Revisiting the fib blind competition: insights into the numerical modeling of steel-fiber reinforced concrete beams

Resumo

The second blind simulation competition (BSC) organized by the fib WG 2.4.1. took place in 2021 proposing the numerical modeling of a hybrid fiber reinforced concrete (R/FRC) shallow beam to assess the predictive performance of FEM-based computational models on the design verification at serviceability and at ultimate limit state conditions (SLS and ULS, respectively). This work revisits this benchmark aiming to address two issues not detailed in the BSC. The commercial finite element software DIANA is the chosen numerical tool, in which a classical smeared crack model is used to simulate the FRC properties and bar elements to represent the longitudinal reinforcement. It is shown that the modeling of the steel/FRC bond plays as important role in the structural behavior at SLS. It also discusses the influence of the modeling of the FRC compressive properties on the structural behavior at ULS by applying three different curves. The better correlation between the numerical results and the 2nd BSC experimental tests are obtained by using the parabolic compression curve for the FRC and the no-failure bond-slip interface model for the steel/FRC connection.