The term for a surrounding encasement around a structural element used for confinement or protection is what?

• A. Casing
• B. Jacket
• C. Coating
• D. Sheath

Answer: (B)

A jacket is the outer protective enclosure that surrounds a structural element to provide confinement and protection. Wrapping a member with a jacket—whether steel, FRP, or concrete—helps contain the core, improve ductility and durability, and shield it from environmental damage. This concept is common in retrofits or repairs where the outer layer enhances confinement and protection around columns, beams, or pipes.

Casing is typically used for pipes or boreholes, where the primary purpose is to line or protect the interior rather than fully encase a structural element for confinement. Coating refers to a surface layer applied on the exterior, usually thinner and not intended to fully encase the member. A sheath is a protective covering associated with cables or wires rather than a structural encasement.