Abstract

KLEYNHANS, A; KEARSLEY, EP  and  SKORPEN, SA. The measured and modelled thermal response of reinforced concrete T-beams subjected to environmental loading. J. S. Afr. Inst. Civ. Eng. [online]. 2025, vol.67, n.3, pp.40-53. ISSN 2309-8775.  https://doi.org/10.17159/2309-8775/2025/v67n3a4.

In this study, the thermal response of two reinforced concrete T-beams with identical outer dimensions but differing internal geometry, and therefore different thermal inertia, is investigated. Both T-beams were instrumented with thermocouples and vibrating wire strain gauges and subjected to purely thermal environmental loading. The weighted average (effective cross-sectional) temperature, along with the vertical and transverse temperature distributions, were analysed. In addition, theoretical thermal strains and self-equilibrating stresses were calculated. Uniquely, the mathematical model and assumptions were compared to and validated by experimentally measured strains as opposed to validation through comparisons of predicted temperatures. Effective temperature ranges were related to cross-sectional area per unit width and compared to results from literature. Furthermore, the greatest difference in thermal response between the two sections was found to be effective temperature and subsequent longitudinal movement. Calculated bending moments, caused by thermal loading effects and self-equilibrating stresses, approached 30% of the concrete's ultimate tensile capacity, emphasising their structural relevance.

Keywords : reinforced concrete; thermal response; thermal inertia; cross-sectional geometry; environmental loading.

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