Spiral bridge


A spiral bridge, loop 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. The shape of the bridge forms a helix, not a spiral.
Many multi-storey car parks feature such a design as this.
in Shanghai, China

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

NameLocationYearComment
Spiral Bridge at Hastings High Bridge Hastings, Minnesota, United States1895-1951
South Dakota Highway 87 in Wind Cave National Park South Dakota, United States
Steinmen Crossing on Oregon Highway 273, part of Historical U.S. Highway 99 through the Siskiyou Mountains. Oregon, United States
A bridge on US 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 South Dakota, United States1930s
Lincoln Tunnel approach road to west portal. Weehawken, New Jersey, United States
Astoria–Megler Bridge south approach. Oregon, United States
Zuidweg Bridge Zoetermeer, Netherlands
General Artigas Bridge Uruguay and ArgentinaFrom Colón, Entre Ríos, Argentina to Paysandú, Paysandú Department, Uruguay, across the Uruguay river. Cantilever bridge with a spiral on the Uruguay side.
Wiadukt Stanisława Markiewicza Warsaw, Poland1904In Ulica Karowa which connects Krakowskie Przedmiescie to river level,
A-7000 Málaga-Colmenar road, Spain2 spiral tunnels at
Thames Tunnel England1825-1843Originally planned to have an underground spiral giving access to road traffic, but this was never built.
Route de Cilaos France
Sa Calobra Majorca, Spain
N8 Bypass Brienzwiler Switzerland
Isenfluh Switzerland
A6 Highway Italy
SP99 just north of Bolzano ItalyNamed Schneckentunnel, German for snail tunnel
Greeceon the climb of Mount Parnassos to Delphi, Greece. 270° spiral using an overpass.-
S232 Bridge South Approach Changzhou, China
Weidun Road Bridge Changzhou, China
Caiyuanba Bridge South Approach Chongqing, China
Rongqiao Road Spiral Bridge Chongqing, ChinaTriple Loop Bridge
Jialing Jiahua Bridge Approach Chongqing, China
Zhoutouju Tunnel Approach Guangzhou, China
New Clear Water Bay Road Hong Kong, China
Yanbai Yellow River Bridge North Approach Lanzhou, China
Nanpu Bridge Puxi Approach Puxi, Shanghai, China2004
G329 South Bridge Approach Shaoxing, China
Huanggang Port Approach Shenzhen, China
Jinchang Road Bridge Wuxi, ChinaDouble loop bridge on each approach
Sendonmatsuo Bridge Approaches Osaka, JapanDouble loop bridge on each approach
Shinkizugawao Bridge North Approach Osaka, Japan
Gifu, Japan
Kawazu, Japan1981Double loop bridge.
Mizukami Loop Bridge Mizukami, Kumamoto, Japan
Yurikamome approach to Rainbow Bridge Tokyo, JapanFrom the mainland.
Cahill Expressway Sydney, New South Wales, Australia.Spiral turns left in order to turn right.

Spiral pedestrian 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.