Spiral bridge

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.

Pigtail bridge

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

Name Location Year Comment A-7000 (previously C-345) Málaga–Colmenar road, Spain 2 spiral tunnels at A6 Highway Antirio to Lamia highway (E65) on the climb of Mount Parnassos to Delphi, Greece. 270° spiral using an overpass. Astoria–Megler Bridge south approach (U.S. Route 101) Astoria, United States Western terminus of US 30, a cross-country route from Atlantic City, New Jersey Cahill Expressway Sydney, Australia Spiral turns left in order to turn right.Caiyuanba Bridge South Approach Chongqing, ChinaCanal Road Flyover Victoria City, Hong Kong Corkscrew Bridge, Old East Entrance Road, Yellowstone National Park (abandoned) Wyoming, United States 1904, 1919 Eastern Harbour Crossing Victoria City, Hong KongG329 South Bridge Approach Shaoxing, ChinaG4011 Runyang Yangtze River Bridge Shiye Exit Zhenjiang, China General Artigas Bridge and From Colón, Entre Ríos, Argentina, to Paysandú, Uruguay, across the Uruguay River. Cantilever bridge with a spiral on the Uruguay side. Huanggang Port Approach Shenzhen, China Isenfluh Bern, SwitzerlandLoop entirely inside a 1.2 km tunnel Jialing Jiahua Bridge Approach Chongqing, ChinaJinchang Road Bridge Wuxi, ChinaDouble loop bridge on each approach Kawazu-Nanadaru Loop Bridge Kawazu, Japan 1981 Double loop bridge. Lincoln Tunnel Helix (New Jersey Route 495). Weehawken, United States Mizukami Loop Bridge Mizukami, Kumamoto, Japan N8 Bypass Brienzwiler Switzerland Nanpu Bridge Puxi Approach Puxi, Shanghai, China 2004 Nansha Bridge Hai'ou Exit Guangzhou, ChinaInterchange made of ramps from spiraling up to the Nansha Bridge. New Clear Water Bay Road New Kowloon, Hong Kong Gifu, JapanRongqiao Road Spiral Bridge Chongqing, ChinaTriple Loop Bridge Route de Cilaos S232 Bridge South Approach Changzhou, China Sa Calobra Mallorca, Spain Sembon Matsu Bridge Approaches Osaka, JapanDouble loop bridge on each approach Shinkizugawao Bridge North Approach Osaka, Japan The road turns 1180° (3.27 revolutions) (955° on the bridge deck + 180° on the abutment) South Dakota Highway 87 in Wind Cave National Park South Dakota, United States 1930s SP99 just north of Bolzano Two loops. One, involving a tunnel, is named Schneckentunnel, German for snail tunnel Steinmen Crossing on Oregon Highway 273, part of Historical U.S. Highway 99 through the Siskiyou Mountains Oregon, United States Tianmen Shan Big Gate Road, Tianmen Mountain National Park (2 bridges) Hunan, ChinaTianxingzhou Yangtze River Bridge Tianxingzhou Exit Wuhan, China Thames Tunnel (planned, not constructed) 1825–1843 Originally planned to have an underground spiral giving access to road traffic, but this was never built.J.W. Parker, The roads and railroads, vehicles, and modes of travelling, of ancient and modern countries, p. 154 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 Tennessee, United States Three bridges on Iron Mountain Road/U.S. Route 16A South Dakota, United States 1930s Known locally as "pigtail bridges"From south to north: U.S. Route 61 across Spiral Bridge at Hastings High Bridge Hastings, United States 1895-1951 former location: Approximately Weidun Road Bridge Changzhou, China Wiadukt Stanisława Markiewicza Warsaw, Poland 1904 In Ulica Karowa which connects Krakowskie Przedmiescie to river level, Yanbai Yellow River Bridge North Approach Lanzhou, China Yurikamome approach to Rainbow Bridge Tokyo, Japan From the mainland. Zhoutouju Tunnel Approach Guangzhou, ChinaZuidweg Bridge Zoetermeer, NetherlandsLanhai Expressway descent Lanzhou, China2023Hoàng Văn Thụ Bridge Haiphong, Vietnam2019

Spiral bicycle bridges The bridge over the mainline and narrow-gauge railways just west of Wernigerode Hauptbahnhof station in the Harz, Germany has a spiral at each end

Spiral pedestrian bridges 1998–2004, Glass Spiral Bridge, Millennium Place, Coventry, England

Turnover bridges 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.

Spiral bridge

Bron en licentie