The aim of this master’s thesis was to carry out numerical simulations of the expected structural response of six large-scale concrete columns that will be tested next year in the fire furnace of the new Fire Laboratory in Logatec. The purpose of the fire tests is to assess the influence of various parameters—such as the height of the directly heated zone of the column, the magnitude and eccentricity of the applied load, and the density of transverse reinforcement—on the occurrence of explosive spalling of concrete. The numerical simulations were intended to support the planning of these tests and the selection of the most appropriate measuring equipment. The simulations were performed using the Abaqus software. First, a thermal analysis was conducted to determine the temperature profiles across the cross-sections of the specimens, followed by a mechanical analysis to evaluate load-bearing capacity, deformations, and stress states under fire exposure. The results showed that the height of the heated zone has a significant effect on the buckling mode and failure time of the columns, but a smaller influence on the stress state of the most loaded cross-section in the early stages of fire exposure, and therefore presumably also less impact on the development of potential explosive spalling. Increased eccentricity of the applied load reduces the fire resistance of the column, while denser stirrup spacing provides a slight improvement. Spalling is expected to be most pronounced in the column subjected to eccentric loading, with a distinctly asymmetric spalling pattern in that case.
|
