Ayman Mohammad Mansour, Themelina Paraskeva, Nuha S. Mashaan
Traditional finite element modelling of Steel Fibre-Reinforced Concrete (SFRC) rely on homogenised macroscopic models that overlook localised effects such as fibre orientation and pull-out behaviour. This work introduces a tensor-controlled mesoscopic modelling approach that explicitly simulates individual fibres with random and preferential alignment, offering a more realistic representation of fibre bridging and failure mechanisms. A comprehensive series of 3D finite element simulations replicates the fracture response of SFRC beams subjected to three-point bending, in accordance with EN 14651. The simulation program comprises seven finite element models designed to systematically evaluate the effects of modelling scale, fibre dosage, and fibre orientation on the flexural behaviour of SFRC. To the authors’ knowledge, this is one of the first studies to systematically quantify the influence of controlled fibre alignment using a mesoscopic approach. These models were calibrated and validated against experimental results to ensure realistic material response and fracture behaviour. Comparative analysis revealed that the mesoscopic approach outperforms the macroscopic model in capturing post-cracking behaviour, fibre pull-out, and crack bridging mechanisms. Preferential fibre alignment significantly enhanced flexural performance, increasing residual strengths and promoting higher ductility classes, though with a modest reduction in the ductility index. The findings highlight the importance of fibre orientation in SFRC design and support mesoscopic modelling for detailed fracture behaviour analysis.