Which vault is formed by the intersection of two barrel vaults, creating a four-way curved ceiling?

• A. Barrel Vault
• B. Rib Vault
• C. Groin Vault
• D. Fan Vault

Answer: (C)

The concept being tested is how vaults form when arches intersect. When two barrel vaults—long, rounded ceilings formed by a continuous arch—cross each other at right angles, their intersection creates a groin vault (also called a cross vault). The crossing produces four curved surface areas that meet along groins, distributing weight along these joints and allowing a larger, more open space than a single barrel vault. The other vault types don’t describe this crossing: a barrel vault is just a single curved tunnel-like ceiling, a rib vault uses a framework of ribs to support the vault, and a fan vault features radiating ribs typical of Gothic design.