Constitutive Model for High Strength Concrete (HSC) at Elevated Temperatures

Abstract

Abstract---The response of concrete structures under fire is very important as fire represents as an extreme loading and severe environmental condition to a structure. The use of High Strength Concrete (HSC) in concrete construction is getting very popular now. There is an increased focus on the use of numerical methods and performance based fire design on concrete structures, which requires a temperature dependent material relationship. In this paper, a constitutive temperature dependent material model for HSC under fire is presented. Temperature dependent compressive strength, tensile strength, elastic modulus, peak strain and stress-strain relationships are discussed and identified. The model describes the variation of these properties at elevated temperatures and can be implemented into finite element software for analysis of HSC systems under fire. The proposed model is then compared with the experimental data collected and the existing models proposed by other researchers on conventional concrete and HSC. It shows close agreement with the test data and being more straightforward and simple for the numerical implementation than that of other HSC models. IndexTerms-High strength concrete, elevated temperatures, fire, constitutive model, stress-strain relationship.