This study aims to determine the efficiency of
using Fiber Reinforced Polymers (FRP) systems to strengthen
the slab–column connections subjected to punching shear. The
used strengthening systems consisted of external FRP stirrups
made from glass and carbon fibers. The stirrups were installed
around the column. Also, external steel links were used as a
conventional strengthening method for comparison. Over the
last few years, the use of FRP for strengthening of concrete
structures has been investigated by many researchers,
whichconcerning with the strengthening of reinforced concrete
slabs, beams and columns. The use of FRP in strengthening
concrete slabs in flexure is done by bonding it to the tension face
of the slabs. The use of FRP for strengthening the flat slabs
against punching shear can be considered as a new application.
This research shows the results obtained from an experimental
investigation of 4 half-scale two-way slab-column interior
connections, which were constructed and tested under punching
shear caused by centric vertical load. The research included one
unstrengthened specimen, which considered as control
specimen, one specimen strengthened with steel links, one
specimen strengthened with external stirrups made from Glass
Fiber Reinforced Polymer (GFRP), and one specimen
strengthened with external stirrups made from Carbon Fiber
Reinforced Polymer (CFRP). So, the type of strengthening
material is the basic parameter in this study. The experimental
results showed a noticeable increase in punching shear
resistance and flexural stiffness for the strengthened specimens
compared to control specimen. Also, the strengthened tested
slabs showed a relative ductility enhancement. Finally,
equations for punching shear strength prediction of
slab-column connections strengthened using different materials
(Steel, GFRP & CFRP) were applied and compared with the
experimental results. |
