Finite Element Modelling of CFRP-prestressed Structural Concrete

This paper introduces a Finite Element framework for modelling reinforced and CFRP-prestressed concrete structures. A standalone Finite Element solver employing layered Reissner-Mindlin shell elements tailored for reinforced concrete applications is introduced and verified. Material nonlinearities – introduced by the implemented mechanical model based on the Tension Chord Model and the Cracked Membrane Model – are solved with Newton–Raphson iterations based on complex-step derivatives of the element stresses. The presented Finite Element framework is verified against three experimental campaigns covering (i) hyperstatic slab strips with hybrid steel/CFRP reinforcement, (ii) CFRP-prestressed T-beams, and (iii) a full-scale CFRP-prestressed railway bridge prototype. Good agreement between experimental results and model predictions is achieved in terms of (i) load-deformation behaviour, (ii) reinforcement stresses, (iii) crack widths, and (iv) failure analysis, where the latter is subject to assumptions regarding the representative failure volume.