A multiaxial load-induced thermal strain constitutive model for concrete

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:108

Article

Torelli, Giacomo¹  Gillie, Martin¹  Mandal, Parthasarathi¹  Tran, Van-Xuan² 

[1] Univ Manchester, Sch Mech Aerosp & Civil Engn, Manchester M13 9PL, Lancs, England

[2] EDF Energy, R&D UK Ctr, 40 Grosvenor Pl, London SW1 7EN, England

关键词: Concrete;    Temperature;    Fire;    Load-induced thermal strain;    Transient thermal creep;    Thermal strain;    Stress confinement;    Modeling;   

DOI  :  10.1016/j.ijsolstr.2016.11.017

来源: Elsevier

【 摘 要 】

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 degrees 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 degrees 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. (C) 2016 The Authors. Published by Elsevier Ltd.

【 授权许可】

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