Applies separate factors to both loads (Load Factors) and material strength (Resistance Factors).
Modern, reliability-based method that uses statistical probability . Structural wood design: ASD/LRFD
Remains the historical standard for wood and is widely used due to its simplicity and the extensive existing library of hardware catalogs based on ASD. Load and Resistance Factor Design (LRFD) Applies separate factors to both loads (Load Factors)
Applies a single Factor of Safety to the material's ultimate strength to determine "allowable" stresses. Loads: Uses actual expected (unfactored) service loads. Load and Resistance Factor Design (LRFD) Applies a
Traditional, deterministic method based on elastic design .
The choice often depends on the specific project requirements or the engineer's preference: LRFD versus ASD for Wood Design
"Factored" loads increase the design burden based on the uncertainty of the load type (e.g., higher factors for live loads vs. dead loads).