Lean Odds for Pisa’s Tower（在线收听）

Lean Odds for Pisa’s Tower

The Leaning Tower of Pisa is the most intensely observed building in the world.

Prof. John Burland (Imperial College of Science and Technology): When you come in through the west gate, and see this 1)glistening white structure 2)looming over the 3)Cathedral, with its lovely 4)symmetry, it is, it is beautiful. But it’s breathtaking, the fact that it hasn’t fallen over, that
 it’s just 5)shimmering on the edge.

Amongest the impressive buildings of Medieval Italy, the Leaning Tower of Pisa stands out as 6)strikingly original. But what makes this building so special may now destroy it. The tower isfalling over. Already the top bends four and a half meters south of the base. Some engineerscalculate that this collapse should have happened years ago. In fact, why it’s still standing is one of the mysteries surrounding the Leaning Tower of Pisa.

The Structure of the tower

The tower is a hollow 7)cylinder, twelve meters wide. In most places, the walls are almost threemeters thick. But 8)corkscrewing through the walls is a staircase wide enough for two Pisans toclimb side by side. An 9)extravagant design, which means that in some places the walls are underone meter thick. This would be just 10)adequate if the walls were solid marble. The 11)infill of stones and lime is not consistent. There are several large holes in this 12)conglomerate, created
by the medieval builder’s wooden 13)scaffold. The marble is more than a facade. It provides most of the support for the fourteen thousand ton tower and bears the stress created by the lean. That’s why many of these bricks are breaking up. Although some of these cracks are 14)superficial, one may be the start of total collapse. Because of the tower’s immense importance to Pisa, it has always been well maintained. For centuries, whenever a marble block has become damaged, a new one has been 15)chiseled out and fitted into the tower. So far, this has prevented collapse. But traditional 16)maintenance will no longer contain the extreme stress on the second storey.

The building of the tower

Medieval Italy was tower-mad. Skylines, like this one at San Gimignano, just south of Pisa, were commonplace. For the princes and merchants, the bigger your tower, the more wealth and power you 17)projected. Today Pisa is a quiet university town. But Medieval Pisa was an aggressive trading power and one of the richest cities in the world. Work began in 1172, and after about six years, the 18)masons had reached the fourth level. Then they stopped. The tower was abandoned for almost a century. This was probably due to political and economic 19)strife. But perhaps the delay was a brilliant building strategy. Thanks to the delays and corrections over generations of masons, the tower is shaped like a question mark. By the early nineties, years of scientific research have produced a painful conclusion. The more the leaning tower is studied, the more questions it poses. But, 20)infused by the determination of the Medieval masons, the engineers do not give up. They’re 21)on the verge of  22)startling discoveries.

注释：
1) glistening [5^li:sniN] a. 闪耀的，反光的
2) loom [lu:m] v. 隐约地出现；赫然耸现
3) cathedral [kE5Wi:drEl] n. 大教堂
4) symmetry [5simitri] n. 对称，匀称
5) shimmer [5FimE] v. 微微发光或闪光，发光
6) strikingly [5straikiNli] ad. 醒目地，引人侧目地
7) cylinder [5silindE] n. 圆筒，汽缸
8) corkscrew [5kC:kskru:] v. 作螺旋状前进
9) extravagant [iks5trAvE^Ent] a. 奢侈的，过度的
10) adequate [5Adikwit] a. 适当的，足够的
11) infill [5infil] n. 填实（空隙等）
12) conglomerate [kCn5^lCmErit] n. 聚集物，混合体
13) scaffold [5skAfEld] n. 绞刑台，脚手架
14) superficial [sju:pE5fiFEl] a. 表面的，肤浅的
15) chisel [5tFizl]  v. 砍凿
16) maintenance [5meintinEns] n. 维护
17) project [prE5dVekt] v. 使突出、显现出
18) mason [5meisn] n. 泥瓦匠
19) strife [straif] n. 斗争，冲突
20) infuse [in5fju:z] v. 使充满；鼓舞
21) on the verge of 接近于，濒临于
22) startling [5stB:tliN] a. 令人吃惊的

比萨斜塔不倒之谜

比萨斜塔是世界上最受关注的建筑。

约翰·伯兰教授（伦敦大学帝国理工学院）：当你从（比萨城的）西门进来，看到这座耀眼的白色建筑在教堂的后方高高地耸立着，塔身对称迷人、美丽非凡。它一直没有倒塌，而只是在倒塌的边缘闪耀着美丽的光芒，这种景象真是触目惊心。
意大利中世纪的那些令人印象深刻的建筑当中，比萨斜塔以其鲜明的独创性独树一帜。但是，如今，这座建筑的特别之处可能也将毁了它。塔在不断倾斜。塔顶已经向南偏离座基达4.5米。据一些工程师测算，塔楼本该数年前就倒塌了。事实上，比萨斜塔何以一直屹立不倒，这是斜塔的其中一个不解之谜。

斜塔的结构
斜塔是一个中空的圆柱体，宽12米。多数地方的墙壁接近3米厚。在内墙壁和外墙壁之间的螺旋型楼梯宽度足以让两个比萨人并排攀登。这是一个超乎寻常的设计，它意味着在某些地方，墙体的厚度不足1米。如果墙体是用坚固的大理石所造，那样的厚度倒也勉强足够。石块与石灰这样的填充料并不坚实，由于中世纪工匠所用的是木制的脚手架，墙体里留下了好几个大洞。大理石远非用来装饰门面，它为重达14000吨的塔楼提供了最主要的支撑作用，承担了由倾斜所导致的压力。这就是许多砖石现在会破碎的原因。尽管其中一些碎裂无关紧要，但仅仅一处就可能成为全盘崩塌的开始。由于塔楼对比萨城具有不可估量的重要性，它一直得到很好的维护。数百年来，只要有一处大理石块损坏，新的大理石就会被凿刻出来填进塔身。迄今为止，这项措施止住了塔楼的倒塌。但是，传统的维护手段再也不能缓解塔楼的第二层上所承受的强大压力。

斜塔的修建
中世纪的意大利人痴迷于塔楼。类似这座位于比萨城之南的圣·吉米尼亚诺的高塔建筑比比皆是。对王公商贾们来说，塔楼越大，显示出的财富和权力就越显赫。今天的比萨是一个宁静的大学城，但中世纪时的比萨则是一个活跃的商贸重地，也是世界上最富裕的城市之一。斜塔的建造工程开始于1172年。大约六年后，工匠们修到了第四层，然后他们停了下来。塔楼被闲置了将近一个世纪，这次延缓可能是由于政治和经济纷争所致，但这兴许也是最卓越的一个建筑策略。多亏了中间的耽搁，以及几代工匠们的矫正，塔楼被修筑得像一个问号。二十世纪九十年代的早期，经过数年科学研究，人们得出一个痛苦的结论。对斜塔的研究越深入，它显示出来的问题也越多。但是，受到中世纪工匠们坚定决心的鼓舞，工程师们并没有放弃。他们即将得出一些令人震惊的发现。