Engineering Marvels of the World .. II

Bridges of repute – Display of amazing skills.

Construction of Bridges have been one of the major milestones in the economic development of the world and yet newer explorations for scaling the vast expanse between the remote land is an on-going process. With passage of time the skills and the techmiques changed. Listed below are a few of global acclaim.

Sydney harbour bridge (Australia)

The Sydney Harbour Bridge is the main way to cross Sydney Harbour carrying rail, vehicular, and pedestrian traffic between the Sydney central business district (CBD) and the North Shore across the Port Jackson.The bridge is locally nicknamed The Coathanger[1] because of its arch-based design, although this usage is less prevalent than it once was. The 75th anniversary of the bridge was celebrated on 18 March 2007. According to Guinness World Records, it is the widest long-span bridge in the world and is the highest steel arch bridge with the top of the bridge standing 134 metres (429.6 feet) above the harbour.[1] It is also the fourth-longest spanning-arch bridge in the world. The 49 m wide bridge was opened in March, 1932 carries 8 lanes of vehicles, 2 rail tracks, one footway for pedestrians and one lane for cyclists. The longest span (distance between the two pylons) is 503 m (1650 ft) of the total length of 1149 m (3770 ft). The bridge is held by huge hinges on the footage of the pylons on either side of the span and this attracts tourists and is considered a scenic spot for photography.

Suspension Bridges

These are bridges held by tall towers usisng strong steel cables with or without the ability to rewind /hoist. The length of main span is the most common method of comparing the sizes of suspension bridges. The length of the main span often correlates with the height of the towers and the engineering complexity involved in designing and constructing the bridge.Suspension bridges have the longest spans of any type of bridge. Cable-stayed bridges, the next longest design, are practical for spans up to around one kilometer.

The Akashi-Kaikyō Bridge ,, also known as Pearl Bridge in Japan was completed in 1998 and is the world's longest suspension bridge (measure by the length of the centre span of 1,991 metres (6,532 ft). It links the city of Kobe on the mainland of Honshū to Iwaya on Awaji Island by crossing the busy Akashi Strait. It carries the part of the Honshū-Shikoku Highway.


Donghai Bridge

Dōnghǎi Dàqiáo; literally "East Sea Grand Bridge") is the longest cross-sea bridge in the world and the longest bridge in Asia. It was completed on December 10, 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.

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