ABSTRACT
In North America, LSD (or, load and resistance factor design – LRFD) is based on a factored resistance approach. The general approach can be expressed as:
where: Qni = nominal (specified) load, Rn = nominal (characteristic) resistance, γi = load factor, and ϕ= resistance factor. In the North American approach, uncertainty in the calculation of the resistance side of the equation is captured by a single resistance factor while load contributions are assigned (typically) different load factors. Load factor terms have values γi ≥ 1, while the resistance term should have a value ϕ≤ 1.
