Numerical analysis of mechanical damage on concrete under high temperatures

Abstract

Concrete is a widespread material all over the world. Due to this material’s heterogeneity and structural complexity, predicting the behavior of concrete structures under extreme environmental conditions is a very challenging task. High temperatures lead to microstructural changes which affect the macrostructural performance. In this context, computational tools that allow the simulation of structures may assist the analysis, by reproducing varied situations of thermal and mechanical loading and boundary conditions. In order to contribute to this scenario, this study proposes a numerical methodology to simulate the thermomechanical behavior of concrete under temperature gradients, through inverse analyses and a user subroutine implemented in Abaqus software. Thermal loading effects were considered as loading data for a damage model. Experimental data available in the literature was adopted for adjustment and validation purposes. The preliminary results presented herein encourage further improvements so as to allow realistic simulations of such an important aspect of concrete’s behavior.

Numerical evaluation of aggregate size influence on concrete mechanical damage under high temperatures

“…Mechanical properties for the three phases are shown in Table 2. From experimental data of concrete Young's modulus for some temperatures [31], the parameters of Mazars' [19] damage model were obtained applying a method described in previous works [18] [34] and then applied to the computational sample to obtain Young's modulus for each evaluated temperature.…”

“…Schulthess et al [17] presented a method named hybrid fire testing and validated it with multiple proof-of-concept tests covering the entire temperature range relevant to structural fire engineering. Assis et al [18] applied a thermomechanical model to assess concrete mechanical damage under high temperatures using Mazars' [19] theory and experimental data for validation.…”