DAMAGE RATIO STRENGTH CRITERION FOR STEEL FIBER REINFORCED CONCRETE UNDER MULTIAXIAL STRESSES

Based on the damage ratio strength theory, the true triaxial damage ratio strength criterion for steel fiber reinforced concrete (SFRC) was established. The six empirical parameters in the expression of the damage ratio variable of the criterion were recommended according to the test data of SFRC. The values of the damage ratio variable were verified by the experimental results of SFRC under uniaxial, biaxial and triaxial loading conditions, and the values of damage ratio of SFRC under uniaxial tension, uniaxial compression and biaxial equal compression stress conditions were compared with those of plain concrete. By comparing the predicted results with the experimental data of 104 SFRC specimens containing 0.5%~2.5% of fibers, against some strength criteria, the proposed criterion is verified that it can represent the triaxial failure surfaces of SFRC and give relatively good approximation of the experimental results. A simplified conventional triaxial damage ratio strength criterion for SFRC was proposed for confining triaxial stress state, and was compared with the existing conventional triaxial strength criteria. In addition, the empirical parameters of the simplified biaxial damage ratio strength criterion were recommended for biaxial stress states.