Cement mortar is utilized in the construction of brick arches. "[13], The parabolic arch employs the principle that when weight is uniformly applied to an arch, the internal compression resulting from that weight will follow a parabolic profile. While every effort has been made to follow citation style rules, there may be some discrepancies. Flat Arch4. Venetian Arch. The forms, along with the "strongly expressed ribs at the vault intersections, were dominant architectural features of Gothic cathedrals. While the form of arches changed throughout time, the idea of the arch still significantly affected other cultures. These flat arches are generally used for light loads & for spans up to 1.5 m. 2) Segmental arch:- Segmental arch is the basic type . Blind Arch. Parts of an arch | History, Types, Vaulted architecture Both the arcs join together to form a pointed edge. The rise of the arch is greater than the radius of the arc. Guide to Architectural Styles - Archisoup The shape of the arch looks like a semi-circle. A parabola is a curve that follows the path of an object thrown in the air and fallen on the ground. These three orders were adopted by the Romans in the 1st century BC. Construction of thearchesis needed where the span between the two supports issurplusand theload arrivingon the supports isheavy. In most cases they did not use mortar, relying simply on the precision of their stone dressing. The Romans, by contrast, used the semicircular arch in bridges, aqueducts, and large-scale architecture. It may also be known as a Gothic arch.Florentine ArchA Florentine arch is an arch in which intrados is semicircular in form and extrados consists of two centered pointed arch. The joints are filled appropriately with the use of cement mortar so that adequate bonding should be obtained. For example, the basilica was an indoor temple, meeting place, and court of law. Durham's cabinet pull features an appealing yet simple barrel shape that is sure to add traditional charm to your space. In such arch, the circles of two arcs meet at the top hence triangle is formed, it can be either isosceles or equilateral triangle. The Flat arch creates an equilateral triangle within Intrados as a base at an angle of 60 degrees. The intrados is similarly Flat and provided a slight increase of camber of about 10 mm to 15 mm. Center of the arc lies on the horizontal line above the vertical components where the curve starts. If vaults intersect, their intersections produce complex forms. An arch is an architectural feature that creates open space by compressing weight down and outwards. 30 Types of Architectural Arches (with Illustrated Diagrams) The Venetian arches come under the classification of four center arches which have a sum of four centers. One answer is to build a frame (historically, of wood) which exactly follows the form of the underside of the arch. When these four-centered arches are lower and depressed in form, they are called the Tudor arches. [16][17], Vaults are essentially "adjacent arches [that] are assembled side by side." The segmented arch is a type of arch in which a circular arc is less than 180 degrees. lessons in math, English, science, history, and more. A trefoil arch is also known as a three-foiled cusped arch. The Fine Axed arches are composed by establishing bricks into the desired shape. Types of Arches in Construction (13 Different Types) It is usually made by the formation of two arcs with different radius on each side. In conclusion, arches are a critical component in architecture and construction. It is a one-centered arch. There are many different types of architectural arches employed in the buildings. Romans also incorporated arches into their buildings. The arch consists of a curved structural shape that transmits loads over the opening, transmitting them over the shape of the arch to jambs, abutments, or piers on either side. succeed. The arch directs pressure downwards and outwards, creating a strong passage underneath . Ancient Romans are known to have first developed the segmental arches in bridge construction. This was extremely important in the development of Rome. Our editors will review what youve submitted and determine whether to revise the article. Romans built an arch by using two columns. A triumphal arch is constructed to commemorate an achievement and triumph. The most common kinds of true arch are the fixed arch, the two-hinged arch, and the three-hinged arch. [28], An early European example of a voussoir arch appears in the 4th century BC Greek Rhodes Footbridge.[29]. Stone Arches11. Gothic architecture, architectural style in Europe that lasted from the mid-12th century to the 16th century, particularly a style of masonry building characterized by cavernous spaces with the expanse of walls broken up by overlaid tracery. [52] The earlier uses semicircular arch, while the later contains examples of both gothic style pointed arch and semicircular arches. The Rubble arches are utilized for the formation of arches up to a span of 1 meter. An ogive is a rounded, tapered end of an object. The Arabs popularized the pointed arch, and it was in their mosques that this form first acquired its religious connotations. The Roman arch is a significant element of the architecture of Rome. In ancient Persia, the Achaemenid Empire (550 BC330 BC) built small barrel vaults (essentially a series of arches built together to form a hall) known as iwan, which became massive, monumental structures during the later Parthian Empire (247 BCAD 224). Understand the Roman arch in architecture. Another structure found in Moorish architecture is a type of fortress complex known as an alczar, . [48] Barrel vaults were also used in the Late Harappan Cemetery H culture dated 1900 BC-1300 BC which formed the roof of the metal working furnace, the discovery was made by Vats in 1940 during excavation at Harappa. Voussoirs are laid on it until the arch is complete and self-supporting. Unlike many other architectural arches, the ogee arch is purely ornamental. The voussoir that is situated in the center of the arch is called the keystone. Some blind arches were originally built as open arches and . Centre of the larger and middle curve lies below the springing line of the arch. Background: Studies based on molecular testing of oral/nasal swabs underestimate SARS-CoV-2 infection due to issues with test sensitivity, test timing and selection bias. Medieval Europe made great use of the pointed arch, which constituted a basic element in Gothic architecture. If a series of wedge-shaped blocksi.e., ones in which the upper edge is wider than the lower edgeare set flank to flank in the manner shown in the figure, the result is an arch. A segmental arch is also known as a scheme arch.Two-centered ArchA two-centered arch is an arch that consists of two arcs with their centers on the springing line of the arch. There are various types of arches including round arches, horseshoe arches, lintel arches, trefoil arches, and pointed arches. Concrete Arches. 1.1 A Brief History of Roman Architecture; . This carrying capacity stems from the fact that pressure downward on an arch has the effect of forcing the voussoirs together instead of apart. In the formation of the precast concrete blocks, the 1:2:4 ratio is utilized. Reed Hepler received an M.L.I.S. Ancient Roman Architecture | Facts, Style & Characteristics. The first known built horseshoe arches are from the Kingdom of Aksum in modern-day Ethiopia and Eritrea, dating from ca. They are, Rubble arches Rubble arches are very weak and used only for inferior work. In the case of the formation of Fine axed brick arches, the bricks are cut into wedge-shaped appropriately any three are normally utilized where the Fine work is needed. The horseshoe arches are normally utilized for architectural provisions. Thepointedarches are similarly identified as theGothic arch. The voussoirs are made of the full thickness of the arch. The Colosseum, largely built using arches, was designed by the Flavian emperors to convince the people that their emperor cared about them. In the 12th13th century, feats of engineering permitted increasingly gigantic buildings. For the construction of the gauged brick arches, skilled craftsmanship was required. 348 lessons. These are common as decorative treatments of a wall surface in many architectural styles, especially Romanesque architecture. The major purpose of the Relieving arch is to give greater strength. The techniques included indesigningandconstructingarches have since been acquired into several otherstructural forms, containingvaults,arcades, andbridges. Colosseum - This building features both rows and layers of Roman arches, which are supported by foundations that run between the layers. Central points of the smaller arcs at the ends lie on the springing line. A horseshoe arch is also commonly known as a Moorish arch and sometimes as a keyhole arch due to its resemblance to a keyhole. 12.Florentine Arches: The masonry arch is one of the oldest structural elements. It may also be known as a Gothic arch. Stained-glass window panels rendered startling sun-dappled interior effects. Vault Architecture Development & Types | What is Vaulting in Architecture? [10], The most common kinds of true arch are the fixed arch, the two-hinged arch, and the three-hinged arch. It is also known as a discharging arch. They also introduced the triumphal arch as a military monument. Vaults began to be used for roofing large interior spaces such as halls and temples, a function that was also assumed by domed structures from the 1st century BC onwards. In a flat arch, intrados behaves as the base of an equilateral triangle that is made by skewbacks placed at an angle of 60 degrees. A blind arch is an arch infilled with solid construction so it cannot function as a window, door, or passageway. It forms the shape of an inverted V alphabet. Parabolic arches have widely used in the construction of bridges and other engineering discoveries in the ancient world. Actually, the arch is one of the single most important architectural discoveries in human history, and we have the Romans to thank for it. The arch formed the basis for the evolution of the vault. Pointed Shape Arch2. For the formation of the arches, the stones are cut into an adequate shape and dressed suitably. These types of spans are formulated of rubber stones that are hammered and dressed appropriately. During construction of an arch, the voussoirs require support from below until the keystone has been set in place; this support usually takes the form of temporary wooden centring. Create your account, 22 chapters | After all, they're pretty much everywhere these days, from bridges to fast food logos. This type of arch is created above the Flat arch or on a wooden lintel. The three main types of Moorish architectural arches are the horseshoe arch, the polylobed . Arches were known in ancient Egypt and Greece but were considered unsuitable for monumental architecture and seldom used. These arches are used for a small span of up to. In the case of relieving arch, we can replace the decayed wooden lintel easily without disturbing the stability of the structure. Of all forms of arch, the parabolic arch produces the most thrust at the base yet can span the greatest distances. It's okay, we all do. Throughout the Roman empire, their engineers erected arch structures such as bridges, aqueducts, and gates. It is best known for its large religious temples built in stone, designed from principles of order . This spectacle was a massive parade, and the triumphal arch, decorated with carvings of the emperor's victory, was one of the most important pieces. 21 Different Types of Arches Construction - CivilJungle The segmental arch is one of the toughest arches which has a decent capacity to withstand thrust. In masonry construction, arches have several great advantages over horizontal beams, or lintels. Being the shape of the curve that a loose span of chain or rope traces, the catenary is the structurally ideal shape for a freestanding arch of constant thickness. Various Types of Arches differently classified are listed Below,1. Basic Construction of Arches. The external thrust put out by an arch at its floor must be restricted either by the weight of supporting walls or weight, by foundations, or by a contradicting tie between the two sides. In the semi-circular arch, the thrust transmitted to the abutment is completely in a vertical direction. Tracery is a type of ornamentation around the frame of a doorway, arch, or window, in which interlocking bands constitute the main decorations. These are roughly shaped and sized. In the late Middle Ages the segmental arch was introduced. The Monolithic concrete arches were initially utilized for longer spans. It is also known as an acute arch or an ogive arch. Concrete Arches13. A four-centred arch is a low, wide type of arch with a pointed apex. Pointed arch - Wikipedia Longest span: 279.9 m (977.5 feet). The downward pressure on the arch possesses the impact of forcing the voussoirs together instead of apart. A flat arch is generally the weakest arch. The Roman Forum Map & Facts | What is the Roman Forum? Material selection, proper In this type of arch, a rise should be equal to a minimum of one eighth of the width of the arch in order to efficiently endure thrust. It is a type of an elliptical arch. [20] Rare exceptions are an arched mudbrick home doorway dated to circa 2000BC from Tell Taya in Iraq[21] and two Bronze Age arched Canaanite city gates, one at Ashkelon (dated to c. 1850 BC),[22] and one at Tel Dan (dated to c. 1750 BC), both in modern-day Israel. Grew this Professional Architectural Firm from 1 to 7 employees, served as Architect-Of-Record for projects with construction values from $5,000 to over $400-million, both new and renovation, with . Two courses of rings in header and stretcher form. The Roman arch is one of the most iconic aspects of Roman architecture. Types of Arches Construction based on Shape, Material, Workmanship Arches are valued for their strength, versatility, and aesthetic appeal, and continue to be a widely used feature in contemporary architecture. This Jeffrey Alexander pull is available in four standard pull lengths, 12" appliance handle and coordinating ringed mushroom knob. It may be either isosceles or equilateral. The one-centered type of arches has simply one special center. The semicircular arch can be flattened to make an elliptical arch, as in the Ponte Santa Trinita. [58], Depressed Tudor arch on Layer Marney Tower in Essex, England, Blind arches on the Church of San Tirso in Sahagn, Len, Spain, Washington Square Arch, a triumphal arch in Greenwich Village, Manhattan, New York City, Delicate Arch, a natural arch in Arches National Park near Moab, Utah, A rock balance sculpture in the form of an arch, Medial longitudinal arch of the human foot (Gray's Anatomy), Restored Canaanite city gate of Ashkelon, Ashkelon, Israel (2014), Reconstructed Ishtar Gate of Babylon in the Pergamon Museum, Berlin (2014), Taq Kasra (Archway of Ctesiphon), Salman Pak, Iraq (1864), Arch of Augustus, Rimini, Emilia-Romagna, Italy (2015), Arch of Constantine, Rome, commemorating a victory by Constantine I in 312 AD (2007), The Arc de Triomphe, Paris; a 19th-century triumphal arch modelled on the classical Roman design (1998), Soldiers' and Sailors' Arch in the Grand Army Plaza, Brooklyn, New York City (2007), Gateway Arch in St. Louis, Missouri; a monument based on a catenary arch (2011), The Theme Building at Los Angeles International Airport, California, Pont Flavien over the River Touloubre in Saint-Chamas, Bouches-du-Rhne, France (2008), Old stone bridge in Kerava, Finland (2011), Bridge of Seonamsa Temple, Suncheon, South Jeolla Province, South Korea (1979), Grosvenor Bridge over the River Dee in Chester, Cheshire, England, UK (2007), Union Arch Bridge carrying the Washington Aqueduct and MacArthur Boulevard (formerly named Conduit Road) in Cabin John, Montgomery County, Maryland (2008), Anji Bridge over the Xiaohe River, Hebei Province, China (2007), The dry stone bridge, so called Porta Rosa (4th century BC), in Elea, Province of Salerno, Campania, Italy (2005), Pont du Gard, a Roman aqueduct in Vers-Pont-du-Gard, Gard, France (2014), Bridge in esk Krumlov, Czech Republic (2004), Rialto Bridge over the Grand Canal in Venice, Italy (2011), Pont de Bercy over the River Seine, Paris, carrying the Paris Mtro on its upper deck and a boulevard extension on its lower deck (2006), Arlington Memorial Bridge over the Potomac River in Washington, D.C. (2007), Francis Scott Key Bridge over the Potomac River in Washington, D.C. (2006), Woodrow Wilson Memorial Bridge carrying Interstate 95 (I-95) and the Capital Beltway over the Potomac River between Alexandria, Virginia and Oxon Hill, Maryland (2007), Arrbida Bridge over the Douro River connecting Porto, and Vila Nova de Gaia, in the Norte Region, Portugal (2011), Rainbow Bridge over the Niagara River connecting Niagara Falls, New York and Niagara Falls, Ontario, Canada (2012), Tyne Bridge over the River Tyne, Newcastle upon Tyne, England, UK (2004), Hell Gate Bridge over the East River, New York City, Sydney Harbour Bridge, Sydney, New South Wales, Australia (2010), Ludendorff Bridge over the Rhine River, Remagen, Germany, showing damage before collapse during the Battle of Remagen in World War II (1945), Lianxiang bridge over the Xiang River, Xiangtan, Hunan Province, China (2007), Zhivopisny Bridge over the Moskva River, Moscow, Russia (2009), Margaret Hunt Hill Bridge over the Trinity River in Dallas, Texas (2012), Juscelino Kubitschek Bridge crossing Parano Lake, Braslia, Brazil (2007), Gateshead Millennium Bridge over the River Tyne, Newcastle upon Tyne, England, UK (2005), Arch supporting the Eiffel Tower, Paris (2015), The second Wembley Stadium in London, built in 2007 (2007), The first San Mams Stadium, in Bilbao, arch built in 1953, demolished 2013 (2013), St Pancras railway station, London (2011), Train shed in St Pancras railway station, London (2010), Train shed in Victoria Station, London (2006), Lucerne railway station, Switzerland (2010), Central railway station, Frankfurt, Germany (2008), Train shed in Central railway station, Frankfurt, Germany (2005), Arches in Main Concourse, Grand Central Terminal, Manhattan, New York City (2014), Interior arches in Washington Union Station, Washington, D.C. (2006), Arches in Great Hall, Chicago Union Station, Chicago, Illinois (2010), Haus der Kulturen der Welt, Berlin, Germany (2011), Stonework arches seen in a ruined stonework building Burg Lippspringe, Germany (2005), Arches in the Casa-Museo del Libertador Simn Bolvar in Havana, Cuba (2006)[59], Arches in dining hall at Kings College, University of Cambridge, Cambridge, England (2007), Arches inside Annenberg Hall, Memorial Hall, Harvard University, Cambridge, Massachusetts (2016), Healy Hall, Georgetown University, Washington, D.C. (2009), Arches in throne room of Neuschwanstein Castle, Bavaria, Germany (1886 photochrom print), Arches in the Court of the Lions, Alhambra, Granada, Andalusia, Spain (2012), External arches in the Court of the Myrtles, Alhambra, Granada, Andalusia, Spain (2009), Arches inside the North Gallery, Court of the Myrtles, Alhambra, Granada, Andalusia, Spain (2010), Arches in the nave of the church in monastery of Alcobaa, Portugal (2008), North facade of Chartres Cathedral, Chartres, France (2008), Arches in choir of Chartres Cathedral, Chartres, France (2013), Arches in nave of Westminster Abbey, City of Westminster, London (2006), Arches inside the Washington National Cathedral, Washington, D.C. (2005), Interior arches in St. Peter's Basilica, Vatican City (2009), Arches inside the Hagia Sophia in Istanbul, Turkey (1983), Arches inside the western upper gallery, Hagia Sophia, Istanbul, Turkey (2007), Interior arches in the Masjid al-Haram, Mecca, Saudi Arabia (2008), Roof of Masjid al-Haram, Mecca, Saudi Arabia (2008), Dome of the Rock, Old City of Jerusalem (2010), Arches inside the Dome of the Rock, Old City of Jerusalem (2014), Arches in the Shahi Mosque, Chitral, Khyber Pakhtunkhwa province, Pakistan (2016), Taj Mahal in Agra, Uttar Pradesh, India (2009), The Great Gate (Darwaza-i-rauza): Entrance to grounds of Taj Mahal, Agra, Uttar Pradesh, India (2004), Arches inside the Taj Majal, Agra, Uttar Pradesh, India, Arches in Main Reading Room, Thomas Jefferson Building, Library of Congress, Washington, D.C. (2009), Arches in Great Hall, Thomas Jefferson Building, Library of Congress, Washington, D.C. (2007), Art Deco arches on Chrysler Building, Manhattan, New York City (2005), New York Public Library Main Branch, Manhattan, New York City (2016), Arches inside the entrance of New York Public Library Main Branch, Manhattan, New York City (2012), Arches in Great Hall, Metropolitan Museum of Art, Manhattan, New York City (2012), Arches in Sculpture Gallery, West Building, National Gallery of Art, Washington, D.C. (2007), Arches inside the Legion of Honor, Lincoln Park, San Francisco, California (2010), Arches near the Jordan Staircase, Winter Palace, Hermitage Museum, St. Petersburg, Russia (2015), Arches in Pavilion Hall, Small Hermitage, Hermitage Museum, St. Petersburg, Russia (2015), Arches in Salle du Mange, Louvre Palace, Paris (2007), Arches in Galerie des Batailles, Palace of Versailles, Versailles, Yvelines, France (2013), Arches in Hall of Mirrors, Palace of Versailles, Versailles, Yvelines, France (2011), Arches in Westminster Hall, Palace of Westminster, City of Westminster, London (2011), Arches in St. Stevens Hall, Palace of Westminster, City of Westminster, London (2007), Horseshoe arch inside the Aljafera Palace, Zaragoza, Spain (2004), Multifoil arches inside the Aljafera Palace, Zaragoza, Spain (2004), Catenary arches inside the Casa Mil in Barcelona, Spain by Antoni Gaud (2010}, Rajasthani style arches inside the 16th-century City Palace, Udaipur, India (2013), Main faade of the Itamaraty Palace in Braslia, Brazil, decorated with many arches (2005), Arches inside the National Building Museum (formerly Pension Building), Washington, D.C. (2007), Front entrance of the Old Post Office Building in Washington, D.C. (2006), Arches inside the Old Post Office Building in Washington, D.C. (2009), Bankstown Reservoir, Bankstown, Sydney, New South Wales, Australia (2018), Crypt of the Popes in the Catacomb of Callixtus, Rome (2007), Chinese Eastern Han Dynasty (25220 AD) tomb chamber, Luoyang (2008), Entrance to Washington family tomb at Mount Vernon, Fairfax County, Virginia (2014), Natural Bridge in Rockbridge County, Virginia (2014), Jiangzhou Natural Bridge, Guangxi Zhuang Autonomous Region, China (2012), Landscape Arch, Arches National Park, Utah (2016), Double O Arch, Arches National Park, Utah (2007), Aloba Arch, Ennedi-Est Region, Chad (2015), Shipton's Arch, Xinjiang Uygur Autonomous Region, China (2011), Darwin's Arch, Galpagos Archipelago, Pacific Ocean (2006), Shah Abbas Arch Dam (Tagh E Shah Abbas), Tabas County, South Khorasan Province, Iran (2011), Hoover Dam in the Black Canyon of the Colorado River, Clark County, Nevada and Mohave County, Arizona (2017), El Atazar Dam on the Lozoya River near Madrid, Spain (2014), This article is about the architectural construct. An arch is an architectural form that controls the pressure from the weight of a building in a specific way. It is a semi-circular arch that diverts pressure, through use of a keystone, down into the ground. Brick arches are one of the popular types of arches that are utilized in construction. In 2010, a robot discovered a long arch-roofed passageway underneath the Pyramid of Quetzalcoatl, which stands in the ancient city of Teotihuacan north of Mexico City, dated to around 200AD. Joints radiate from the centre of the arch, which lies below the springing line. It is considered to be one of the strongest and most durable arches as these arches have the ability to resist force. Arches are self-supporting, balanced by the force of gravity conducting on their weight to carry them in compression. Types of Arches based on Workmanship and Construction Materials Based on material used for construction and workmanship, arches may be classified as: 1. Pointed or Gothic Arch. copyright 2003-2023 Study.com. This is the basic type of arch used for buildings in which the Centre of the arch lies below the springing line. Each type of arch has unique characteristics and is used in specific architectural styles. What is an Arch? Different Components of an Arch - The Constructor Monolithic concrete block arches are suitable for larger spans. It is commonly used in bridges, where long spans are needed.[13]. Parabolic arches were introduced in construction by the Spanish architect Antoni Gaud, who admired the structural system of the Gothic style, but for the buttresses, which he termed "architectural crutches". Types of Arches | Architectural Details | Architecture Student Chronicles A point forms at the apex of the arch. View more property details, sales history and Zestimate data on Zillow. Cinquefoil ArchPointed cinquefoil arch is an arch with the intrados outline created by five rings overlapping each other. Kitchen Inventions Durham 3" Center to Center Arch Pull | Wayfair Segmental in shape and provided over the openings . These stones are joined together using cement mortar. in Roman aqueducts. The Flat arch is normally utilized for the construction of light-load structures. An arch is a pure compression form. The pointed shape arch carries two arcs of the circle which fulfills at theapexandsets a triangle.Triangle elementsmay be equilateral or isosceles (similarly recognized asLancet Arch). Thus, the complete surface of this type of arch provides an extremely aesthetical appearance. New Schaff-Herzog Encyclopedia of Religious Knowledge, Vol. For the flat arch, the intrados is flat and it acts as a base of an equilateral triangle which was formed by the horizontal angle of, Even though the intrados is flat but it is given that a slight rise of camber of about, Extrados is also horizontal and flat. Arches were known in ancient Egypt and Greece but were considered unsuitable for monumental architecture and seldom used. Arch Types & Examples in Architecture | What is a Pointed Arch in Architecture? The formation of the gauged brick arches needed experienced workmanship for its construction. Read More: Refractory Bricks | Fire Bricks | Types of Refractory Bricks. Ogee Arch: Types & Examples. While these cultures had the arch, they rarely used it except for underground tunnels and drainage systems, where the force of the earth around it provided natural buttressing, or reinforcement. The external thrust rises as the height, or rise, of the arch declines. There is another type of rampant arch that is round rampant arch. In ancient China, most architecture was wooden, including the few known arch bridges from literature and one artistic depiction in stone-carved relief. The brick arches are subdivided into three types. It is also known as the half-through arch bridge. Monolithic concrete block arches are generally formed from cast-in-situ concrete, either plain or reinforced. Parabolic ArchA parabolic arch is an arch that takes the form of a parabola. 13 Types of Arches Construction, Shape, and Material - Civil Knowledges Cementmortaris utilized in the construction of brick arches. A skewback is a masonry course with an inclined surface supporting the ends of an arch. Width of the lancet arch is narrower than the height. Forms of arch displayed chronologically, roughly in chronological order of development: Shouldered flat arch (see also jack arch). The center of the stilted arches on a straight line. Segmental Arch5. American architect Eero Saarinen designed it in 1947 in the shape of a weighted catenary arch. A semicircular arch having its extrados struck from a higher point than its intrados so that the length of the voussoirs is longer nearer the top of the arch. A series of rounded arches side by side is called an arcade. Admit it, you take arches for granted. An Equilateral Arch possesses a two-center. [54], Since it is a pure compression form, the arch is useful because many building materials, including stone and unreinforced concrete, can resist compression, but are weak when tensile stress is applied to them (ref: similar to the AL-Karparo [8:04]).[55].