Numerical-aided flexural-based design of fibre reinforced concrete column-supported flat slabs

摘要

The growing use of fibre reinforced concrete (FRC) for structural purposes has led several guidelines to include design-oriented models that allow the partial (and even total) substitution of the steel reinforcing bars. Among those, fibres as concrete reinforcement for elevated concrete flat slabs is gaining interest due to the identified technical and benefits and quantified sustainability enhancements. However, although this technology has already been used in buildings and its sufficient bearing capacity confirmed by real-scale experimental programs, its straightforward implementation is far from being consolidated. The latter is owing to the existence of several paramount aspects to be answered. One of those is the influence of the fib MC-2010 FRC post-cracking strength classification, including the combination of steel bars, on the mechanical response of these elements at ULS and SLS. In this context, a non-linear finite element model was implemented and validated by means of results from existing real-scale tests. Posteriorly, the model was used to design a new real-scale test to be performed within the context of the research project eFIB (from the Spanish, Optimization of Construction Processes of Structural Elements by using Fibre Reinforced Concretes). To this end, a parametric study was developed by considering several FRC post-cracking strength classes, using fibres as unique reinforcement or combined with steel meshes, to determine an optimum solution for flexure (which governs the main reinforcement requirements) based on the structural reliability index targeted for building construction. The model results and analysis permitted to derive relevant conclusions from the material design optimization point of view, which can be a reference for future similar experiences.