Shear strengthening of reinforced concrete beams

In recent years reinforced. concrete structures are subject to many causes ofdistress.The strengthening of structural systems is an important aspect of the renovationof concrete structures.The prolongation oJ service life and the increase oJ load carrying capacity of different types oJ structures required at present. and will be required even more in the future, new approaches in addition to the established methods.Some oJ dijJerent techniques, that are widely used in repair and strengthening of reiriforced concrete beams in shear, are studied in this thesis.Thirty Jour reinforced. concrete beams were tested experimentally in this study.Two beams were considered as reference beams, having sulficient web reinforcement in the shear span., and tested up to Jailure.Four beams were considered as base beams, two oJ them, had no webreinforcement in the shear span while the other two beams were provided withinsufficient web reinforcement in the shear span. These beams were tested up to failure.Twenty-eight beams were loaded primary up to twice the cracking load, thenstrengthened using various methods, and then reloaded up to [ailure.The dijJerent methods oJ strengthening were conjming the shear span by 1.5 cmepoxy mortar Jacket with or without additional web reinforcemerit. Two types of stirrups were used, vertical and inclined with dijJerent diameters.The cracking load, crack pattern. ultimate load and modes oJ failure wererecordedJor each beam. Also the dejlectiotis were measured with every load increment.Some relations and recommendations which may be useJul Jar designer beJoreclwosing the technique and carrying out the strenqihenuiq process are introduced.