Hangzhou Bay Bridge the Longest Trans-Ocean Bridge

It will not be a hyperbole to say that the rage of being a record holder in a respective field is tremendously growing day by day and encouraging people to accept the innovative ideas, techniques,and resources available in the market to fulfill their dreams. Mariya Rasheeda scans some of the distinctive bridges, that hold record in their respective field.

The construction or an infrastructure boom throughout the world has given the chance to the equipment and machinery manufacturers to understand the requirement of the builders, contractors, designers and architects, who are fully enthusiastic to present some innovative ideas, which attract the attention of the whole. To provide a shape to their visualization they look towards the manufacturers for their state-of-the-art equipment and machinery and latest technologies which reaches higher, deeper or longer as per their requirement. So it is not wrong to say that this is the brilliant opportunity for the who and who of the construction industry.

If on one hand, Burj Dubai has logged its name for being the tallest building in the world by breaking the record of Taipei, than on other hand Hangzhou Bay bridge has earned the distinction of being the longest trans-ocean bridge in the world, leaving behind Donghai Bridge in Shanghai, the previous world record holder of being the longest cross-sea bridge, completed in 2005.

Cable-stayed S-shaped Bridge

Hangzhou Bay Bridge is a cablestayed bridge across Hangzhou Bay off the eastern coast of China. It was linked up on June 14, 2007 and connects the municipalities of Shanghai and Ningbo in Zhejiang province. Construction of this bridge started in 2003. The bridge is the longest trans-oceanic bridge in the world, although it does not have the longest cable-stayed main span. The opening ceremony was held in 2007 with great domestic media publicity, though the bridge would only be used for test and evaluation purposes and not be available to ordinary public transportation. The bridge is expected to open for traffic before the 2008 olympic games. The S-shaped Hangzhou Bay Bridge will shorten the ground transportation distance from Ningbo to Shanghai by 120 km and travel time from four hours to two hours.

The Hangzhou bridge is 36 km long with six expressway lanes in two directions, making it the second-longest bridge in the world after the Lake Pontchartrain Causeway in Louisiana, USA. The bridge has two main spans, with a 448 metre northern span, and a 318 metre southern span. The designated speed is 100 kilometers per hour, and the designed longevity is more than 100 years. The total investment on the bridge is 11.8 billion yuan (US$ 1.5 billion). 35% of this amount was raised from private companies in Ningbo, 59% was provided as loans from China’s central and regional banks. Orthotropic steel deck is used on its main spans and five ramp bridges, and is to be paved with 50 mm epoxy asphalt concrete.

Service Centre

At the middle of this expressway, there is a 10,000m² service island for drivers to rest and enjoy a full range of services, including hotels, restaurants, petrol stations and a viewing tower. The island is actually a platform resting on piers, thus it will not impede the normal sea current in the Bay

Design and Structure of Bridge

In the Hangzhou Bay, one of China’s natural wonders, the Qiantang River Tide, creates fast water and large waves. The area is also a typhoon prone zone. These factors made construction feasibility a major concern for the project and the plan was only finalized after nine years of consultation and over 120 technical studies with the help of more than 700 experts throughout the world.

The cable-stayed bridge design was selected for the project as it can withstand the adverse conditions, multi-directional currents, high waves, and geologic conditions at the site. The bridge structure has also been designed to seismic criteria and will retain integrity in earthquake conditions up to seven on the Richter scale.

The 36km length will be of highway-class road with six, 3.75m lanes, three in each direction. The overall width of the bridge will be 33m. The roadway grade at crossslope will be 2% and a maximum 4% at longitudinal slope.

Designed for 100 years of service life, the bridge has speed limits of 100km/h for the main spans and 120km/h for land approaches. The bridge has a height of 62m, enabling fourth and fifth generation container ships to pass through in all conditions. The total length of cable used in the project will be 32.2km.

Bridge Layout and Structure

The Hangzhou Bay Bridge consists of nine sections. The first is the bank lead road to the north approach.The north approach rests on low piers with post-tension concrete box-girder spans spanning pre-stressed continuous concrete box-girders and drillshaft pile.

The north approach leads to the north navigable bridge; a cable-stayed bridge with twin diamond-shaped towers, double cable and steel box-girders. The main span of the north approach is 448m. Including side spans, the total length is 908m. The north high piers have continuous, 70m, post-tensioned, concrete boxgirder spans with a total length of 1,470m.

The middle bridge approach is laid on low piers with 70m, posttension, concrete box-girder spans with a total length of 9,380m. The south navigable bridge is a cable-stayed bridge with an A-shaped single tower, doublecable and steel box-girders. The main span is 318m, and the total length including side spans is 578m. The south high piers have continuous 70m, post-tension, concrete box-girder spans with a total length of 1,400m.

The eighth section measures to a total of 19,373m, and is composed of three sections:

• 6,020m in-water section with 70m girders and steel piles
• 10,100m mud-flat section with 50m girders and drill-shafts
• 3,253m land section with 30m to 80m girders and drill shaft foundations
• The ninth section is Bank Lead Road at the south approach

Other Record Holders...

The Lake Pontchartrain Causeway is the longest highway bridge over water in the entire world. The bridge is 24-miles long, and consists of two parallel decks 80- feet apart each outfitted with two lanes of traffic. The decks are supported by more than 9,000 pilings and joined by seven turn- around zones for emergency vehicles.

The original span opened to the public in 1956 as a two way, two Lane Bridge. In 1969 a second two lane span opened, substantially increasing the bridge’s safety when each span became a one way, two lane route for many commuters. Over 30,000 cars cross the Causeway Bridge each workday and the Causeway Commission is constantly striving to make the bridge safer for motorists.

Akashi-Kaikyo Bridge

The Akashi-Kaikyô Bridge also known as Pearl Bridge in Japan was completed in 1998 and is the world’s longest suspension bridge (has a record main span of 1,991 metres). The bridge links the city of Kobe on the mainland of Honshu to Iwaya on Awaji Island by crossing th Akashi Strait. The Akashi Kaikyo Suspension Bridge is the longest suspension bridge in the world and it is probably Japan’s greatest engineering feat.

It has six lanes and links the island of Awaji and the mainland city of Kobe, a distance of four miles. The concept of building a bridge across the Akashi Straits became urgent after a disaster in 1955. A ferry carrying over one hundred children sank after colliding with another ferry, in the busy shipping lane. One hundred and sixty eight children and adults died in the disaster. Political pressure for a bridge increased and in 1988 construction began.

Tatara Bridge

The Tatara Bridge was constructed in the boundary between Ehime and Hiroshima prefectures, and is a cable stayed bridge with a total length of 1480 m and a center span of 890 m which is the longest center span in the world surpassing its sister bridge, Normandy Bridge in France (total length of 2141 m and center span of 856 m). The main towers reach to a height of 220 m above sea level. The cables are placed to make a fan shape, similar to the Iguchi Bridge, and its graceful form appears like a white bird spreading its wings. The bridge, which opened on May 1, 1999, carries two lanes of traffic in both directions and has additional lanes for bicycles, motor bikes, and pedestrians.

The Tatara Bridge was originally planned as a suspension bridge in 1973. In 1989 the design was changed to a cable-stayed bridge with the same span. By building a cable-stayed bridge a large excavation for an anchorage would not be needed, thereby lessening the environmental impact on the surrounding area. The steel towers are 220 metres (722 ft) high and shaped like an inverted Y.

Construction of the bridge took a little more than six years and was accomplished without any accidents. Many technological advancements were part of the design and testing of the bridge.

Oresund Bridge

The Oresund Bridge is a combined two-track rail and four-lane road bridge across the Oresund strait. The bridge-tunnel is the longest combined road and rail bridge in Europe and connects the two metropolitan areas of the Oresund Region: the Danish capital of Copenhagen and the Swedish city of Malmö. The international European route E20 runs across the bridge and through the tunnel via the two lane motorway, as does the Oresund Railway Line. The bridge is the longest border crossing bridge in the world.

The bridge has one of the longest cable-stayed main spans in the world at 490 metres (1,608 ft). The height of the highest pillar is 204 metres (669 ft). The total length of the bridge is 7,845 metres (25,738 ft), which is approximately half the distance between the Swedish and Danish landmasses, and its weight is 82,000 metric tons.

On the bridge, the two railtracks are beneath the four road lanes. The bridge has a vertical clearance of 57 metres (187 ft), although most boat traffic across Oresund still passes over the Drogden strait (where the tunnel lies). The bridge was designed by Arup.

Donghai Bridge

Donghai Bridge is the longest cross-sea bridge in the world and the longest bridge in Asia when completed in 2005. It has a total length of 32.5 kilometres (20.2 miles) and connects Shanghai and the offshore Yangshan deep-water port in China. Most of the bridge is a low-level viaduct. There are also cable-stayed sections to allow for the passage of large ships, largest with span of 420 m. The bridge is designed for speeds upto 80 km per hour and has six traffic lanes. To provide a safer driving route in the typhoons and high waves known to hit the region, Donghai Bridge is designed in an S-shape. Its serpentine route lessens the fatigue drivers encounter when going in a straight line for long periods.

ChaoTianMen Arch Bridge

The ChaoTianMen Arch Bridge crosses the Yangtze river in the city of Chongqing in South West China. The two sides of the bridge have recently met for the first time, completing the world’s longest arch span bridge. The bridge’s main arch spans 552 m, making it 49 m longer than Sydney Harbour Bridge, on which it is modelled, and 3 m longer than the previous record holder, the Lupu Bridge in Shanghai. The bridge has been constructed by Chinese contractor 2nd Navigation Engineering Bureau.

ChaoTianMen is a double decker, with three lanes for motor traffic on the upper deck in both directions and a light railway on the lower deck. Side pedestrian lanes are provided on both decks.

ChaoTianMen arch bridge consists of 72 steel arch boxes and just two piers, which have a height of 190 m each, and was constructed by cantilevering out the side spans from each end, with temporary stay cables to support the cantilevers. Specially designed gantries were used to ‘walk’ the steel trusses and erect the steel members.

Once fabricated, the two halves of the bridge, each weighing 20,000 tonnes, had to be hydraulically tilted and steered in order to align them with the centre span.

The centre span was installed by full cantilever method with the assistance of sling pylons up to 100 m height. First the steel truss was put in place, then the arch rib truss and hangers, step by step until the centre span was closed.