In LRFR methodology, what does the 'resistance factor' represent?

In Load and Resistance Factor Rating (LRFR) methodology, the resistance factor (often denoted as φ) represents a reduction applied to the nominal resistance of a structural component or connection. The nominal resistance is the calculated capacity based on material properties and dimensions, assuming ideal conditions. The resistance factor accounts for uncertainties and potential variabilities in material strength, construction practices, and the accuracy of design equations. It provides a margin of safety by reducing the calculated capacity to a more conservative, reliable value. The resistance factor is always less than 1.0, and its value depends on the material, type of component, and failure mode being considered. Using a resistance factor ensures that the structure has sufficient capacity to resist applied loads with an acceptable level of safety and reliability.