How is the fire resistance of structural steel columns protected with concrete determined according to the 2018 International Building Code?

The fire resistance of structural steel columns protected with concrete is determined using a specific formula that considers factors such as the weight of the steel column, the heated perimeter, the thickness of the concrete cover, and the thermal properties of the concrete.

According to the 2018 International Building Code, the fire resistance of structural steel columns protected with concrete is calculated using an expression that incorporates several variables. These include the average weight of the structural steel column (W), the heated perimeter (D), the thickness of the concrete cover (h), and the thermal properties of the concrete, such as its thermal conductivity (kc) and density (pc). The formula also accounts for the equilibrium moisture content of the concrete (m) and other specific heat capacities. This comprehensive approach ensures that the fire resistance rating reflects the actual performance of the column assembly under fire conditions.