《科技英语六单元》由会员分享，可在线阅读，更多相关《科技英语六单元（8页珍藏版）》请在金锄头文库上搜索。
1、六单元Londons big question was: What kind of bridge would allow carts and horses to cross over it, and tall ships to sail under it? Horace Jones, the City Architect, had an answer: A bascule bridge. (The word bascule comes from the French word for “seesaw”.) His bridge would raise its bascules to let t
2、he tall ships pass through, and it had walkways, high above the ships masts, where pedestrians could cross as the ships passed underneath. Sadly, Horace Jones never saw Tower Bridge. He died in 1887 before the foundations were complete. The famous engineer John Wolfe Barry, who had helped Horace Jon
3、es with his bascule bridge design, oversaw the construction of Tower Bridge.曾经伦敦的一个大问题是：什么样的桥能让马车和马通过，又可以让高大的船只在桥下航行呢？城市建筑师霍勒斯琼斯(Horace Jones)给出了答案：开合桥。（活动结构这个词这个词来源于法语中的“跷跷板”。）开合桥会把它的桥面抬高，让高大的船只通过，并且它有高过船只桅杆的人行道，行人可以在船只从下面经过时通过。遗憾的是，霍勒斯琼斯没能见过塔桥。他在1887年地基还没有完工就去世了。著名的工程师约翰沃尔夫巴里曾帮助霍勒斯琼斯设计吊桥，他监督了塔桥的建造
4、。 How can you build a bridge like that, with all that boat traffic on the river? You start with the foundation. And in the case of Tower Bridge, you start deep, deep, deep under the surface of the Thames 10 meters below the surface of the water, in fact.如何能建这样一座桥，让所有的船只通过，首先要从桥基开始，就塔桥而言，事实上要从河面下深至10
5、米的地方开始。Work began on 22nd April 1886. Divers prepared the riverbed for the massive piers. It must have been a scary job after all, this was 1886. They didnt have scuba gear and safety devices and computer equipment. The divers wore leather suits with metal helmets, and they were connected to the sur
6、face by air tubes. They prepared the riverbed.1886年4月22日开始施工。潜水员为准备在河床上建巨大的桥墩。那一定是个艰巨的工作毕竟这是1886年。他们没有任何潜水装备，没有安全设备也没有计算机设备，潜水员穿着皮制的工装，头戴金属头盔，他们用通向水面的空气管道呼吸，在河床上做准备工作。Above them, on barges, other workers created caissons. Caissons are open-ended watertight boxes, with sharp edges. Workers lowered th
7、e caissons into the river down, down, down until they rested on the riverbed. While the sharp edge of the caisson dug into the riverbed, the workers forced them deep into the soil. They were sunk to 9 meters deep, into watertight London clay. The London clay would support the enormous weight of Towe
8、r Bridge.在他们上面的驳船上，其他工人制造沉箱。沉箱是两边未封闭的防水箱，边缘锋利。工人们把沉箱沉入河里，一直下沉，直到他们停留在河床上。当沉箱的尖锐边缘挖入河床时，工人们把它们深深地压进伦敦黏土里。深达9米，伦敦的黏土将支撑塔桥的巨大重量。Twenty-four caissons were constructed (12 in each pier), and when they were complete, they were filled with concrete. The workers left space within each pier for steel pillars
9、 (which would support the towers), and for the bascule machinery. It took four years to construct the piers.共建造了24个沉箱（每个桥墩12个），当沉箱完成后，即用混凝土填充。工人们在每个桥墩内留下了空间，用来建造钢柱（用来支撑塔楼）也为了活动结构机械留出空间，建造桥基耗时四年。The steel for the towers was made by William Arrol & Company in Scotland, then shipped down to London and
10、brought up the river on barges. There wasnt much space to store equipment and materials, so the steel was brought up the river when it was needed. Crews of workers set about 200 rivets per day by hand. There are two million rivets in Tower Bridge so you can do the math. The work took a long time. Sl
11、owly but surely, the steelwork rose from the Thames like a huge black skeleton. Each tower had four steel pillars. The two pillars on the land-side of the tower would support the suspension chains, while the river-side pillars would support the high level walkways.高塔的钢材由苏格兰的威廉阿罗尔公司制造，然后用驳船逆流而上运到伦敦。由
12、于没有足够的空间来储存设备和材料，所以在需要的时候钢就被拉上了河。工人们每天手工安装约200个铆钉。塔桥上有200万颗铆钉这样你就可以做计算了。这项工作花了很长时间。慢慢地，钢铁建筑从泰晤士河上拔地而起，像一具巨大的黑色骨架。每座塔有四根钢柱。塔的陆地一侧的两根柱子将支撑吊索链，而河侧的两根柱子则支撑着这些高层走道。When the pillars were finished, workers started building the high level walkways. They worked 46 meters above the river, without safety nets!
13、 Boats would pass below them, so they had to be extra careful not to drop a tool onto someones head. The workers on Tower Bridge were paid an outstanding wage of 2 per week. It may not seem like much, but it was twice the wage of a London policeman. Separate crews worked on cantilevers extending fro
14、m each tower. (A cantilever is a section supported at one end, which can bear its own weight.) When the cantilevers extended far enough toward the middle, a central section linked them together. William Arrol & Company in Scotland had tested their steel to make sure it would all fit snugly together
15、once it arrived at Tower Bridge.当柱子完成后，工人们开始建造高的人行道。他们在高于河上46米出高空作业，没有安全网！船会从下面经过，所以他们必须格外小心，以免把工具掉到别人的头上。塔桥上的工人得到每周的薪资高达2英镑的。这看起来可能不太多，但这是伦敦警察工资的两倍。不同组的工人在从每个塔延伸出来的悬臂上工作。（悬臂是一端固定的的部分，它能承受自身的重量。）当悬臂向中间延伸足够远时，中间的部分将它们连接起来。苏格兰威廉公司对他们的钢材进行了测试，以确保它们到达塔桥后，它们能够紧密地结合在一起。The suspension chains of Tower Bridg
16、e are really heavy. They weigh one ton per foot. They needed to support all that weight, so the workers built an abutment on each land-end of Tower Bridge. (An abutment is a structure which anchors suspension chains.) Then they built the suspension chains, using scaffolding to support them as they went. When the chains were finished, the workers added rods and girders to keep the chains from swinging in the wind.塔桥的吊链真的很重。他们每英尺重一吨。他们需要支撑
