Strengthening of concrete haunched beams with epoxy bonded external
steel side plates in shear is becoming on increasing by popular retrofit
technique among researchers and engineering worldwide. Concrete of higher
compressive strength have been produced currently, and increasingly used by
the designers and contractors. Therefore, the main purpose of the research
described in this paper is to give better and full understanding of the shear
behaviour of high strength concrete rectangular beams strengthened with
epoxy bonded external steel side plates and subjected to static load. The main
variables studied were the geometric dimensions of bonded steel plates, width,
position and arrangements, thickness of plate bonded on both sides of shear
zone of beams, the effect of haunches (Negative haunches (-0.20) and positive
haunches (+0.20)) and effect of quality degree of used concrete strength.
During the tests cracking load, ultimate load, concrete strains, steel strains
and deflection under load application were measured
Test results showed that the width, position, arrangements and thickness of
plate used considerably affects strength, deformation and mode of failure of the
tested beams. Increasing the width, position, arrangements and thickness of
plate bonded on both sides of shear zone of beams increases the cracking and
ultimate capacities of the strengthened beams. Increasing the quality degree of
concrete strength decreases the relative cracking and ultimate capacities of the
strengthened beams compared to unstrengthened beams. The change from
positive haunches (+0.20) to Negative haunches (-0.20) increases the cracking
and ultimate capacities of the strengthened beams.