Bridge against a setting sun in the Pacific Ocean, • 在夕阳中太平洋上金门大桥的深红色网格的景象
2
• or the arch of the Gambit Viaduct soaring triumphantly above the deep gorge,
• 这些桥梁的设计和建设安排都被认为是有如梦一样 的想象力的.但是想象力和决心是不够的。
4
• All the physical forces of nature and gravity must be understood with mathematical precision
• 所有自然界的力和重力都必须在数学上精密的被理 解
• 像Stephenson和Roebling这样的伟大桥梁大师针对于很复杂的 结构问题提出了实际的解决办法，而正确的理论解决办法在很 多年之后才被推导出来
8
• in fact the clue to the latter was provided by the former. • 实际上，后者（correct mathematical solution）的线
• 计算技术现在广泛应用于复杂的理论的计算
6Leabharlann • but it is still not possible to accurately cater for all the known and unknown intricacies.
• 但是精确解决所有已知和未知难题还是不可能的 • even the most advanced theories and techniques have
7
• hence scientific knowledge has to be tempered with a judgement as to how far to rely on mathematical answers and then what provision to make for the unknown realities.
• 这些桥梁是人类想通过移除一切障碍来追求一个更 好更自由的世界的坚定的表达。
• their design and building schemes are conceived in dream-like vision. But vision and determination are not enough.
• and such forces have to be resisted by manipulating the right materials in the right pattern.
• 并且这些力必须 通过在正确的结构中熟练使用正确 材料 来阻止。
5
• this requires both the inspiration of an artist and the skill of an artison.
• 或者是加拉比高架桥的拱在深谷中胜利的高飞 • （sight）fills one's heart with wonder and admiration
for the art of their builders. • 这些景象让人们感到惊奇，并且充满对建筑者的艺
术创造力的崇拜
3
• They are the enduring expressions of mankind's determination to remove all barriers in its pursuit of a better and freer world.
• 这同时需要艺术家的灵感和工匠的操作技术。
• Scientific knowledge about materials and structural behavior has expanded tremendously,
• 关于材料和结构性能的科学知识已经迅猛地发展
• and computing techniques are now widely available to manipulate complex theories in innumerable ways very quickly.
• 因此科学知识必须和相关的评价调和，以至于得知离可以依靠 理论答案有多远。然后，需要对未知的现实做什么准备
• great bridge-builders like Stephenson and Roebling provided practical solution to some very complex structural problems,for which correct mathematical solutions were derived many years later.
their approximations and exception. • 即使是最先进的理论和技术都存在着粗略估计和例
外
• the wiser the scientist, the more he knows of his limitations.
• 一个科学家，他越机智，就越明白自己知道的太少。
Lesson 17 Bridges
—group 3
1
• Bridges are great symbols of mankind’s conquest of space.
• 桥梁是人类征服空间的伟大象征。 • The sight of the crimson tracery of the Golden Gate
索是前者（practical soution）提供的 • for permanent bridges, the most commonly used
material are steels and concrete. • 对于永久使用的大桥来说，钢材和混凝土是最常使
用的材料
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• bridges of many different types are built with these materials, used singly or in combination.