Spiral bridge

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Hastings Spiral Bridge, 1895

A spiral bridge, loop bridge, helix bridge, or pigtail bridge is a road bridge which loops over its own road, allowing the road to climb rapidly. This is useful in steep terrain, or where the approach road to a bridge would terminate too far from the bridge's end. Despite its name, the typical shape of a spiral bridge forms a helix, not a spiral.

Many multi-storey car parks feature such a design as this.

Spiral ramp to Nanpu Bridge in Shanghai, China

Pigtail bridge[edit]

A pigtail bridge on Iron Mountain Road

In the Black Hills of South Dakota, a particular form of spiral bridge, locally called a 'pigtail bridge', was introduced in 1932 by Cecil Clyde Gideon, the self-taught superintendent of Custer State Park turned highway designer. He called them “spiral-jumpoffs”. During the planning for Iron Mountain Road, there was a need to negotiate sudden elevation drops while preserving natural features for this scenic highway; the corkscrew design allowed for a spectacular—albeit expensive—solution to this problem. In order to blend the bridges with their surroundings, natural materials such as local timber were used.

Most pigtail bridges were built by the Civilian Conservation Corps in the 1930s.

List of spiral road bridges[edit]

Name Location Year Comment
A-7000 (previously C-345) Spain Málaga-Colmenar road, Spain 2 spiral tunnels at 36°46′33″N 4°22′46″W / 36.775796°N 4.379339°W / 36.775796; -4.379339
A6 Highway Italy Italy 44°19′13″N 8°22′38″E / 44.320409°N 8.377118°E / 44.320409; 8.377118
Antirio to Lamia highway (E65) Greece Greece on the climb of Mount Parnassos to Delphi, Greece. 270° spiral using an overpass.
Astoria–Megler Bridge south approach (U.S. Route 101) United States Astoria, Oregon, United States 46°11′15″N 123°51′12″W / 46.187590°N 123.853260°W / 46.187590; -123.853260
Cahill Expressway Australia Sydney, New South Wales, Australia. Spiral turns left in order to turn right.
Caiyuanba Bridge South Approach China Chongqing, China 29°32′10″N 106°33′05″E / 29.5360605°N 106.551513°E / 29.5360605; 106.551513
Canal Road Flyover Hong Kong Victoria City, Hong Kong 22°16′54″N 114°10′48″E / 22.2816003°N 114.1800447°E / 22.2816003; 114.1800447
Corkscrew Bridge, Old East Entrance Road, Yellowstone National Park (abandoned)[1] United States Wyoming, United States 1904, 1919 44°27′36″N 110°07′03″W / 44.460000°N 110.117500°W / 44.460000; -110.117500
Eastern Harbour Crossing Hong Kong Victoria City, Hong Kong 22°17′19″N 114°12′46″E / 22.2886114°N 114.2126683°E / 22.2886114; 114.2126683
G329 South Bridge Approach China Shaoxing, China 30°01′19″N 120°43′51″E / 30.0218999°N 120.7308062°E / 30.0218999; 120.7308062
G4011 Runyang Yangtze River Bridge Shiye Exit China Zhenjiang, China 32°13′12″N 119°22′06″E / 32.2201231°N 119.3682047°E / 32.2201231; 119.3682047
General Artigas Bridge Uruguay Uruguay and Argentina Argentina From Colón, Entre Ríos, Argentina to Paysandú, Paysandú Department, Uruguay, across the Uruguay river. Cantilever bridge with a spiral on the Uruguay side.
Huanggang Port Approach China Shenzhen, China
Isenfluh Switzerland Bern, Switzerland
Jialing Jiahua Bridge Approach China Chongqing, China 29°33′38″N 106°31′03″E / 29.5606004°N 106.5174331°E / 29.5606004; 106.5174331
Jinchang Road Bridge China Wuxi, China Double loop bridge on each approach 31°33′24″N 120°19′51″E / 31.556633°N 120.330889°E / 31.556633; 120.330889
Kawazu-Nanadaru Loop Bridge Japan Kawazu, Japan 1981 Double loop bridge. 34°47′28″N 138°56′17″E / 34.791°N 138.938°E / 34.791; 138.938
Lincoln Tunnel Helix
(New Jersey Route 495).
United States Weehawken, New Jersey, United States
40°46′01″N 74°01′17″W / 40.767037°N 74.021383°W / 40.767037; -74.021383
Mizukami Loop Bridge Japan Mizukami, Kumamoto, Japan 32°18′54″N 131°00′36″E / 32.315°N 131.01°E / 32.315; 131.01
N8 Bypass Brienzwiler Switzerland Switzerland 46°45′02″N 8°06′32″E / 46.750521°N 8.108833°E / 46.750521; 8.108833
Nanpu Bridge Puxi Approach China Puxi, Shanghai, China 2004
Nansha Bridge Hai'ou Exit China Guangzhou, China Interchange made of ramps from spiraling up to the Nansha Bridge. 22°53′21″N 113°32′36″E / 22.889226°N 113.543465°E / 22.889226; 113.543465
New Clear Water Bay Road Hong Kong New Kowloon, Hong Kong 22°19′54″N 114°13′29″E / 22.331717°N 114.224617°E / 22.331717; 114.224617
Prefectural Road 53 Onawaba Bridge east approach [ja] Japan Gifu, Japan 35°25′24″N 136°44′41″E / 35.423410°N 136.744817°E / 35.423410; 136.744817
Rongqiao Road Spiral Bridge China Chongqing, China Triple Loop Bridge 29°31′35″N 106°32′42″E / 29.5262731°N 106.5449174°E / 29.5262731; 106.5449174
Route de Cilaos Réunion Réunion 21°10′52″S 55°27′17″E / 21.181180°S 55.454704°E / -21.181180; 55.454704
S232 Bridge South Approach China Changzhou, China 31°42′57″N 120°04′05″E / 31.715834°N 120.068168°E / 31.715834; 120.068168
Sa Calobra Spain Majorca, Spain 39°49′55″N 2°48′57″E / 39.831968°N 2.81574°E / 39.831968; 2.81574
Sembon Matsu Bridge Approaches Japan Osaka, Japan Double loop bridge on each approach 34°37′57″N 135°28′33″E / 34.6324803°N 135.4759645°E / 34.6324803; 135.4759645
Shinkizugawao Bridge North Approach Japan Osaka, Japan
South Dakota Highway 87 in Wind Cave National Park[2] United States South Dakota, United States 1930s 43°36′04″N 103°29′40″W / 43.601215°N 103.494340°W / 43.601215; -103.494340
SP99 just north of Bolzano Italy Italy Named Schneckentunnel, German for snail tunnel
Steinmen Crossing on Oregon Highway 273, part of Historical U.S. Highway 99 through the Siskiyou Mountains United States Oregon, United States 42°05′32″N 122°35′22″W / 42.092091°N 122.589541°W / 42.092091; -122.589541
Tianmen Shan Big Gate Road, Tianmen Mountain National Park (2 bridges) China Hunan, China 29°03′15″N 110°29′00″E / 29.05424°N 110.48344°E / 29.05424; 110.48344
29°03′56″N 110°28′56″E / 29.06547°N 110.48211°E / 29.06547; 110.48211
Tianxingzhou Yangtze River Bridge Tianxingzhou Exit China Wuhan, China 30°40′28″N 114°23′16″E / 30.674541°N 114.387798°E / 30.674541; 114.387798
Thames Tunnel (planned, not constructed) England England 1825-1843 Originally planned to have an underground spiral giving access to road traffic, but this was never built.[3]
The Loop Over Bridge, on U.S. Route 441 between Gatlinburg, Tennessee, and Cherokee, North Carolina, at Bearpen Hollow in the Great Smoky Mountains National Park[4] United States Tennessee, United States[5] 35°38′06″N 83°27′58″W / 35.635036°N 83.466047°W / 35.635036; -83.466047
Three bridges on Iron Mountain Road/U.S. Route 16A United States South Dakota, United States 1930s Known locally as "pigtail bridges"
From south to north:
43°51′43″N 103°26′15″W / 43.861849°N 103.437623°W / 43.861849; -103.437623
43°52′10″N 103°26′08″W / 43.869383°N 103.435572°W / 43.869383; -103.435572
43°52′30″N 103°26′22″W / 43.874979°N 103.439530°W / 43.874979; -103.439530
U.S. Route 61 across Spiral Bridge at Hastings High Bridge United States Hastings, Minnesota, United States 1895-1951 former location: Approximately 44°44′42″N 92°51′11″W / 44.745137°N 92.853034°W / 44.745137; -92.853034
Weidun Road Bridge China Changzhou, China 31°43′22″N 120°03′35″E / 31.722803°N 120.059752°E / 31.722803; 120.059752
Wiadukt Stanisława Markiewicza Poland Warsaw, Poland 1904 In Ulica Karowa which connects Krakowskie Przedmiescie to river level,
Yanbai Yellow River Bridge North Approach China Lanzhou, China 36°04′44″N 103°52′53″E / 36.0789724°N 103.8814573°E / 36.0789724; 103.8814573
Yurikamome approach to Rainbow Bridge Japan Tokyo, Japan From the mainland.
Zhoutouju Tunnel Approach China Guangzhou, China 23°05′55″N 113°15′07″E / 23.0985181°N 113.2520531°E / 23.0985181; 113.2520531
Zuidweg Bridge Netherlands Zoetermeer, Netherlands 52°02′51″N 4°28′31″E / 52.047468°N 4.475218°E / 52.047468; 4.475218

Spiral bicycle bridges[edit]

Spiral pedestrian bridges[edit]

  • 1998–2004, Glass Spiral Bridge, Millennium Place, Coventry, England

Turnover bridges[edit]

Turnover bridges were a feature of some early British canals such as the Macclesfield. The boats were pulled by a horse, and in locations where the towpath crossed to the opposite bank, the spiral on one side allowed the horse to continue without detaching the tow rope. They were not universally provided as they were more expensive to build, needing to span both the canal and the towpath.

See also[edit]


  1. ^ Historic American Engineering Record (HAER) No. WY-86, "Corkscrew Bridge, Old East Entrance Road, Sylvan Pass, Lake, Teton County, WY"
  2. ^ Historic American Engineering Record (HAER) No. SD-54, "Pigtail Bridge, Hot Springs, Fall River County, SD"
  3. ^ J.W. Parker, The roads and railroads, vehicles, and modes of travelling, of ancient and modern countries, p. 154
  4. ^ Historic American Engineering Record (HAER) No. TN-35-Q, "The Loop Over Bridge, Gatlinburg, Sevier County, TN"
  5. ^ "Google Maps". Google Maps.

Further reading[edit]