A pier, in

architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings ...

, is an upright support for a structure or superstructure such as an arch or

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...

. Sections of structural walls between openings (bays) can function as piers. External or free-standing walls may have piers at the ends or on corners.

Description

The simplest cross section of the pier is square, or rectangular, but other shapes are also common. In

medieval architecture Medieval architecture is architecture common in the Middle Ages, and includes religious, civil, and military buildings. Styles include pre-Romanesque, Romanesque, and Gothic. While most of the surviving medieval architecture is to be seen in ...

, massive circular supports called drum piers,

cruciform Cruciform is a term for physical manifestations resembling a common cross or Christian cross. The label can be extended to architectural shapes, biology, art, and design. Cruciform architectural plan Christian churches are commonly describe ...

(cross-shaped) piers, and

compound pier Compound pier or cluster pier is the architectural term given to a clustered column or pier which consists of a centre mass or newel, to which engaged or semi-detached shafts have been attached, in order to perform (or to suggest the performance o ...

s are common architectural elements. Columns are a similar upright support, but stand on a round base. In buildings with a sequence of bays between piers, each opening (window or door) between two piers is considered a single bay.

Bridge piers

Poinciana Parkway RCMB bridge construction 4

Single-span

s have

abutment An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end which provide vertical and lateral support for the span, as well as acting as retaining wal ...

s at each end that support the weight of the bridge and serve as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support the ends of spans between these abutments. In cold climates, the upstream edge of a pier may include a starkwater to prevent accumulation of broken ice during peak snowmelt flows. The starkwater has a sharpened upstream edge sometimes called a ''cutwater''. The cutwater edge may be of concrete or masonry, but is often capped with a steel angle to resist abrasion and focus force at a single point to fracture floating pieces of ice striking the pier. In cold climates, the starling is typically sloped at an angle of about 45° so current pushing against the ice tends to lift the downstream edge of the ice translating horizontal force of the current to vertical force against a thinner cross-section of ice until unsupported weight of ice fractures the piece of ice allowing it to pass on either side of the pier.

Examples

In the Arc de Triomphe, Paris (''illustration, right'') the central arch and side arches are raised on four massive .

St Peter's Basilica

Donato Bramante's original plan for St Peter's Basilica in Rome has richly articulated piers. Four piers support the weight of the dome at the central crossing. 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.M. Fazio, ''Buildings Across Time'', 312 The piers of the four

apse In architecture, an apse (plural apses; from Latin 'arch, vault' from Ancient Greek 'arch'; sometimes written apsis, plural apsides) is a semicircular recess covered with a hemispherical vault or semi-dome, also known as an '' exedra''. ...

s that project from each outer wall are also strong, to withstand the outward thrust of the half-domes upon them. Many

niche Niche may refer to: Science *Developmental niche, a concept for understanding the cultural context of child development * Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ecology, the ...

s articulate the wall-spaces of the piers. MontacuteNineWorthies

References

External links