EXPERIMENTAL STUDY ON SHEAR PERFORMANCE OF PREPRESSED CONCRETE HOLLOW SLAB BEAMS REINFORCED BY GROUTING

In order to reinforce the oblique web shear crack in the shear span of prestressed concrete hollow slab beams, grouting reinforcement at the end of the hollow slab beam is proposed to increase the shear cross-sectional area of the hollow slab. The shear resistance test was carried out on three full scale 20 m pre-tensioned concrete hollow slab beams, to verify the mechanical properties and the reinforcement effect of grouting reinforcement. The grouting length was 1.5 m, 2.0 m, 2.5 m respectively. The concrete strain, stiffness, bearing capacity, deflection and crack distribution were analyzed for the test specimens under different grouting lengths. Through the comparison with the test results of unreinforced beam, the improvement on shear bearing capacity of reinforced beam was demonstrated. The result shows that the overall stiffness of the beam has slight change under normal service load, and no oblique web shear crack occurs in the shear span of the slab beam, but the shear capacity of the beam is greatly improved. The failure mode of the beam with grouting reinforcement is the bending shear failure at the intersection of the strengthened and the un-strengthened parts.