The Romanesque bay
One bay of a Romanesque nave in section: compound piers, round arches, groin-vaulted aisles, galleries and a barrel vault braced by quadrant vaults.
The rules it illustrates
Mass resists thrust. Carry vaults on walls thick enough to absorb their thrust within their own mass; keep the windows small and set them low, below the springing of the vault, and strengthen the walls outside with shallow pilaster buttresses.
Divide the wall into bays. Run a shaft or pilaster from the floor, up the face of the pier and the wall above, to the roof or vault, so that the long nave wall is divided into a sequence of vertical bays, each containing one arch of the arcade and the windows above it.
Transverse arches beneath a barrel. Strengthen a barrel-vaulted nave with transverse arches at every bay, springing from shafts on the piers; they stiffen the vault, mark the bays and serve as ribs on which the vault can be built bay by bay.
Galleries that buttress the nave. Build galleries (tribunes) over the aisles and cover them with quarter-circle (quadrant) vaults that lean against the nave wall just below the springing of its barrel, so that the gallery vaults carry the barrel’s thrust down to the outer walls.
Where it appears in the book
In the styles Romanesque.
In the chapters Romanesque and Gothic.