A multiaxial load-induced thermal strain constitutive model for concrete

Torelli, Giacomo, Gillie, Martin, Mandal, Parthasarathi and Tran, Van-Xuan (2017) A multiaxial load-induced thermal strain constitutive model for concrete. International Journal of Solids and Structures, 108. pp. 115-125. ISSN 0020-7683

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Official URL: https://doi.org/10.1016/j.ijsolstr.2016.11.017

Abstract

The paper presents a novel thermomechanical 3D Load-Induced Thermal Strain (LITS) model that captures the experimentally demonstrated behavior of concrete in the case of heating under multiaxial mechanical load, for temperatures up to 250 °C. In contrast to the models available in the literature, the new model takes into account the observed dependency of LITS on stress confinement. Such a dependency is introduced through a confinement coefficient which makes LITS directly proportional to the confinement of the stress state. Also, a new practical bilinear LITS model is proposed and proved to be suitable for fitting the general trend of the curves experimentally obtained for different loading conditions. The presented model is embedded in a thermoelastic material constitutive law, and then verified and validated against experiments performed on concrete specimens subjected to transient temperatures up to 250 °C under uniaxial, biaxial and triaxial compressive stress states. Once calibrated and validated, the constitutive model is used to evaluate the effects of LITS on the structural behavior of a Prestressed Concrete Pressure Vessel (PCPV) of a typical Advanced Gas cooled Reactor (AGR) subjected to a heating-cooling cycle simulating a temporary fault in its cooling system. The results of this study indicate that the development of LITS significantly influences the stress redistribution in the structure. Moreover, it is shown that in the case of PCPVs (and by extension similar structures) it is crucial to consider the LITS dependence on the stress confinement.

Item Type: Article
Uncontrolled Keywords: Concrete, Fire, Load-induced thermal strain, Modeling, Stress confinement, Temperature, Thermal strain, Transient thermal creep
Subjects: H300 Mechanical Engineering
H700 Production and Manufacturing Engineering
H900 Others in Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: Rachel Branson
Date Deposited: 15 Jul 2020 10:57
Last Modified: 15 Jul 2020 11:00
URI: http://nrl.northumbria.ac.uk/id/eprint/43784

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