Development of Temperature and Constraint-Dependent Column Demand-Capacity Curves and Their Validation through Hybrid Fire Simulations

Abstract

The axial capacity and force demand of a steel column are expected to change continuously during a fire incident. In assessing the structural performance in the event of a fire, it is important to monitor both the capacity and force demand at the entire temperature range. Although the axial capacity of steel columns at elevated temperatures can be calculated with closed form-equations in the design codes, limited information is available regarding the changes in force demand due to the time-dependent temperature load. This paper proposes a set of demand-capacity curves for steel columns at elevated temperatures with various initial force and constraint conditions. A series of full-scale steel columns are tested using the hybrid fire simulation (HFS) method to validate the developed demand-capacity curves. The hybrid fire simulation results are also replicated numerically using a finite element model. The test results match the developed curve with minimal calibration. The developed curves can be used as a quick tool to evaluate the axial capacity and force demand of a steel column at elevated temperatures.