A new model for determining the shear strength of reinforced concrete
(RC) corbels, or brackets, is proposed in this paper. The model
is obtained by superimposing the shear strength contribution of the
strut-and-tie mechanism due to the cracked concrete and principal
reinforcement, and the strength contribution due to stirrups. The first
contribution is expressed by means of a limiting shear strength
expression, whereas the second is derived from the equilibrium of
the strut-and-tie mechanism in the presence of stirrups. An explicit
formula dependent on two coefficients is derived for the shear
strength of corbels. These two constants are calibrated on the results
of 243 test data, which can be found in the relevant literature. The
expression obtained in this way is compared to the ACI Code and the
most recently proposed formulas and computing procedures, and it
results as better fitting the measured shear strengths. On the basis of
results of this paper, a design formula is proposed.
