Structural behavior prediction of SFRC beams by a novel integrated approach of X-ray imaging and finite element method

Several studies have revealed that the fiber distribution is usually not uniform since many parameters during the fabrication process cause different fiber distributions and orientations within individual steel fiber-reinforced concrete (SFRC) members. This phenomenon results in large scattering in the post-cracking flexural responses among the material characterization specimens. Consequently, when estimating the flexural behavior of SFRC beams, conflicting results are often obtained using only a single constitutive stress-crack opening laws to characterize the material behavior in tension without considering the different fiber distributions and orientations. In this paper, a novel integrated approach is established to estimate the flexural behavior of SFRC beams using both a finite element (FE) method and X-ray imaging. In the prediction approach, a parameter that can be determined using the measured fiber distribution properties from an X-ray image is proposed to consider the variability of the fiber dispersion in each SFRC member. A method is presented for deducing the constitutive stress-crack opening laws using an FE analysis and the proposed parameter from X-ray images. In the numerical FE method, the variability of the fiber dispersion of the individual SFRC beams is determined by identifying the stress-strain relation in each mesh based on the proposed parameter from the X-ray images. The FE method provides better prediction results of the loading capacity for the SFRC beams.