A parametric study on concrete columns exposed to biaxial bending at elevated temperatures using a probabilistic analysis

Concrete columns exhibit a loss of both strength and stiffness during fire. The current contribution focusses on the fire performance of concrete columns subjected to biaxial bending in combination with axial loads, as such information is rarely available in literature. First, the second-order effects are quantified using a numerical tool. In Eurocode 2, the most important parameters which influence second-order effects of columns during fire are the slenderness ratio, fire duration as well as the magnitude of the axial loading. The influences of these parameters are investigated using a parametric study. Additionally, from the viewpoint of fire safety and structural reliability, uncertainties should be incorporated in the second-order analysis in order to achieve reliability-based design guidelines. Hence, the numerical tool is further developed in order to take into account uncertainties. Furthermore, the tool is validated using the Eurocode provisions and existing experimental data, while considering an ISO 834 standard fire. Finally, examples are given for the fire resistance design of concrete columns.

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