Segmental arch

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A segmental arch. Segmentbage.png
A segmental arch.

A segmental arch is a type of arch with a circular arc of less than 180 degrees. [1] It is sometimes also called a scheme arch. [2]

The segmental arch is one of the strongest arches because it is able to resist thrust. [3] To prevent failure, a segmental arch must have a rise [lower-alpha 1] that is equal to at least one-eighth the width of the span. Segmental arches with a rise that is less than one-eighth of the span width must have a permanent support or frame beneath the arch to prevent failure. [3]

As far as is known, the ancient Romans were the first to develop the segmental arch. The closed-spandrel Pont-Saint-Martin bridge in the Aosta Valley in Italy dates to 25 BC. [5] The first open-spandrel segmental arch bridge is the Anji Bridge over the Xiao River in Hebei Province in China, which was built in 610 AD. [6]

Segmental arches are most commonly used in the 20th century in residential construction over doorways, fireplaces, and windows. [3]

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Anji Bridge

The Anji Bridge is the world's oldest open-spandrel segmental arch bridge of stone construction. Credited to the design of a craftsman named Li Chun, the bridge was constructed in the years 595–605 during the Sui dynasty (581–618). Located in the southern part of Hebei Province, it is the oldest standing bridge in China. It is considered one of the Four Treasures of Hebei.

Alconétar Bridge Cultural property in Garrovillas de Alconétar, Spain

The Alconétar Bridge, also known as Puente de Mantible, was a Roman segmental arch bridge in the Extremadura region, Spain. The ancient structure, which featured flattened arches with a span-to-rise ratio of 4–5:1, is one of the earliest of its kind. Due to its design, it is assumed that the bridge was erected in the early 2nd century AD by the emperors Trajan or Hadrian, possibly under the guidance of Apollodorus of Damascus, the most famous architect of the time.

Memorial Bridge (Massachusetts)

The Hampden County Memorial Bridge is a reinforced-concrete arch bridge that spans the Connecticut River between Springfield, Massachusetts and West Springfield, Massachusetts, constructed in 1922. The bridge is owned by Massachusetts Highway Department and is located on Massachusetts Route 147. It spans 209 feet (64 m) and rises 29.71 feet (9.06 m) above the river.

Pont sur la Laye

The Pont sur la Laye or Pont roman de Mane is an old stone arch bridge across the stream Laye in the French Provence close to the town Mane.

The Ponte del Gran Caso is a Roman bridge across the Torrente Gran Caso, 2 km south of Ascoli Piceno in central Italy.

Pont de Pierre (Aosta) Roman segmental arch bridge

The Pont de Pierre, meaning "Stone Bridge", is a Roman bridge in the Italian city of Aosta in the Aosta Valley. The bridge crossed the Buthier about 600 m (2,000 ft) from the eastern exit of the Roman colony Augusta Praetoria; in later times the torrente changed its course, leaving the ancient bridge today without water.

The Bridge at Nimreh is a Roman bridge in the vicinity of Shahba, Syria, dating to the 3rd or 4th century AD. Its transversal arch construction derives from old building traditions of the Hauran region and is arguably unique in Roman bridge building.

The Ponte San Lorenzo is a Roman bridge over the river Bacchiglione in Padua, Italy. Constructed between 47 and 30 BC, it is one of the very earliest segmental arched bridges in the world. It is also notable for the slenderness of its piers, unsurpassed in antiquity.

Skew arch

A skew arch is a method of construction that enables an arch bridge to span an obstacle at some angle other than a right angle. This results in the faces of the arch not being perpendicular to its abutments and its plan view being a parallelogram, rather than the rectangle that is the plan view of a regular, or "square" arch.

Bridge near Limyra

The Bridge near Limyra is a late Roman bridge in Lycia, in modern south-west Turkey, and one of the oldest segmented arch bridges in the world. Located near the ancient city of Limyra, it is the largest civil engineering structure of antiquity in the region, spanning the Alakır Çayı river over a length of 360 m (1,181.1 ft) on 26 segmental arches. These arches, with a span-to-rise ratio of 5.3:1, give the bridge an unusually flat profile, and were unsurpassed as an architectural achievement until the late Middle Ages. Today, the structure is largely buried by river sediments and surrounded by greenhouses. Despite its unique features, the bridge remains relatively unknown, and only in the 1970s did researchers from the Istanbul branch of the German Archaeological Institute carry out field examinations on the site.

Bridge near Kemer

The Bridge near Seydikemer was a Roman bridge near the ancient city of Xanthos in Lycia, in modern-day southwestern Turkey. Its remains are located on the upper reaches of the Xanthos river, 4 km upstream from the town of Seydikemer, at a site where the gravel river bed reaches a width of 500 m. Only a 29 m long and 4.5 m wide section on the right river bank, outside the inundation zone, is left today, having once served as approach to the bridge proper. Despite its near-complete destruction, the bridge represents a noteworthy example of the early use of segmental arches and hollow chambers in bridge building.

Macestus Bridge

The Macestus Bridge or Bridge of Sultançayır was a Roman bridge across the Macestus River at Balıkesir, in the northwestern part of modern-day Turkey. Its flattened arches, slender piers and the hollow chamber system documented the progress made in late antique bridge building. A first cursory investigation of the 234 m long structure was conducted in the early 20th century, but since then its existence has been largely neglected by scholars. Current photos from 2009 show that the bridge has collapsed in the meantime.

The Susegana Bridge is one of a series of Roman bridges on the Via Claudia Augusta in Susegana, northern Italy. The small structure is notable for its flattened arch, which classify it as a Roman segmental arch bridge.

Swin Bridge

Swin Bridge is the local name for a skew arch bridge in County Durham. It was built in 1830 for the Haggerleases branch of the Stockton and Darlington Railway, crossing the River Gaunless at Cockfield. It is important as an early example of the masonry arch skew bridge, and the first used to carry a railway.

References

Notes
  1. The "springing line" is the imaginary horizontal line drawn between the two points at which the arch's springer touches the impost. The "rise" is the distance from the springing line to the highest point of the "intrados" (bottom of the arch). [4]
Citations
  1. Harris, Cyril M. (1983). Illustrated Dictionary of Historic Architecture . New York: Dover Publications. p.  485. ISBN   9780486244440.
  2. Smith, Percy Major (2015). Rivington's Building Construction. Abingdon, Oxfordshire, U.K.: Routledge. p. 6. ISBN   9781317742432.
  3. 1 2 3 Kreh, Richard T. (2015). Masonry Skills. Stamford, Conn.: Cengage Learning. p. 401. ISBN   9781285426839.
  4. Auslander, Alfred (June 1910). "Lessons in Architectural Drawing for Beginners". The Building Age. p. 241. Retrieved June 4, 2017.
  5. O'Connor, Colin (1993). Roman Bridges. Cambridge, U.K.: Cambridge University Press. p. 171. ISBN   9780521393263.
  6. Temple, Robert K.G. (1986). China: Land of Discovery. Wellingborough, Northamptonshire, U.K.: Stephens. pp. 69–71. ISBN   9780850598582.