Nysa Bridge

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Nysa Bridge
NysaTunnel.jpg
Inside view of the "tunnel" downstream. The section in sunlight has collapsed, leaving two separate arches. The vault of the second-level arcade appears at the upper rim of the photo.
Carries Substructure for theatre square
Crosses Cakircak
Locale Nysa (Sultanhisar), Caria, Turkey
Design Arch bridge
Material Stone
Width c. 100 m
Longest span 5.7–7 m
Number of spans 1 (bottom vault)
Clearance below 5.9 m
2nd largest ancient bridge substructure
Nysa Bridge is located in Turkey
Nysa Bridge
Nysa Bridge

The Nysa Bridge is a late imperial Roman bridge over the Cakircak stream in Nysa (modern Sultanhisar) in the ancient region of Caria, modern-day Turkey. The 100 m (328 ft) long substructure was the second largest of its kind in antiquity, after the Pergamon Bridge.[1]

Dating[edit]

The Greek geographer Strabo (63 BC–AD 21), who lived in Nysa, mentioned a secret water conduit in the town, but it remains unclear whether he meant the existing tunnel-like bridge.[2] An inscription at the northern wall of the tube, close to a bend after 25 m (82 ft), indicates a construction date in late imperial times.[3] It reads "Work of Praülos until this point".[4]

Construction[edit]

The Nysa Bridge served as a substructure for the area in front of the city theatre which lay close to the Cakircak stream.[5] It was built as a two-level structure: the bottom vault spanned the brook. On top of it a row of arches connected the two hills that formed the urban area. The ground arch spanned the stream on a length of some 100 m (328 ft), giving the bridge the appearance of a tube or a tunnel, although it was constructed entirely above ground. It consists of a single, 5.7 m (19 ft) wide vault whose uphill mouth widens to 7 m (23 ft). The overall height of its semi-circular arch is 5.9 m (19 ft), featuring a rise of 2.95 m (9 ft 8 in). The vault is made of rubble stone laid in mortar, resting on a substructure of ashlar stone blocks of varying size (0.3–0.9 x 1.0–1.4 m). Originally featuring a continuous vaulting, it is collapsed today between m 75 and 85, and again at the downhill exit. The remaining, isolated structure at the downstream side has often been incorrectly referred to as a bridge of its own.[6] The Nysa Bridge was the second largest bridge substruction of its kind in antiquity, only surpassed by the nearby Bridge at Pergamon.[1] By comparison, the width of a normal, free standing Roman bridge did not exceed 10 m (33 ft).[7]

In its further course, the Cakircak also ran through the city stadion, so that naumachia could be given. There are remains of two other ancient bridges both up- and downstream.[2]

Discharge capacity[edit]

The capacity limit of the Nysa Bridge in case of floods has been the subject of hydraulic and hydrological research. The gradient of the tunnel was calculated as 3.3% with a maximum discharge capacity of 290 m³/s. Exceeding this limit puts the bridge under internal pressure and damages the structure in the process. Considering that the Cakircak is 6 km (3.7 mi) long, with a median gradient of 19% and a drainage basin of 4 km2 (1.5 sq mi), the following median intervals were calculated, depending on the method employed:

  • 17,500 years (Günerman method)
  • 10,500 years (D.S.I. method)
  • 13,000 years (Mockus method)
  • 68,000 years (Snyder method)

The study came to the conclusion that statistically every 13,500 years, a value which has been referred to as the "arithmetic mean", floods are to be expected which would exceed the capacity of the bridge.[8]

See also[edit]

References[edit]

  1. ^ a b Grewe & Özis 1994, p. 352
  2. ^ a b Grewe & Özis 1994, p. 350
  3. ^ Grewe & Özis 1994, p. 351
  4. ^ Archaiologikon Deltion 1921–22, 84: Π̣ραΰ̣λου ἔργον | ἕως ὧδε
  5. ^ Grewe & Özis 1994, p. 348f.
  6. ^ All data: Grewe & Özis 1994, p. 351
  7. ^ O’Connor 1993
  8. ^ Grewe & Özis 1994, p. 351f.

Sources[edit]

  • Grewe, Klaus; Özis, Ünal (1994), "Die antiken Flußüberbauungen von Pergamon und Nysa (Türkei)", Antike Welt 25 (4): 348–352 
  • O’Connor, Colin (1993), Roman Bridges, Cambridge University Press, ISBN 0-521-39326-4 

Further reading[edit]

  • Öziş, Ünal; Harmancioğlu, N. (1979), "Flood Flows and Capacities of the Historical Pergamon and Nysa Tunnels in Anatolia", International Association for Hydraulic Research, 18. Congress Proceedings (Cagliari) 6: 696–698 
  • Öziş, Ünal (1987), "Ancient Water Works in Anatolia", Water Resources Development 3/1: 55–62 

External links[edit]

Media related to Nysa Bridge at Wikimedia Commons

Coordinates: 37°54′12″N 28°08′44″E / 37.903405°N 28.145514°E / 37.903405; 28.145514