Pier (architecture)

This article is about the architectural support. For other uses, see Pier (disambiguation).

Bramante's original plan for St Peter's

In architecture, a pier is an upright support for a superstructure, such as an arch or bridge. Sections of wall between openings function as piers. The simplest cross section of the pier is square, or rectangular, although other shapes are also common, such as the richly articulated piers of Donato Bramante's original plan for St Peter's Basilica (illustration, right). In medieval architecture, massive circular supports called drum piers, cruciform (cross-shaped), and composite piers are common.

The Arc de Triomphe, Paris, supported by 4 piers

In buildings that are designed as a sequence of bays, each window or door opening between piers is considered a single bay. In the Arc de Triomphe, Paris (illustration, left) the central arch and side arches are raised on four massive planar piers.

Montacute House, Somerset, c.1598. Upper eastern facade. On the external side of the piers of the long gallery are niches containing statues of the Nine Worthies. A mirror covering the internal surface is a Pier glass

3 rows of piers with arches springing from them support the Pont du Gard, Nîmes, c.19 BC

In Bramante's plan for St Peter's Basilica, the shaped piers are rendered in solid black, the vaulting they support in double lines, a familiar convention in representing architectural plans. Four piers support the weight of the dome at the central crossing; the piers of the four apses that project from each outer wall are also strong, to withstand the outward thrust of the half-domes upon them. Many niches articulate the wall-spaces of the piers. However these piers were found to be too small to support the weight and were changed later by Michelangelo to account for the massive weight of the dome.

See also

• column
• pilaster
• deep foundation