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Sidu River Bridge

四渡河特大桥
Sidu River Bridge; 四渡河特大桥
Coordinates	30°37′16″N 110°23′42″E / 30.62123°N 110.395088°E
Carries	G50 Shanghai–Chongqing Expressway
Crosses	Sidu River
Locale	near Yesanguan town, Badong County, Hubei, China
Characteristics
Design	Suspension bridge
Total length	1,222 m (4,009 ft)
Width	24.5 m (80 ft)
Longest span	900 m (3,000 ft)
Clearance below	496 m (1,627 ft)
History
Designer	CCCC Second Highway Consultants Co. Ltd
Opened	November 15, 2009
Location

The Sidu River Bridge (Chinese: 四渡河特大桥; pinyin: Sìdù Hé Tèdà Qiáo) is a 1,222 m-long (4,009 ft) suspension bridge crossing the valley of the Sidu River near Yesanguan in Badong County of the Hubei Province of the People's Republic of China. The bridge was designed by CCSHCC Second Highway Consultants Company, Limited. and built at a cost of 720 million yuan (approximately US$100 million).^[1]^[6] It opened to traffic on November 15, 2009.^[4]

Geography

The bridge is part of the new G50 Huyu Expressway that parallels China National Highway 318, an east-west route between Shanghai and Chongqing,^[1] crossing the wide belt of mountains that separate the Sichuan Basin from the lowlands of eastern Hubei. The Yangtze River pierces the same mountain belt 50 km (31 mi) to the north, forming the famous Three Gorges. The Yiwan Railway, completed in 2010 and running parallel to the highway, has been described as China's most difficult to build and most expensive (per km) rail line.^[7]

The bridge spans a 500-meter-deep (1,600 ft) valley of the Sidu River (a left tributary of the Qingjiang River), and superseded the Royal Gorge Bridge and the Beipan River Guanxing Highway Bridge as the highest bridge in the world until it in turn was surpassed by the Duge Bridge in 2016.

Design and construction

The bridge's design includes H-shaped towers, a truss-stiffened main span, and unsuspended side spans.^[4] The Warren-type trusses were constructed in 71 sections with the largest section weighing 91.6 metric tons (101.0 short tons). The trusses are 6.5 m (21 ft) tall and 26 meters (85 ft) wide.^[8]

The height measurement from the bottom of the gorge has been reported as 496 m (1,627 ft) by Eric Sakowski, 500 m (1,600 ft) by Chongxu Wang, and 550 m (1,800 ft) by Yinbo Liu.^{[Note 1]}^[2]^[4]^[5]

The first part of the suspension cable installed, a rope known as the pilot cable, was the first-ever to be placed using a rocket. Conditions at the bridge's location would not allow the use of boats or helicopters, which have previously been used to string the first cable. The rockets carried the pilot cables across on October 6, 2006 and resulted in time and cost savings.^[9]

The main suspension cables are made of 127 parallel wire strands bundled into a hexagonal shape (127 is the sixth centred hexagonal number). Each strand is made of 127 wires (also making a hexagonal shape so that there is a total of 16,129 wires in each of the two main suspension cables). Each cable can hold 191,960 kilonewtons (43,150,000 lb_f).^[10]

Notes

^ ^a ^b It is not clear that these sources are measuring to the same point on the bridge. Some may be measuring from the bottom of the gorge to the top of the towers, explaining some of the discrepancies in the numbers reported. In addition to the numbers reported by Sakowski, Liu, and Wang, there are additional less-reliable sources on the internet that report the height at 560 m.

References

^ ^a ^b ^c Wang 2009, p.65. "The bridge is located in central China near Yesanguan, a small town in a remote mountainous area, and serves as one of the key links in the national highway system that connects Shanghai, on the country's east coast, to Chengdu, the capital of the western province of Sichuan."
^ ^a ^b ^c ^d Wang 2009, p.64. "Stretching across a 500 m deep valley and the Sidu River in central China is a new, 1,222 m long crossing, that measured from gorge bottom to deck, may be the highest suspension bridge in the world."
^ ^a ^b Wang 2009, p.65. "The bridge features three spans measuring, from east to west, 114, 900, and 208 m. It carries two lanes in each direction and measures 24.5 m in width from curb to curb. The precast-concrete deck slopes upward from east to west at a 2.41 percent grade. The suspension cables are supported by two towers—an eastern tower measuring 118 m in height and a western tower 122 m high. The superstructure is constructed of steel."
^ ^a ^b ^c ^d ^e Sakowski.
^ ^a ^b Liu 2008. "The bridge spans over a 550 m deep valley, which is the highest suspension bridge in the world." (from the abstract in the conference program)
^ Wang 2009, p.65. "The bridge cost the Chinese government 720 million yuan (roughly U.S.$100 million). The design was engineered by CCSHCC, Second highway Consultants Company, Limited;which is based in Wuhan, China."
^ Most expensive rail line in China becomes operational, 2010-12-22
^ Wang 2009, p. 79. "A steel truss of the Warren type divided into 71 sections was used for the superstructure. The truss height is 6.5 m and the width is 26.0 m. The panel point spacing is 6.4 m, and the truss sections are connected at each panel point."
^ Wang 2009, p. 80. "The installation of the main cables began with the placement of a pilot cable." "Conventional methods for placing the pilot cable ... could not be used." "An innovative cable placement method using a military rocket was developed." "On October 9, 2006, two rockets were fired to take the two 1,300 m ropes made of chinlon, a highly elastic yarn, over the canyon, a distance of roughly 1,100 m." "The entire process was completed in a short period—perhaps 10.00 seconds—and the cost savings were significant."
^ Wang 2009, p. 79. "Prefabricated Parallel Wire Strand (PPWS) was used for the main cable. Each main cable consisted of 127 parallel wire strands arranged in a hexagonal shape, and each strand is made from 127 galvanized high-strength steel wires, each 5.1 mm in diameter, also arranged in a hexagonal shape. The maximum tension force that the cable can bear is 191,960 kN."

Sakowski, Eric. "Siduhe River Bridge" (Wiki). HighestBridges.com.
Liu, Yinbo; Chongxu Wang; Yuancheng Peng (2008). "The Construction of Sidu River Suspension Bridge". Proceedings of the 2008 International Bridge Conference (IBC 08-56). Pittsburgh: Engineers' Society of Western Pennsylvania. Archived from the original on 2009-02-15.
Wang, Chongxu; Yuancheng Peng; Yinbo Liu (January 2009). "Crossing the Limits". Civil Engineering. 79 (1). Reston, Virginia: American Society of Civil Engineers: 64–69, 79–80. ISSN 0885-7024. Archived from the original on 2010-01-15.