A flat slab is an efficient structure in resisting gravity loads by transferring the load from the slab to the columns and then to the foundations. Various normal concrete (NC) flat slab reinforcements against punching shear have been developed, including drop panels, steel plates, aluminum plates, additional longitudinal bar reinforcement, steel tubes, and transverse reinforcement. However, previous studies have not discussed the effect of the transverse reinforcement ratio that impacts capacity and ductility. In contrast, the performance of flat slabs with environmentally friendly concrete, such as geopolymer concrete (GC), has not been discussed. This study aims to analyze the performance of GC flat slabs reinforced with transverse reinforcement. The novelty of this study is extending the NC flat slab test results to GC flat slab numerical models with different transverse reinforcement. The performance of NC and GC flat slabs subjected to monotonic downward vertical loads is analyzed using a finite-element-based software. The issues discussed include shear load, deflection, stress contour, displacement contour, ductility, stiffness, energy absorption, and punching shear capacity. The results show that transverse reinforcement increases the flat slab capacity to withstand punching shear loads. The GC materials enhance shear strength. However, excessive transverse reinforcement results in brittle behavior and reduces deformation, ultimate load, and ultimate deflection.
