Experimental investigation into the shear resistance of a reinforced UHPFRC web element

Ultra-high performance fiber reinforced concrete (UHPFRC) can be implemented in combination with steel reinforcing bars to enhance the performance of UHPFRC elements subject to shear stresses. This paper presents an experimental investigation into the behavior of a UHPFRC web element in shear. Two I-shaped beams are constructed out of UHPFRC, with longitudinal reinforcing bars in the tension flange. One of the beams includes transverse bars in the web; the other contains no transverse bars. When loaded to failure in a three-point bending test, the specimen with transverse bars exhibits greater shear strength than the specimen without transverse bars. The observed strengths of both specimens show good agreement with a proposed expression for estimating the shear strength of UHPFRC elements. The proposed expression is based on a truss model for shear resistance, and it treats UHPFRC fibers as reinforcement with a variable angle of inclination, bridging shear cracks at an angle perpendicular to the length of the crack.