Suspension bridges in their simplest form were originally made from rope and wood.
Modern suspension bridges use a box section roadway supported by high tensile strength cables.
In the early nineteenth century, suspension bridges used iron chains for cables. The high tensile cables used in most modern suspension bridges were introduced in the late nineteenth century.
Today, the cables are made of thousands of individual steel wires bound tightly together. Steel, which is very strong under tension, is an ideal material for cables; a single steel wire, only 0.1 inch thick, can support over half a ton without breaking.
(http://www.design-technology.org/suspensionbridges.htm)
Light, and strong, suspension bridges can span distances from 2,000 to 7,000 feet far longer than any other kind of bridge. They are ideal for covering busy waterways.
With any bridge project the choice of materials and form usually comes down to cost.
Suspension bridges tend to be the most expensive to build. A suspension bridge suspends the roadway from huge main cables, which extend from one end of the bridge to the other. These cables rest on top of high towers and have to be securely anchored into the bank at either end of the bridge.
The towers enable the main cables to be draped over long distances. Most of the weight or load of the bridge is transferred by the cables to the anchorage systems. These are imbedded in either solid rock or huge concrete blocks. Inside the anchorages, the cables are spread over a large area to evenly distribute the load and to prevent the cables from breaking free.
Structural Failure
Some bridges have in the past suffered from structural failure. This may be combination of poor design and severe weather conditions.
When it was opened in 1940, the Tacoma Narrows Bridge was the third longest suspension bridge in the world. It later become known as "Galloping Gertie," due to the fact that it moved not only from side to side but up and down in the wind. Attempts were made to stabilize the structure with cables and hydraulic buffers, but they were unsuccessful.
Eventually on November 7, 1940, only four months after it was built the bridge collapsed in a wind of 42 mph. The bridge was designed to withstand winds of up to 120 mph.
Some experts have blamed the collapse of the bridge upon a phenomenon called resonance. When a body vibrates at its natural frequency it can shatter. Resonance is the same force that can shatter a glass when exposed to sound vibrations from an opera singers voice.
Today all new bridges prototypes have to be tested in a wind tunnel before being constructed. The Tacoma Narrows bridge was rebuilt in 1949.
Kisah-kisah dan teropongan seorang siamang profesional di Bukit Antarabangsa, Ampang, Selangor. Bukit Antarabangsa adalah kawasan berbukit ramai golongan artis dan professional tinggal. Blog ini kini mesra waktu pejabat. Sifat siamang adalah untuk melolong apa berita yang baik dan buruk di terima. Klik control play untuk mendengar lolongannya.
Bebel Without a Clause
Tuesday, October 27, 2009
Sunday, October 25, 2009
Nik Aziz is politically senile And should go!
Nik aziz had exceeded the kind invitation of PAS and should relinquish his post or be sacked from the party while having the ability to
Predict those who or won't go to heaven, he has now exceeded his stay as murshidul am pas a post of nomination not electoral. He should be islamic enough to resign
His. Current post and Compete for the top post. Hadi is elected by members And therefore cannot be chalenged. NA can be said as nyanyuk politic or politicslly senile which is. Bad for the party and the well being of state of kelantan.
Predict those who or won't go to heaven, he has now exceeded his stay as murshidul am pas a post of nomination not electoral. He should be islamic enough to resign
His. Current post and Compete for the top post. Hadi is elected by members And therefore cannot be chalenged. NA can be said as nyanyuk politic or politicslly senile which is. Bad for the party and the well being of state of kelantan.
Saturday, October 24, 2009
Petir di bukit antarabangsa getir di PAS. Bapa Perpecahan Islam tempelakkan Hadi Dan Nash .
Terkejut besar teman hari ini. Bukan2 bukan itu yang membuat teman terkejut dari hibernasi teman banyak minggu. Kebakaran akibat petir di blkg Lamam Oakleaf sudahpun reda. Ada dari pusat khidmat panggil 999 sekali lagi. Walaupun hujan lebat api makin merebak. Alhamdulilah, semua selamat, Allah telah menghantar bombaNya sendiri.
Apa yang mengejutkan teman sebenarnya ialah kenyataan Nik aziz dalam obsess nya untuk mengelakkan perpaduan Melayu dan Islam. Ambo pun tok tahu gimano dapak gelaran tok guru. Nik aziz ini patut di gelarkan Bapa perpecahan melayu. Patut yang kena buang hambo ini. Tobat banyok2.
Apa yang mengejutkan teman sebenarnya ialah kenyataan Nik aziz dalam obsess nya untuk mengelakkan perpaduan Melayu dan Islam. Ambo pun tok tahu gimano dapak gelaran tok guru. Nik aziz ini patut di gelarkan Bapa perpecahan melayu. Patut yang kena buang hambo ini. Tobat banyok2.
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