Punching shear is one of the critical concerns in the design of flat slab systems. This research is conducted to investigate the effect of different parameters regarding shear reinforcement on the punching strength of flat slabs. These parameters include yield stress of stirrups, extension of stirrups from column face along slab span, slab thickness, and the shape of stirrups whether multiple leg stirrups or closed stirrups. The experimental program in this research included testing eight slab specimens with dimensions of 1200 × 1200 mm and a thickness of 160 mm and 200 mm. The results of the experimental work were compared to those estimated according to local and international building codes. The results showed that using closed stirrups greatly increased the punching capacity of flat slabs even for a thickness of 160 mm.

One of the major advantages of using glass fiber-reinforced polymer bars as a replacement to the traditional steel-reinforced bars is its lightweight and high-resistant to corrosion. This research focuses on the performance of concrete beams partially/fully reinforced with glass fiber-reinforced polymer bars with 50% of GFRP bars were used to reinforce partially concrete beams at flexural zone. While 100% of GFRP bars were used to reinforce fully concrete beams at flexural and compression zones with different concrete compressive strength.This study reported the test results of 6 reinforced concrete beams with dimensions 150 × 200mm and a 1700-mm clear span length subjected to a four-point loading system. The tested beams were divided into three groups; the first one refers to the glass fiber-reinforced polymer bar effect. The second group is referring to the effect of concrete compressive strength, while the third group is referring to the effect of the GFRP bar volume ratio.Using longitudinal GFRP bars as a full or partial replacement of longitudinal steel bar reinforcement led to an increase in the failure load capacity and the average crack width, while a decrease in ductility was reported with a lower number of cracks. Increasing the concrete compressive strength is more compatible with GFRP bar reinforcement and enhanced the failure performance of beams compared with normal compressive strength concrete.

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