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An anchor plate, floor plate or wall washer is a large plate or
washer Washer most commonly refers to: *Washer (hardware), a thin usually disc-shaped plate with a hole in the middle typically used with a bolt or nut *Washing machine, for cleaning clothes Washer may also refer to: *Dishwasher, a machine for cleani ...
connected to a
tie rod A tie rod or tie bar (also known as a hanger rod if vertical) is a slender structural unit used as a tie and (in most applications) capable of carrying tensile loads only. It is any rod or bar-shaped structural member designed to prevent the separa ...
or bolt. Anchor plates are used on exterior walls of
masonry Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term ''masonry'' can also refer to the units themselves. The common materials of masonry construction are bricks, building ...
buildings, for structural reinforcement against lateral bowing. Anchor plates are made of
cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...
, sometimes
wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag Inclusion (mineral), inclusions (up to 2% by weight), which give it a ...
or
steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
, and are often made in a decorative style. They are commonly found in many older cities, towns and villages in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
and in more recent cities with substantial 18th- and 19th-century brick construction, such as
New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...
,
Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...
,
St. Louis St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...
,
Cincinnati Cincinnati ( ) is a city in the U.S. state of Ohio and the county seat of Hamilton County. Settled in 1788, the city is located at the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line wit ...
, and
Charleston, South Carolina Charleston is the largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston metropolitan area. The city lies just south of the geographical midpoint o ...
; and in older
earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
-prone cities such as
San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
, as well as across all of Europe. One popular style is the ''star anchor,'' an anchor plate cast or wrought in the shape of a five-pointed star. Other names and styles of anchor plate include earthquake washer, triangular washer, S-iron, and T-head. In the United Kingdom, pattress plate is the term for circular restraints, tie bar being an alternative term for rectangular restraints.


Definition

According to the ''Oxford Dictionary of Construction, Surveying and Civil Engineering'', an anchor plate "is a plate attached to a component that enables other components to be connected to it." Although there are many types of anchors or anchorages, according to the ''Dictionary of Architecture and Construction'', an anchor plate specifically is a "wrought-iron clamp, of
Flemish Flemish (''Vlaams'') is a Low Franconian dialect cluster of the Dutch language. It is sometimes referred to as Flemish Dutch (), Belgian Dutch ( ), or Southern Dutch (). Flemish is native to Flanders, a historical region in northern Belgium; ...
origin, on the exterior side of a brick building wall that is connected to the opposite wall by a steel tie-rod to prevent the two walls from spreading apart; these clamps were often in the shape of numerals indicating the year of construction, or letters representing the owner's initials, or were simply fanciful designs." While most types of anchors are made of only steel, anchor plates might also contain malleable or cast iron. The exterior wall washer is most often made of a cast-iron star or a flat steel plate.


History of use and studies

In
Roman technology Roman technology is the collection of antiques, skills, methods, processes, and engineering practices which supported Roman civilization and made possible the expansion of the economy and military of ancient Rome (753 BC – 476 AD). The Roma ...
, wooden tie-beams (or
tie rod A tie rod or tie bar (also known as a hanger rod if vertical) is a slender structural unit used as a tie and (in most applications) capable of carrying tensile loads only. It is any rod or bar-shaped structural member designed to prevent the separa ...
s) were used between arches to negate the outward horizontal forces between them. Iron tie rods would later be used as a device to reinforce arches, vaults, and cupolas constructed across Medieval Europe. In the modern era, tie-rods are made of iron or steel, and serve to reinforce vaults, arches, and in general masonry structures.
Reinforced masonry Earthquake engineering is an Interdisciplinarity, interdisciplinary branch of engineering that designs and analyzes structures, such as buildings and bridges, with earthquakes in mind. Its overall goal is to make such structures more resistant to ...
walls are strengthened through a tie-rod that connects between parallel walls at the floor-level, which creates a horizontal compression state, thereby increasing the wall's shear strength. While the current literature is very poor, some studies have been done on analysis of anchor plates and tie-rods, for example one study dealing with concrete panels, which, although a thin veneer, may also need anchor plates to help stabilize the wall. The pressure that an anchor plate provides is constantly stiff. A study found that, as widths exceed , the advantage of having a wider plate decreased, indicating a width threshold for optimal support.


Gallery

File:Genuine barnstar.jpg, On a building in
Petaluma, California Petaluma (Miwok languages, Miwok: ''Péta Lúuma'') is a city in Sonoma County, California, Sonoma County, California, located in the North Bay (San Francisco Bay Area), North Bay region of the San Francisco Bay Area. Its population was 59,776 a ...
File:Coventry Cathedral ruins tie rods.JPG,
Tie rod A tie rod or tie bar (also known as a hanger rod if vertical) is a slender structural unit used as a tie and (in most applications) capable of carrying tensile loads only. It is any rod or bar-shaped structural member designed to prevent the separa ...
s and anchor plates in the ruins of
Coventry Cathedral The Cathedral Church of Saint Michael, commonly known as Coventry Cathedral, is the seat of the Bishop of Coventry and the Diocese of Coventry within the Church of England. The cathedral is located in Coventry, West Midlands, England. The curren ...
File:Remscheid Lennep - Stadtkirche 04 ies.jpg, Anchor plate on a church in
North Rhine-Westphalia North Rhine-Westphalia (german: Nordrhein-Westfalen, ; li, Noordrien-Wesfale ; nds, Noordrhien-Westfalen; ksh, Noodrhing-Wäßßfaale), commonly shortened to NRW (), is a States of Germany, state (''Land'') in Western Germany. With more tha ...
File:Oldendorf (Luhe) Wohlenbüttel - Wassermühle 05 ies.jpg, X-shaped wall anchor in
Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...
File:Florenz - Mauerbefestigung.jpg, Bar-style wall anchor in
Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...
File:Star in New York City Marble Cemetery (40635).jpg, A star-shaped anchor plate in
New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
File:Soulard St Louis Anchor Star.jpeg, A star-shaped anchor plate in Soulard,
St. Louis St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...
File:Cloître Saint-Trophime Anchor Plate 2.jpg, An anchor plate in the cloister of the Church of St. Trophime, Arles (France)


See also

*
Barnstar A barnstar (or barn star, primitive star, or Pennsylvania star) is a painted object or image, often in the shape of a five-pointed star but occasionally in a circular "wagon wheel" style, used to decorate a barn in some parts of the United State ...
, a purely decorative device *
Tie (cavity wall) The tie in a cavity wall is a component used to tie the internal and external walls (or leaves)—constructed of bricks or cement blocks—together, making the two parts to act as a homogeneous unit. It is placed in the cavity wall during constru ...
, used internally within cavity walls


References


External links

* {{commonscatinline, Wall anchors Architectural elements Historic preservation Structural system Visual motifs