Which vault is formed by the intersection of two barrel vaults, creating a groin-like crossing?

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

Answer: (D)

When two barrel vaults intersect at right angles, their crossing creates groins—the reinforced edges where the vault surfaces meet. The resulting structure is a groin vault (or cross vault). This configuration concentrates the weight along the groins and down to four supporting piers at the corners, enabling larger bays and more efficient support.

A barrel vault is a single curved tunnel vault, so no crossing occurs. A rib vault uses a framework of ribs to shape and support the vault, typical of Gothic construction. A fan vault features radiating ribs forming a fan-like pattern. None of these describe the cross formed by the intersection of two barrel vaults.