A Direct and High-Efficiency Approach to Accurately Simulating Overall Bending Responses of Ultra-High Performance Fiber-Reinforced Concrete Beams up to Failure

A direct and high-efficiency approach is established toward bypassing usual analytical and numerical complexities in analyzing elastoplastic flexural behaviors of ultra-high performance fiber-reinforced concrete (UHPFC) beams until failure. Both the varying neutral axis and the flexural moment are in a direct and explicit manner determined from the flexural curvature. Accurate results are obtainable to various cases of both the cross-sectional shape and the rebar reinforcement. Novelties in a few respects are incorporated. First, within a general constitutive framework of finite elastoplastic deformations with failure effects, it is disclosed that the stress distributions over the tensile and the compressive zone can be prescribed just by uniaxial tensile and compressive stress-strain functions of ultra-high performance concretes from hardening to softening. Then, the latter two can further be given in explicit forms. Eventually, the elastoplastic bending problem is accordingly reduced to a simple issue of fitting these forms to tension and compression data from uniaxial testing. Numerical examples are provided for both rectangular and I-shaped UHPFC beams with rebar reinforcement. Model predictions are in good agreement with experimental data.