Page 486 - (DK) The Ultimate Visual Dictionary 2nd Ed.

ARCHITECTURE
PARTS OF AN ARCH
Arches and vaults Voussoir Keystone Crown Abutment

Keystone
ARCHES ARE CURVED STRUCTURES used to bridge spans
and to support the weight of upper parts of buildings, Extrados
such as domes, as in St. Paul’s Cathedral (below) and Abutment Haunch
Intrados
the antique temple (opposite). The voussoirs (wedge- (soffit)
shaped blocks) that form an arch (right) support Impost Intrados
Springing (soffit)
each other and convert the downward force of the point
Abutment
weight of the building into an outward force. This
outward force is in turn transferred to buttresses, piers, Span Abutment
or abutments. A vault is an arched roof or ceiling. There are four FRONT SIDE
main types of vault (opposite). A barrel vault is a single vault, semicircular
in cross-section; a groin vault consists of two barrel vaults intersecting at
Inner
right-angles; a rib vault is a groin vault reinforced by ribs; and a fan dome Colonnade
vault is a rib vault in which the ribs radiate from the springing
Pilaster Passageway
point (where the arch begins) like a fan.
Base Cornice
ARCHES AND BASE OF
DOME, ST. PAUL’S Pendentive Opening to Pedestal of
CATHEDRAL, LONDON, passageway outer dome
BRITAIN, 1675-1710
(BY C. WREN) “Whispering Gallery”
Upper arch Triangular
(concealing buttress
difference in
heights between Molded
main arch and bracket
minor arches) Round
arch Semidome
Extrados
Upper barrel -
Intrados (soffit) vaulted passage
opening on to
Springing point side aisle
Barrel vault
Impost
Abutment

Strut built into
Passage leading masonry to
to side aisle
strengthen pier
(added in the
20th century)
Minor arch Main arch Pier
leading to leading to Minor
side aisle nave
arch
TYPES OF ARCH

HORSESHOE ARCH (MOORISH BASKET ARCH (SEMI-ELLIPTICAL TUDOR ARCH, TOWER LANCET ARCH, TREFOIL ARCH, BEVERLEY
ARCH), GREAT MOSQUE, ARCH), PALATINE CHAPEL, AIX- OF LONDON, BRITAIN, WESTMINSTER ABBEY, MINSTER, YORKSHIRE,
CORDORA, SPAIN, 785 LA-CHAPELLE, FRANCE, 790-798 c.1086-1097 LONDON, BRITAIN, 1503-1519 BRITAIN, c.1300

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