Shear Strength of Fiber Reinforced Reactive Powder Concrete Prestressed Girders without Stirrups

Experimental results from tests on seven 650 mm deep large-scale reactive powder concrete (RPC) I-section girders failing in shear are reported herein. The girders were cast using 150 170 MPa steel fiber RPC and were designed to assess the capacity to carry shear stresses in thin webbed prestressed beams without shear reinforcement. The tests showed that the quantity and types of fibers in the concrete mix did not significantly affect the initial shear cracking load but increasing the volume of fibers increased the failure load. A design model is developed to calculate the strength of the RPC beams tested in this study. The model is based on crack sliding and uses plasticity theory combined with observations from the variable engagement model for mode I failure of fiber reinforced concrete. The results of the model are compared with test data and show a good correlation.