The Dongshuimen Bridge () and the Qiansimen Bridge (), known collectively as the Twin River Bridges, are a pair of bridges that form a road and rail connection in

Chongqing Chongqing ( or ; ; Sichuanese dialects, Sichuanese pronunciation: , Standard Mandarin pronunciation: ), Postal Romanization, alternately romanized as Chungking (), is a Direct-administered municipalities of China, municipality in Southwes ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. Consisting of two cable-stayed bridges and a tunnel across the Yuzhong peninsula where the heart of Chongqing's commercial & financial district

Jiefangbei CBD Jiefangbei CBD (), also known as Jiefangbei Business Walking Street (), is the ultra-dense, urbanized downtown core and one of several central business districts of Chongqing, China. It is anchored by a large pedestrian mall with a landmark monum ...

is located, the connection opened in 2014.

Planning

Planning for the Twin River Bridges dates to 1947, when the alignment of the connection appeared in planning documents for Chongqing.

Right of way Right of way is the legal right, established by grant from a landowner or long usage (i.e. by prescription), to pass along a specific route through property belonging to another. A similar ''right of access'' also exists on land held by a gov ...

for planned connection has been preserved since then. The plan for the crossings has always included

transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...

rail. By the time design of the Twin River Bridges began in 2008, it had been determined that the bridges could not be identical. Crossing of the

Yangtze The Yangtze or Yangzi ( or ; ) is the longest river in Asia, the third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows ...

on the south side of the Yuzhong peninsula would require a longer main span and allow for two tower in the water. A deep shipping channel in the

Jialing River The Jialing River, formerly known by numerous other names, is a major tributary of the Yangtze River in the Sichuan Basin. It is named after the Jialing Valley in Feng County, Shaanxi through which it flows. The Jialing River's most notable c ...

would not allow a second tower. The plan called for a double deck design with four vehicular lanes and pedestrian walkways on the top and two rail tracks beneath.

Design

design competition A design competition or design contest is a competition in which an entity solicits design proposals from the public for a specified purpose. Architecture An architectural design competition solicits architects to submit design proposals for a b ...

held in July 2008 sought signature long-span bridges which would complement the surrounding landscape. A team of China Merchants Chongqing Communications Research & Design Institute Co., Ltd. and

T. Y. Lin International TYLin is a global, multi-disciplinary infrastructure services firm. Headquartered in San Francisco, TYLin established its business in the design of long-span bridges and specialty structures. The firm provides a range of planning, design, const ...

, led by

Man-Chung Tang Man-Chung Tang Ph.D., P.E., Dist.M.ASCE, NAE, CorrFRSE (; born 1938) is a Chinese-born American civil engineer and businessman. Tang is chairman of the board and the technical director of T. Y. Lin International, an American design and const ...

, won the competition. The constructed design has been called visually impactful. The design team considered and ruled out several bridge types. A conventional cable-stayed bridge design was determined to require the towers to be 170 meters above the deck. The towers would have been taller than surrounding buildings when the 60-meter deck height was added. This was considered visually overpowering. The span requirements were too long for a conventional

girder bridge A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box. The term "girder" is often used interchangeably with "beam" in reference to bridge de ...

. A

suspension bridge A suspension bridge is a type of bridge in which the deck (bridge), deck is hung below suspension wire rope, cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridg ...

design would have required anchorages that interfered with the foundations of buildings along the sides of the rivers. The selected design combined cable-stayed bridges with a truss girder for both bridges. This option, called partially cable-stayed, "draws half of its support from the girders and half from a cable-stayed system that can rely on (shorter towers)."

Bridges

The Twin River Bridges have consistent design elements and were constructed in the same timeframe (opening in 2014). The bridges have two decks. The lower deck carries two railways carrying Line 6 of

Chongqing Rail Transit The Chongqing Rail Transit (branded as CRT; also known as Chongqing Metro) is the rapid transit system in the city of Chongqing, China. In operation since 2005, it serves the transportation needs of the city's main business and entertainment ...

. The upper deck carries four lanes for motor vehicles and two pedestrian walkways. The bridges are structurally a combination of a

girder A girder () is a support beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing ''flanges'' separated by a stabilizing ' ...

design and a cable-stayed design. The bridges use a box-girder cross section where the box girder is trussed in the elevation (or side) view). The box girder is tall and . The pedestrian walkways cantilever from the top of the box girder, making the top deck wide. Stay cables are in a single plane. Cables connect in the center of the top deck of the box girder. The towers are reminiscent of an ancient Chinese weaving shuttle and can also be described as needle shaped. The deck passes through the tower at its widest part, what might be considered the eye of the needle. The towers are constructed of cast-in-place concrete. The towers are 18 meters wide at the bottom, spread to a maximum width of 35 meters at the level of the upper deck, and narrow to 7 meters at the top. The water level of the rivers varies 39 meters between wet and dry seasons, controlled mainly by discharges from the Three Gorges Dam which is 570 kilometers away. At low water levels, the deck is approximately 60 meters above the water and the tower top is 100 meters above the deck.

Dongshuimen Bridge

The Dongshuimen Bridge crosses the

Yangtze River The Yangtze or Yangzi ( or ; ) is the longest list of rivers of Asia, river in Asia, the list of rivers by length, third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in th ...

with a cable-stayed main span that is long, connecting the Yuzhong and

Nan'an District Nan'an District (), is one of the six central districts of Chongqing municipality, China. It covers an area of 262.43 km2, with 44 km2 covered with forests and woods. It has an estimated population of 891,000 in late 2017. Geography The ...

s. The bridge is long, with asymmetric cable-stayed back span lengths of on the Yuzhong end and on the Nan'an end. There are nine pairs of cables connecting each tower to the deck. At the time of its opening, the length of the main span ranks the Donshuimen Bridge among the longest one hundred in the world. The substructure was built by China Railway Construction Bridge Engineering Bureau Group Co. Ltd. The superstructure was built by China Railway Eighth Civil Engineering Group Corporation (Beijing). The bridge opened to both road and rail traffic in April 2014.

Qiansimen Bridge

The Qiansimen Bridge (sometimes Qianximen Bridge) crosses the

with a cable-stayed main span that is , connecting the

Jiangbei Jiangbei () may refer to: * Henan Jiangbei Province, during the Yuan dynasty * Jiangbei District, Chongqing, China * Jiangbei District, Ningbo, Zhejiang, China * Jiangbei, Meizhou, Guangdong, China * Jiangbei (region), north of the Yangtze River ...

and the

Yuzhong District Yuzhong District () is the central district and heart of Chongqing municipality. It is the capital of the municipality and is also the political, economical, and entertainment center of the city of Chongqing. Located in the central portion of Yuz ...

s. The placement of the single tower means that the cable-stayed back span of provides a secondary channel for shipping. The bridge has a total length of as it includes girder spans of and . The bridge has nine pairs of cables. The Qiansimen Bridge has the longest stay cable of both bridges, measuring long. The bridge was shortlisted for an award by the Institution of Structural Engineers. The substructure was built by China Railway Construction Bridge Engineering Bureau Group Co. Ltd. The superstructure was built by CCCC Second Harbor Engineering Co., Ltd. The bridge opened to rail traffic in April 2014 and opened to road traffic in April 2015.

References