Bridges Essay

This essay has a total of 537 words and 4 pages.

Bridges








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Bridges have been around sense the beginning of time. The Ancient Roman engineers used
two significant innovations, the cofferdam and cement. The cofferdam is when the put
wooden spikes in to the bottom of the river then used watertight clay over the spikes to
make a bridge. Now today there are more efficient ways to make a bridge then just out of
cement and clay. There are Suspension Bridges, Arch Bridges, Covered Bridges and many
more.

Suspension bridges have become a very common method of bridge construction in the last
century. For example the Brooklyn Bridge, George Washington Bridge, Golden Gate Bridge
and the Verrazano-Narrows Bridge. These bridges all use the conventional suspension
bridge design were large cables are suspended between towers and smaller cables are used
to hang the bridge deck from the larger cables. They now have a newer method it is where
the cables run directly down from the towers to the roadway. Construction of cable-stayed
bridges has proven to be less costly then suspension bridges. As a result, Cable-stayed
bridges are more widely used.


The Akashi-Kaikyo Bridge, connecting Kobe on the mainland with Awaji on Awaji Island, will
be a huge three-span cable-stayed bridge some 3910 meters in total length with a center
span of 1990 meters. When completed, it will be the longest bridge of its type in the
world, surpassing the Number Bridge in the UK, which has a center span of 1410 meters.
The bridge has a wind-proof and earthquake-resident construction, withstanding winds up to
80 meters per second and earthquakes reaching from 8.5 on the Richter scale. This bridge
is due to be completed in spring of 1999.


There is a suspension bridge which spans the Seine estuary in Normandy, France. The decks
of the bridge are designed as special curves so that wind flows across them as easily as
over a plane. The bridge has a central span of 2,800 feet. The span is so long that it
has been built with a slight upward curve from end to end, to accommodate the effects of
the curvature of the Earth. There are also huge cables that have to suspend the bridge in
the air.

If a bubble collides with another bubble, the result always ends up in a sharing unison.
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