete models, the polymer nanocomposite slabs carried 45–55% higher loads and dissipated up to 238% more energy. The higher stiffness and shear resistance obtained with additional reinforcement were accompanied by a small reduction in ductility, indicating a stiffer response before failure. The stress contours also showed that larger shear reinforcement diameters spread the stress over a wider region and reduced the concentration around the column. Taken together, the results show that polymer nanocomposite materials can improve the punching shear response of flat slabs, particularly when combined with suitable shear reinforcement.