Thermo-Hygro-Mechanical Simulation of Cracking in Thick Restrained RC Members: Application to a 50 cm Thick Slab

Abstract

The calculation of crack width in thick, restrained, reinforced concrete (RC) members has relevance, either at the design stage or during the assessment of existing structures. This type of structural element exhibits a complex serviceability behaviour, due to the nonlinear self-induced deformations caused by cement hydration and shrinkage, and also the interaction between primary cracks and secondary cracks which do not fully penetrate in the cross section. In this context, this paper presents a staggered thermo-hygro-mechanical (THM) analysis methodology, based on the finite element method (FEM), for calculation of the long-term development of self-induced deformations, stresses and cracks, since casting, at the macro scale. A comprehensive approach is followed, in which the mechanical material models are defined as a function of the calculated thermal and hygral fields. This analysis methodology is applied in the study of the crack formation in end restrained slab-like RC members, with a thickness of 50 cm, a parametric analysis in conducted in order to gain insight about the influence of some relevant structural and material variables.