Numerical investigation of the structural response of eccentrically loaded reinforced concrete columns exposed to non-uniform heating and cooling

This paper explores the applicability of advanced numerical models to the complex structural behaviour observed when symmetrically reinforced and eccentrically loaded concrete columns are subjected to non-uniform heating regimes. To this end, attention is focused on a recently completed experimental campaign specifically aimed at providing a novel data set on the performance of reinforced concrete members subjected to several combinations of loading, heating, and cooling conditions. The structural behaviour of the columns was studied using 3D finite element models developed using commercial software by means of sequentially-coupled thermomechanical analyses. A user subroutine was developed to model the mechanical properties as irrecoverable in the cooling phase. The results obtained show that, on the whole, the structural behaviour can be adequately represented by the numerical model. Moreover, the roles of thermal and transient deformations are correctly captured, as well as the possibility of failure in the cooling phase.