Epistemic uncertainty of plane-stress continuum concrete models

Abstract

This article deals with the epistemic uncertainty of plane-stress finite element (FE) models. It is well known thatthe nonlinear response of reinforced concrete structures is strongly dependent on the stress-strain constitutiveconcrete models adopted. Herein, this uncertainty is evaluated using six different continuum constitutiveconcrete models, which are very popular in FE software. Because several of these models fail to converge instrain-softening regimes, modified models are proposed for their consistent plane-stress numericalimplementation. The six concrete models studied are: (i) the hyperbolic Drucker-Prager (DPH) plastic model; (ii)the Lubliner-Lee-Fenves (LLF) plastic-damage model; (iii) the Unilateral (UNI) damage model; (iv) the Wu-Li-Faría (WLF) model; (v) the Faría-Oliver-Cervera (FOC) model; and (vi) the total strain rotating (ROT) smearedcrackmodel. All models have been implemented in ANSYS software using user-material FORTRAN routines,which are adequate for shell-type finite elements. Results were validated using a set of experimentalbenchmark tests subjected to uniaxial and biaxial stress states under monotonic and cyclic loadings. Epistemicuncertainty in the model responses are qualitatively described and quantified as well.