Tests on seventeen 3.5m long reinforced concrete beams with epoxy bonded external reinforcement subjected to 4-point bending are reported. The variables included different adhesives, plate geometries, a jointed plate, glue-line thickness, partial bonding and multi-layered plates. The beams were also tested as-cast (for reference), plated without the concrete being cracked (plated as-cast) and plated after cracking (plated precracked). in general, the addition of the plates increased the maximum sustained load by 40 per cent and the load required to produce the first visible crack by 80 percent. Stiffnesses were increased by 190 per cent for the plated as-cast condition and 250 per cent when the plate was added after the beam had been cracked to a width 0.1 mm in the constant moment span. The type of failure that can occur when plates are separated from the beam by horizontal shear failure in the concrete, did not occur when wide plates were used. A limited analysis of the beam section showed good agreement with the experimental results for various specified conditions. (Author/publisher)
Samenvatting