Sectional analysis of the cyclic behavior of steel fiber reinforced concrete

摘要

Steel fiber reinforced concrete (SFRC) is known for improving the tensile post-cracking fatigue behavior of concrete. This paper presents a method to obtain the cyclic tensile behavior of SFRC through sectional analysis, using a limited amount of input parameters. The analytical model is divided into two parts: a monotonic and cyclic model. The monotonic model calculates the uniaxial stress-crack width curves or constitutive laws of SFRC that fulfill the beam's equilibrium with the smallest error. Afterwards, when the constitutive law is known, the cyclic model predicts the behavior during progressive load cycles. Two methods are used to implement the damage caused by cyclic loading: based on the experimental stiffness during cyclic direct tensile tests (DTTs) and based on a relation between the plastic crack width and the crack width at unloading. The latter option is preferred as no additional DTTs are needed. The proposed methodology therefore eliminates the need for challenging DTTs and only requires more feasible monotonic three-point bending tests (3PBTs) for model calibration. The model is validated by means of DTTs and cyclic 3PBTs and its potential for extension to fatigue loading is shown.