WORLD'S LONGEST BRIDGE

The world's longest bridge is the Danyang–Kunshan Grand Bridge in China, part of the Beijing-Shanghai High-Speed Railway. The bridge, which opened in June 2011, spans 102.4 miles (165 kilometers). Another part of that train line, the 70.8-mile (114-km) long Langfang–Qingxian viaduct, is the second longest bridge in the world.

China constructed the Danyang–Kunshan Grand Bridge in just 4 years, employing 10,000 workers, at a cost of about $8.5 million. It crosses low rice paddies, part of the Yangtze River Delta, with just a few miles of the bridge actually crossing the open water of Yangcheng Lake in Suzhou. The bridge averages about 100 feet (31 meters) off the ground.

The world's longest road bridge is the 34-mile (55-km) long Bang Na expressway in Thailand, a six-lane elevated highway that crosses only a bit of water, the Bang Pakong River. Constructing the massive bridge required more than 1,800,000 cubic meters of concrete.

The world's longest continuous bridge over water is the Lake Pontchartrain Causeway in southern Louisiana. The causeway is actually two parallel bridges, with the longer of the two measuring 23.83 miles (38 km). The bridges are supported by 9,500 concrete pilings.

Louisiana's famous bridge faced a challenger in 2011, when China claimed that its Jiaozhou Bay Bridge was the longest spanning water. Guinness World Records decided to split the title into two parts, stating that the 26.4-mile (42.5-km) long Jiaozhou Bay Bridge is the longest bridge over water in aggregate, while the Pontchartrain is the longest continuous bridge. In Jiaozhou, land bridges and sea tunnels make up parts of the overall structure.

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GEOGRAPHIC INFORMATION SYSTEM (G.I.S)

A geographic information system (GIS) is a computer system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data. The acronym GIS is sometimes used for geographical information science or geospatial information studies to refer to the academic discipline or career of working with geographic information systems and is a large domain within the broader academic discipline of Geoinformatics.What goes beyond a GIS is a spatial data infrastructure, a concept that has no such restrictive boundaries.
In a general sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data in maps, and present the results of all these operations.Geographic information science is the science underlying geographic concepts, applications, and systems.
GIS is a broad term that can refer to a number of different technologies, processes, and methods. It is attached to many operations and has many applications related to engineering, planning, management, transport/logistics, insurance, telecommunications, and business.For that reason, GIS and location intelligence applications can be the foundation for many location-enabled services that rely on analysis and visualization.
GIS can relate unrelated information by using location as the key index variable. Locations or extents in the Earth space–time may be recorded as dates/times of occurrence, and x, y, and z coordinates representing, longitude, latitude, and elevation, respectively. All Earth-based spatial–temporal location and extent references should, ideally, be relatable to one another and ultimately to a "real" physical location or extent. This key characteristic of GIS has begun to open new avenues of scientific inquiry.

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NOTES ON PREFABRICATION

Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out.
The term prefabrication also applies to the manufacturing of things other than structures at a fixed site. It is frequently used when fabrication of a section of a machine or any movable structure is shifted from the main manufacturing site to another location, and the section is supplied assembled and ready to fit. It is not generally used to refer to electrical or electronic components of a machine, or mechanical parts such as pumps, gearboxes and compressors which are usually supplied as separate items, but to sections of the body of the machine which in the past were fabricated with the whole machine. Prefabricated parts of the body of the machine may be called 'sub-assemblies' to distinguish them from the other components.
The most widely used form of prefabrication in building and civil engineering is the use of prefabricated concrete and prefabricated steel sections in structures where a particular part or form is repeated many times. It can be difficult to construct the formwork required to mould concrete components on site, and delivering wet concrete to the site before it starts to set requires precise time management. Pouring concrete sections in a factory brings the advantages of being able to re-use moulds and the concrete can be mixed on the spot without having to be transported to and pumped wet on a congested construction site. Pre Fabricated steel sections reduces on-site cutting and welding costs as well as the associated hazards.

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