Experimental and numerical study on cracking process in RC and R/FRC ties

A numerical non-linear procedure able to represent the behavior of cracked steel fiber reinforced concrete (SFRC) is herein presented and verified. The involved post-cracking mechanisms, particularly tension softening and tension stiffening, have been investigated and properly taken into account. Different tension softening relationships have been implemented and discussed, one based on a micro-mechanical approach, another obtained from inverse analysis and finally the Model Code 2010 (MC2010) law. These models have been adopted in conjunction with a smeared crack approach to perform FE simulations of R/FRC ties characterized by different cross-sections and fiber volume fractions. Numerical results have been validated against a comprehensive experimental program on R/FRC (characterized by a tension softening behavior) and RC ties recently carried out at the University of Brescia. Comparisons between experimental and numerical results indicate that smeared models can be adopted also for the analysis of this structural typology, subjected to a uniaxial state of stress, as a valuable alternative to discrete approaches.