Shear strengthening of RC members using FRP may be provided by bonding the external reinforcement with the principal fiber direction as parallel as practically possible to that of maximum principal tensile stresses, so that the effectiveness of the FRP is maximized. For the most common case of structural members subjected to lateral loads, the maximum principal stress trajectories in the shear-critical zones form an angle with the member axis that may be taken roughly equal to 45o. However, it is normally more practical to attach the external CFRP reinforcement with the principal fiber direction perpendicular to the member axis (Fig. 2-22).