Shear strengthening effect by bonded GFRP strips and transverse steel on RC T-beams

Abstract

This study focuses on shear strengthening performance of simply supported reinforced concrete (RC) T-beams bonded by glass fibre reinforced polymer (GFRP) strips in different configuration, orientations and transverse steel reinforcement in different spacing. Eighteen RC T-beams of 2.5 m span are tested. Nine beams are used as control beam. The stirrups are provided in three different spacing such as without stirrups and with stirrups at a spacing of 200 mm and 300 mm. Another nine beams are used as strengthened beams. GFRP strips are bonded in shear zone in U-shape and side shape with two types of orientation of the strip at <TEX>$45^{\circ}$</TEX> and <TEX>$90^{\circ}$</TEX> to the longitudinal axis of the beam for each type of stirrup spacing. The experimental result indicates that the beam strengthened with GFRP strips at <TEX>$45^{\circ}$</TEX> orientation to the longitudinal axis of the beam are much more effective than <TEX>$90^{\circ}$</TEX> orientation. Also as transverse steel increases, the effectiveness of the GFRP strips decreases.