Shear strength of RC beams with defective stirrup anchorages

The effects of corrosion removing the end anchorages of stirrups were investigated by tests of beams in which up to 75% of the shear reinforcement lacked end anchorages. In some beams a further effect of corrosion was simulated by the lower main steel being half-exposed. A small number of bond tests were also performed on vertical bars of the same types as the stirrups. The beams' shear strengths agree well with simple truss model calculations made treating the effectiveness of web steel as being a function of its anchorages above and below shear cracks. A more complete model of actual behaviour is given by a modified truss system.