Investigation of the performance of RC slabs using hybrid reinforcement of geogrid and steel reinforcement

This article explores the impact of uniaxial geogrid type and steel reinforcement bars on the flexural behavior of two-way solid slabs. It uses analytical, numerical, and experimental studies on eight square slab specimens, with uniform loads applied until failure. The study classifies the specimens into five groups based on studied parameters. The investigated parameters were the effect of using the geogrid (with or without geogrid), the number of layers, the dimensions of the geogrid layer, and its position through the slab thickness. The study measured cracks and failure loads, deflections, failure modes, crack propagation, and patterns, and evaluated the ductility features of all specimens using displacement ductility factors.The experiments showed that using uniaxial geogrid meshes as a two-way concrete slab's reinforcement was more reliable than using conventional steel bars. This resulted in a 13% increase in failure load, 138% increase in initial stiffness, and 85% increase in energy absorption.Also, by using two layers of geogrid above the steel bars, the slab’s failure load and energy absorption increased by 8% and 12%, respectively, compared to a slab reinforced with three layers of geogrid above the steel bars. Different analysis methods were employed to verify experimental results based on the nominal flexural strength of the ECP 203-19 code[1]. The results showed that the ECP 203-19 code should be considered as a good method to find the slab’s ultimate load, where the average and the standard deviation were 96% and 19%, respectively.