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.What is allowable strength?

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**):