Influence of Concrete Strength and Load History on the Shear Friction Capacity of Concrete Members

T shear friction analogy is a design method which is familiar to most engineers in practice. rrr It is a valuable and simple tool which can be used to estimate the maximum shear force transmitted across a cracked plane in a reinforced concrete member. The cracks considered may be caused by load effects, but also by a variety of other reasons such as tensile forces due to restrained shrinkage or temperature deformations, or by accidental dropping. The shear friction method is used in the design of precast concrete structural connections for estimating the shear capacity of interfaces between precast members and cast-in-place concrete and for calculating the residual shear capacity of cross sections which are weakened by cracking. Well known is the application for the design of short corbels wherein a control of the interface stresses is necessary to prevent a possible shear failure (see Fig. 1). The role of shear friction in the design of corbels was treated by Mattock.tO Similarly, the principles concerning interface shear capacity can also be