Fibre reinforced plastic, FRP, shear bolt system has been recently developed at the University of Waterloo, Canada. The system can be used to protect existing reinforced concrete slabs against brittle and sudden punching shear failure. The retrofit procedure requires drilling small holes in a slab around the perimeter of a column, inserting bolts into the holes and anchoring the bolts at both external surfaces of the slab. Many existing reinforced concrete slabs had been built without any shear reinforcements. Also, many of these slabs are in corrosive environments, e.g. in parking garages where the use of de-icing salts accelerates reinforcement corrosion and concrete deterioration. Therefore, FRP is an ideal material to be used for such retrofit. The challenge, however, has been the development of mechanical end anchorages for FRP rods that is efficient, aesthetic, cost effective, and that can be applied on-site. In the presented research six isolated slab-column specimens were constructed representing interior slab-column connections in a continuous flat plate slab system. The specimens were subjected to simulated gravity and gravity plus seismic loadings. A new anchorage technique for the FRP rods was developed, which is based on crimping the rod ends with the aluminum fittings. Using this approach, fairly large loads can be resisted by the end-fittings. The developed FRP bolts worked very well improving the performance of the slab-column connections and showing the benefits of using FRP in punching shear retrofit of reinforced concrete slabs.
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