This research seeks to examine punching shear reinforcements using various materials and
techniques, then evaluate their effectiveness in order to increase the punching strength of flatslab-
column connections (FSCC). Additionally, a novel strengthening method utilizing FRP
ropes was suggested and investigated. In this study, sixteen FSCC with cross sections of (1600 ×
1600 × 150) mm and stub columns with a cross section of 200 × 200 mm and a total height of
700 mm extended outside both sides of the slab were constructed and tested. The transverse
reinforcements "stirrups" have been varied in [material types - spacing - width- shapes]. The
variables were: the materials used (steel, CFRPs "carbon fiber reinforced polymers", GFRPs "glass
fiber reinforced polymers"), spacing between stirrups (30, 50, 70 mm), the width of stirrups (140,
280 mm, and variable width stirrups as a novel scheme), and Case condition (internal reinforcement
or external strengthening). The experimental results indicated a significant increase in
punching shear resistance for the FSCC reinforced with stirrups by 25–85 % when compared to
the control specimen. The results demonstrated the superiority of the CFRP as a strengthening
material over any other materials, also, the novel scheme proposed in this study (variable width
stirrups) gave the highest punching capacity compared to the identical case slabs. To validate the
experimental results, a finite element analysis using ABAQUS/CAE6.14 was performed, and the
results were very close to the experimental one. Moreover, theoretical equations have been
verified on the experimental specimens. Finally, experimental, theoretical, and analytical results
were compared. The novel scheme and CFRP stirrups were recommended to use for enhancing the
punching shear resistance. |
