stressable
Of construction materials, able to be subject to physical stress.
stressable: material that can take a load without failing
A stressable material is one engineered or naturally capable of withstanding applied loads, tension, compression, or bending forces without permanent deformation or fracture within its design limits. In construction, this quality is fundamental: concrete, steel, timber, and masonry are all stressable materials because their structural behaviour under load is predictable and quantifiable.
The term appears most often in material specifications and engineering discussions where the working stress (measured in pounds per square inch or megapascals) of a material must be established before design begins. A material is only stressable up to its yield point or elastic limit; beyond that threshold, it either yields plastically or fails catastrophically. Grade 60 reinforcing steel, for instance, is stressable to 60,000 psi in tension before plastic deformation begins.
Stressability and Safety Factor
Construction practice never uses the full stressable capacity of a material. Engineers apply a safety factor, typically ranging from 1.4 to 3.0 depending on material type and application, to ensure that actual working stresses remain well below the point of failure. A timber beam stressable to 1,200 psi in bending might be designed to carry only 400 psi under code-specified loads.
The inverse, materials that are not stressable, are brittle or friable substances like unreinforced gypsum board, unfired clay, or certain ceramics. These fail suddenly and unpredictably under tension, making them unsuitable for primary structural roles. Composite materials are engineered specifically to improve stressability in desired directions: plywood achieves greater stressability than solid wood across the grain by laminating layers at right angles.
Testing a material's stressability is routine. Tensile tests, compression tests, and bending tests determine modulus of elasticity, yield strength, and ultimate strength. These properties must be verified and documented before materials are approved for structural use in any jurisdiction with building codes.