SECTIONAL ANALYSIS OF STEEL FIBER REINFORCED CONCRETE BEAMS USING MODIFIED COMPRESSION FIELD THEORY

Based on the characteristics of steel fiber reinforced concrete, averaged principal stress-strain relationships for cracked concrete of modified compression field theory (MCFT) are modified. Then a new sectional analytical model for steel fiber reinforced concrete beams under the combined action of bending moment and shear is established by adding the bending moment action into the model of Vecchio and Collins, a sectional analysis model for reinforced concrete membrane element under pure shear. The new model is tested by the experiments of the authors and other researchers. Computing predictions for the ultimate load and the dependence between shear and strain of stirrup of steel fiber reinforced concrete beams obtained by the model show a good agreement with their practically observed counterparts. The efficiency of steel fibers and stirrups improving shear behavior of the beams are also compared through the new model.