Effect of beam depth on shear behavior of FRP RC beams

The behavior of shear critical fiber-reinforced-polymer (FRP) RC elements is characterized by the development of comparatively large strains and crack widths, which can be strongly influenced by their relative geometrical size. This paper investigates experimentally the size effect on the shear behavior of FRP RC beams with and without shear reinforcement and with overall depth varying from 260 to 460 mm. The results confirm a considerable size effect for members without shear reinforcement, with an average reduction in normalized shear strength of about 19% and a maximum value up to 40%. It is also shown that current design provisions are overall conservative, but with nonuniform margins of safety that decrease with increasing member depth. It is anticipated that the results of this study will help improve the efficiency of future design equations for the shear strength of FRP RC.