Title: Punching Shear Behavior of Flat Slabs Reinforced with Glass Fiber-Reinforced Polymer Bars

Author(s): Christian Dulude, Mohamed Hassan, Ehab A. Ahmed, and Brahim Benmokrane

Publication: Structural Journal

Volume: 110

Issue: 5

Appears on pages(s): 723-734

Keywords: fiber-reinforced polymer; flat slab; punching shear; slab; slabcolumn; thickness; two-way

DOI: 10.14359/51685826

Date: 9/1/2013

Abstract:
Results from an experimental study aimed at investigating the behavior of full-scale two-way flat slabs reinforced with glass fiber-reinforced polymer (GFRP) bars and subjected to monotonically increased concentrated load are presented. A total of 10 interior slab-column prototypes measuring 2.5 x 2.5 m (98 x 98 in.) were constructed and tested up to failure. The test parameters were: 1) reinforcement type (GFRP and steel) and ratio (0.34 to 1.66%); 2) slab thickness (200 and 350 mm [7.9 and 13.8 in.]); and 3) column dimensions (300 x 300 mm [11.8 x 11.8 in.] and 450 x 450 mm [17.7 x 17.7 in.]). All test prototypes showed punching shear failure and the crack patterns at failure were almost the same regardless of reinforcement type or ratio. Besides, the GFRP‑reinforced prototypes showed lower punching capacity compared to that of the steel-reinforced ones when the same reinforcement ratio was employed due to the lower modulus of GFRP bars compared to steel. Predictions using different design guidelines were compared to the experimental results obtained herein. The comparisons showed that the ACI 440.1R equation yielded very conservative predictions with an average Vtest/Vpred equal to 2.10 ± 0.30.