Aims: Study the repair and strengthening of the flat slab-edge column connections against
punching shear.
Study Design: Parametric study is carried out by varying the repair and strengthening number of
stirrups rows and the stirrups materials.
Methodology: This paper study the effect of using of Fiber Reinforced Polymers (FRP) systems to
strengthen and repair the flat slab-edge column connections subjected to punching shear. These
systems is an exterior stirrups manufactured from glass, carbon fibers and steel links. Test results
of thirteen half-scale specimens reinforced concrete flat slab-edge column connections were
prepared to be tested under vertical punching shear load. The experimental plan for this study
included one specimen not strengthened nor repaired which used as control specimen. Six
specimens strengthened by exterior stirrups manufactured from Carbon Fiber Reinforced Polymer
(CFRP), Glass Fiber Reinforced Polymer (GFRP) and steel links, respectively, three specimens
strengthened by one row and the another three strengthened by two rows. Six specimens repaired
by exterior stirrups manufactured from (CFRP), (GFRP) and steel links, respectively, three specimens repaired by one row and the another three strengthened by two rows. Also, the
experimental ultimate loads were compared to the calculated values according to ACI 440.
Results: The test results were the ultimate load, load-deflection relationships, punching shear
resistance, relative ductility, flexural stiffness & punching shear angle.
Conclusion: The test results illustrated punching shear strength increasing and an increasing in
flexural stiffness for the strengthened and the repaired specimens compared to the control one. In
addition, the strengthened and the repaired tested specimens illustrated enhancement in relative
ductility and increase in angle of punching shear. The calculated ultimate loads based on ACI 440
procedures were below the experimental ones by 32 to 66%. |
