What term is another name for the design method where maximum stress must be less than allowable stress under service conditions?

• A. Allowable Stress Design
• B. Loading Stress Design
• C. Working Stress Design
• D. Load Factor Design

Answer: (D)

The concept being tested is Allowable Stress Design. In this approach, the stresses produced by service (permitted) loads are compared directly to a material’s allowable stress, which is the strength divided by a factor of safety. The design requirement is that the maximum stress in a member under service conditions must not exceed this allowable stress. If the service stress stays within the limit, the member is considered safe under normal use.

This differs from design philosophies that use load factors. In methods like Load Factor Design, loads are multiplied by factors to create design loads, and the focus is on ensuring resistances meet the amplified demands rather than keeping service stresses below a fixed allowable limit. Some texts also use Working Stress Design as a term for the same idea, but the standard naming in many codes for this concept is Allowable Stress Design.