Halbtonnengewölbe

Halbtonnengewölbe, also known as a half-barrel vault or tunnel vault, is a common architectural element. It is essentially a continuous, semicircular vault that spans a rectangular space. Unlike a groin vault, which is formed by the intersection of two barrel vaults, a half-barrel vault is a single, unbroken arch. This form creates a uniform, tunnel-like effect.

Historically, half-barrel vaults were frequently used in Romanesque and Gothic architecture. They provided a structural solution for roofing large, open spaces like naves, aisles, and crypts. The immense weight of these stone vaults required substantial supporting walls and piers, which contributed to the characteristic thick walls and rounded arches of Romanesque buildings.

The construction of a half-barrel vault involves laying voussoirs (wedge-shaped stones) or bricks in a curved pattern, supported by temporary centering until the keystone is placed, locking the structure into place. While strong and durable, the design places significant outward thrust on the supporting walls. This outward force necessitates strong buttressing or very thick walls to prevent collapse.

In modern construction, while less common for primary structural elements due to the efficiency of other vaulting techniques and modern materials, the aesthetic of the half-barrel vault is still appreciated and sometimes replicated in decorative contexts or for specific historical reconstructions. Its simplicity and visual continuity make it an enduring architectural feature.