User:Acroterion/Vaulting

A sexpartite vault, in architecture, is a rib vault divided into six bays by two diagonal ribs and three transverse ribs. It is chiefly found in Gothic architecture.

The sexpartite vault provided a way to have a square vault plan without having inordinately large window bays, effectively dividing the side elevations of each vault bay into two window bays, separated by the center rib. The square plan was required if circular arches were being used with equal spring points. Due to the extent of glazing in Gothic walls, there was a structural limit to the width of a bay of windows. However, in sexpartite vaulting the ribs and vaults tended to obstruct the view of the windows from oblique angles, and the visual rhythm of large columns at the corners of the main bays and smaller columns at the window bays was considered undesirable.

Sexpartite vaults were largely superseded by quadripartite vaults, which solved the problem of bay proportions by making the vault bays rectangular, with a wide vault along the principal axis, crossed by a narrower cross vault. This plan was made possible by the use of pointed arches, whose proportions and spring points could be easily adjusted to accommodate the bay geometry. Sexpartite vaulting is regarded as a transitional form, falling out of use once the full potential of the pointed arch was developed. The elimination of the subdivided window bay allowed all columns or piers to be equal in size and appearance. The new arrangement also reduced lateral forces imparted by the vaulting.

The principal examples are those in the Abbaye-aux-Hommes and Abbaye-aux-Dames at Caen, Notre Dame de Paris, both of which used round arches, and the early Gothic cathedrals of Laon, Noyon, Notre Dame de Paris, and Sens. The sexpartite vault was brought by William of Sens to Canterbury, and it is afterwards found at Lincoln and in St Faith's Chapel, Westminster Abbey. Sexpartite vaulting is also found at Bourges and Senlis. It was revived at Beauvais Cathedral where the side aisles were converted to sexpartite vaulting when the aisle elevations were subdivided to address structural instability.