Concrete experiences transient strain due to thermal loadings, which is attributed to thermo-mechanical interaction within the cement paste. A number of mathematical models have been proposed in the literature to assess transient creep strain component at elevated temperature. The objective of this paper is to address the implication of using an alternative transient strain model on the global behavior of heated RC columns. A numerical approach is presented through which mathematical formulations are incorporated to evaluate the axial load response of RC columns subjected to a fire environment. The analytical approach captures the effect of pre-loading intensities, aggregate types, section sizes, and temperature-dependent material properties on the axial load response of the RC columns. This work is divided into two parts. The first part presents review on the available constitutive formulations to highlight concrete and steel thermo-mechanical behavior during the heating process. The second part describes development of the proposed technique, where the method entails discretisation of an RC cross-section to monitor the temperature distribution within the section. The appropriate number of elements to describe the cross-section was determined based on a sensitivity analysis approach. Following this, the analyses were carried out based on the optimized number of elements for further column specimens. The numerical assessment was carried out by comparison with experimental results of previously tested RC column specimens at the National Research Council Canada. The results illustrate the need for refined transient strain models to assess behavior of axially loaded columns subjected to fire loadings.
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