阿摩線上測驗
47 Which of the following materials have NOT been used as cables for suspension bridges?
(A) Iron.
(B) Wood.
(C) Steel.
(D) Vines.
答案：登入後查看
統計： A(43), B(438), C(41), D(71), E(0) #1483715
統計： A(43), B(438), C(41), D(71), E(0) #1483715
詳解 (共 3 筆)
骨頭（四等一般警特正取）
#3622911
A suspension bridge吊橋 is a type of bridge that use overhead空中 cables to support its roadway車道.
The design of a suspension bridge is simple and straightforward容易理解的, and uses several architectural建築學 techniques to distribute分發 the weight of the bridge safely and evenly平均地.
The construction of a suspension bridge starts with its towers塔, which are usually located on dry land and anchored支持 to bedrock. Once the towers are built, master主 cables電纜 are strung捆 across them and anchored into the bank岸 at both ends of the bridge.
Next, suspension cables電纜 are strung捆 from the master cables電纜, and then the deck甲板 used as roadway is attached連接 to them.
Most of the weight of the bridge is transferred by the cables to the anchorage systems锚定系统.
These are embedded嵌入 in either solid rock堅石 or huge concrete混凝土 blocks塊.
Inside the anchorages, the cables電纜 are spread over a large area to evenly distribute分發 the load負重 and to prevent the cables from breaking free.
One of the oldest engineering工程 forms, suspension bridges were constructed by primitive早期 peoples using thick vines for cables電纜.
A much stronger type was introduced in India around 400 A.D. that used cables of braided bamboo竹編扇.
In the early nineteenth century, suspension bridges used iron chains for cables.
Today, the cables are made of thousands of individual steel鋼 wires bound束縛 tightly together.
A single steel wire, only 0.1 inch thick, can support over half a ton公噸 of weight without breaking.
Light and strong, a suspension bridge could span跨 distances from 2,000 to 7,000 feet, which is much longer than any other kind of bridge could.
Its simple design allows high clearance空隙 under the deck甲板, useful when the bridge is built over a major shipping船運 waterway or a very deep gulf海灣.
A suspension bridge is also less subjected to collapse倒塌 than some other bridge types such as those built on support pillars柱子.
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