What is the maximum safe stress load that a structure is built to withstand called?

• A. Working stress limit
• B. Yield strength
• C. Ultimate tensile strength
• D. Modulus of elasticity

Answer: (A)

Think about how structures are kept safe under real-world loads. The maximum safe stress a structure is designed to carry is the allowable or working stress—the stress level permitted in service after applying a safety margin. This isn’t the material’s raw strength itself, but a design limit that accounts for uncertainties and ensures reliability. Yield strength is the stress where permanent deformation begins, so it’s not used as the operating limit. Ultimate tensile strength is the breaking point, which is far beyond safe operation. Modulus of elasticity measures stiffness, not how much load the structure can safely bear. So the best term for the maximum safe stress load used in design is the working stress limit.