anchor plate#Gallery
{{short description|Large plate or washer connected to a tie rod or bolt}}
{{more citations needed|date=October 2010}}
File:Cloître Saint-Trophime Anchor Plate 1.jpg (France)]]
An anchor plate, floor plate or wall washer is a large plate or washer connected to a tie rod or bolt. Anchor plates are used on exterior walls of masonry buildings, for structural reinforcement against lateral bowing. Anchor plates are made of cast iron, sometimes wrought iron or steel, and are often made in a decorative style.{{cite book |title=Dictionary of Building Preservation
|last=Bucher
|first=Ward
|year=1996
|publisher=Preservation Press
|pages=576}}
They are commonly found in many older cities, towns and villages in Europe and in more recent cities with substantial 18th- and 19th-century brick construction, such as New York, Philadelphia, St. Louis, Cincinnati, and Charleston, South Carolina; and in older earthquake-prone cities such as San Francisco, 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,[http://www.stainless-uk.co.uk/product.asp?id=4 Pattress plate example] {{Webarchive|url=https://web.archive.org/web/20090726130250/http://www.stainless-uk.co.uk/product.asp?id=4 |date=2009-07-26 }} stainless-uk.co.uk 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."{{cite book |last1= Gorse |first1= Christopher |last2= Johnston |first2= David |last3=Pritchard |first3=Martin |date= 2013 |title= Oxford Dictionary of Construction, Surveying and Civil Engineering |url= http://www.oxfordreference.com/view/10.1093/acref/9780199534463.001.0001/acref-9780199534463-e-0276?rskey=TvqLAq&result=276 |publisher= Oxford University Press |page=20 |isbn= 9780199534463 }}
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 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."{{cite book |last1= Harris |first1= Cyril M. |date= 2000 |title= Dictionary of Architecture and Construction, Third Edition |publisher= McGraw Hill |pages= 31–32 |isbn= 0-07-135178-7}}
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.{{cite book |last= Kidder |first=Frank E. |date= 1913 |title= The Architect's and Builder's Handbook |url= https://babel.hathitrust.org/cgi/pt?id=nyp.33433087552133;view=1up;seq=7 |publisher= John Wiley & Sons |page= 553}}
History of use and studies
In Roman technology, wooden tie-beams (or tie rods) were used between arches to negate the outward horizontal forces between them.{{cite journal |last1= Pisani |first1= Marco Andrea |date= October 1, 2016
|title= Theoretical approach to the evaluation of the load-carrying capacity of the tie rod anchor system in a masonry wall
|journal= Engineering Structures |volume= 124 |pages= 85–95
|doi= 10.1016/j.engstruct.2016.06.015 |arxiv= 1804.08620 |bibcode= 2016EngSt.124...85P }} Iron tie rods would later be used as a device to reinforce arches, vaults, and cupolas constructed across Medieval Europe.{{Cite web|last=Petrucci|first=Enrica|title=Metal tie-rods and anchor plates in old buildings structural|url=https://www.academia.edu/14142975|via=Academia.edu}}{{Cite journal|last1=Calderini|first1=Chiara|last2=Piccardo|first2=Paolo|last3=Vecchiattini|first3=Rita|date=2019-04-03|title=Experimental Characterization of Ancient Metal Tie-Rods in Historic Masonry Buildings|url=https://www.tandfonline.com/doi/full/10.1080/15583058.2018.1563230|journal=International Journal of Architectural Heritage|language=en|volume=13|issue=3|pages=425–437|doi=10.1080/15583058.2018.1563230|s2cid=117541100 |issn=1558-3058}}
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 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.{{cite journal |last1= Shin |first1= Jiuk|last2= Kim |first2= JunHee |last3= Chang |first3= Hak-Jong
|date= January 1, 2016
|title= Anchor plate effect on the breakout capacity in tension for thin-walled concrete panels
|journal= Engineering Structures |volume= 106 |pages= 147–153
|doi= 10.1016/j.engstruct.2015.10.028 |bibcode= 2016EngSt.106..147S}}
The pressure that an anchor plate provides is constantly stiff. A study found that, as widths exceed {{convert|100|mm}}, 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
File:Coventry Cathedral ruins tie rods.JPG|Tie rods and anchor plates in the ruins of Coventry Cathedral
File:Remscheid Lennep - Stadtkirche 04 ies.jpg|Anchor plate on a church in North Rhine-Westphalia
File:Oldendorf (Luhe) Wohlenbüttel - Wassermühle 05 ies.jpg|X-shaped wall anchor in Lower Saxony
File:Florenz - Mauerbefestigung.jpg|Bar-style wall anchor in Florence
File:Star in New York City Marble Cemetery (40635).jpg|A star-shaped anchor plate in New York City
File:Soulard St Louis Anchor Star.jpeg|A star-shaped anchor plate in Soulard, St. Louis
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 purely decorative device
- Tie (cavity wall), used internally within cavity walls
References
{{reflist}}