The allowable stress or allowable strength is the maximum stress (tensile, compressive or bending) that is allowed to be applied on a structural material. The allowable stresses are generally defined by building codes, and for steel, and aluminum is a fraction of their yield stress (strength):
What is allowable stress design?
Permissible stress design (in USA construction more commonly called allowable stress design) is a design philosophy used by civil engineers. The designer ensures that the stresses developed in a structure due to service loads do not exceed the elastic limit.
What is the difference between factored and Unfactored load?
A factored load is a load multiplied by a certain factor designated by codes of practice to drermine the strength of a structural members such as reinforced concrete. Whereas the unfactored loads are used to meet the elastic or linear limit state (below the yield limit) of structural members.