The world needs bridges. Have you ever thought about what it would be like not to have any? It's hard to imagine a civilization without bridges because they're so essential for growth and development of human society, but they're not just about a safe way across a river or an obstacle. They shout about connectivity -- community. They reveal something about creativity, our ingenuity -- they even hint at our identity. And when bridges fail, or are destroyed in conflict, communities struggle, development stagnates, people suffer. Even today, there are over one billion people living in poor, rural communities around the world that do not have safe, year-round access to the things that you and I take for granted: education, medical care, access to markets ... which is why wonderful organizations like Bridges to Prosperity build bridges in this kind of place -- this is in Rwanda. And they make such a difference, not only to those lives immediately around the bridge, but the impact of these bridges is huge, and it spreads over the whole community, far, far away.
世界需要桥梁。 你们有想过一个没有桥的世界吗? 很难去想像一个没有桥的文明, 因为在人类社会的发展过程中, 桥梁始终都是不可或缺的, 桥梁不仅让我们安全地 跨过河流或者障碍, 它们更象征着一种连通性—— 将社区彼此连接。 它们体现了创造力, 我们的智慧—— 甚至还暗示着我们的身份。 而当桥垮了, 或在冲突中被毁, 社区受创, 发展受阻,人民受苦。 即便今天, 全球仍有超过十亿人 生活在贫困的乡村, 他们没法随时随地享受到 我们习以为常的安全的资源: 如教育,医保,商场等等... 这就是诸如“繁荣之路” 那样伟大的组织 在这种地方修桥的原因—— 这是卢旺达。 他们让一切变得大不同, 不仅对住在大桥周边的人, 而且这些桥的影响是巨大的, 延伸至整个社区, 直到很远很远的地方。
Of course bridges have been around for an awfully long time. The oldest ones are stone because it's a very durable material. I don't know about you -- I love to look at the development of technology to learn about what people did with the materials and tools available to them at the time. So the Pont Du Gard in the center is a wonderful example -- Roman aqueduct in the South of France -- fantastic piece of technology built using massive stones put together, dry -- there's no mortar in those joints. They're just dry stone joints -- fantastic and almost as good as new today. Or sometimes up in the mountains, people would build these suspension bridges, often across some dizzy canyon, using a vine. In this case, this is in Peru. This is using grass which grows locally and is woven into ropes to build these bridges. And do you know they rebuild this every year? Because of course grass is not a durable material. So this bridge is unchanged since Inca times.
当然,桥梁很早之前就出现了。 最早的桥是石桥, 因为石头是一种非常耐用的材料。 我不知道你们怎么想—— 我个人最喜欢目睹科技的发展, 去了解人们是怎样使用当时的 材料和工具的。 图中的加尔桥 就是一个完美的例子—— 这是位于法国南部的 古罗马引水桥—— 通过精妙绝伦的技术 将巨大的重石堆在一起—— 连接处没有任何砂浆。 它们完全用石头搭建起来—— 太了不起了, 而且现在依旧完好如初。 有时候在高山之中, 人们会建这样的吊桥, 通常用于跨越恐怖的峡谷, 只使用藤曼。 这个例子是在秘鲁。 他们使用本地生长的一种草 编织成绳子来建成这些桥。 你知道他们每年都会重建吗? 当然是因为这些草并不耐用。 这些桥从印加文明时期 就没有改变过。
And bridges can be symbols of their location. Of course, Golden Gate and Sydney are well familiar. In Mostar the bridge was synonymous with the name of the place, and to such an extent that in the war in 1993 when the bridge was destroyed, the town all but lost its identity until the bridge was reconstructed. And bridges are enormous features in our landscape -- not just enormous, sometimes there's small ones -- and they are really significant features, and I believe we have a duty to make our bridges beautiful. Thankfully, many people do. Think of the stunning Millau Viaduct in the South of France. French engineer Michel Virlogeux and British architect Lord Foster collaborated together to produce something which is a really spectacular synergy of architecture and engineering. Or Robert Maillart's Salginatobel Bridge in the mountains in Switzerland -- absolutely sublime. Or more recently, Laurent Ney's beautiful and rather delicate bridge for Tintagel Castle in the UK. These are spectacular and beautiful designs and we need to see more of this.
桥梁也是居住地的地标。 当然,金门大桥和悉尼更为人所知。 在莫斯塔尔,桥梁用当地的地名命名, 某种意义上,如在1993年的战争中, 当桥梁被摧毁, 这座城镇就失去了灵魂, 直至这座桥被重建。 桥也是我们的 景观中的一大特色—— 不仅是大桥,小桥也一样—— 而它们真的是非常有特色, 而我认为,我们有责任 让桥梁更加美观。 幸运的是,有很多人这样做了。 想想让人惊叹的 法国南部的米约高架桥。 法国工程师Michel Virlogeux和 英国建筑师Lord Foster 合作建造了这座桥, 它是建筑与工程辉煌的融合体。 或者是位于瑞士山间的 Robert Maillart的Salginatobel桥—— 十分宏伟壮观。 还有最近时期的, Laurent Ney为英国的 廷塔杰尔城堡所打造的 精妙绝伦的桥。 这些都是设计巧夺天工的桥, 我们期待更多这样的作品。
Bridges can be considered in three convenient categories, depending on the nature of the structural system that they adopt as their principal support. So, bending, of course, is the way a beam will behave -- so, beams and bending. Or compression is the principal way of operating for an arch. Or for the really long spans you need to go lightweight, as we'll see in a minute, and you'll use tension, cables -- suspension bridges. And the opportunity for variety is enormous. Engineers have a fantastic scope for innovation and ingenuity and developing different forms around these types.
桥梁一般可以分为三类, 是根据桥梁的 结构受力体系来划分的。 弯曲是梁式桥的受力体系—— 梁式桥会受到弯曲力。 承压是拱桥的主要受力体系。 还有对于跨度很宽的桥, 就需要自重轻, 我们等会儿都会看到, 你会用到张力,缆绳—— 悬索桥。 多样化的潜力是无限的。 工程师在创新和创造方面 有非凡的眼界, 他们可以围绕这些类型 建造各种各样的桥梁。
But technological change happens relatively slowly in my world, believe it or not, compared to the changes that happen in mobile phone technology and computers and digital technologies and so on. In our world of construction, the changes seem positively glacial. And the reason for this can be summarized in one word: risk. Structural engineers like me manage risk. We are responsible for structural safety. That's what we do. And when we design bridges like these, I have to balance the probability that loads will be excessive on one side or the strength will be too low on the other side. Both of which, incidentally, are full of uncertainty usually, and so it's a probabilistic problem, and we have to make sure that there's an adequate margin for safety between the two, of course. There's no such thing, I have to tell you, as absolute safety. Contrary to popular belief, zero risk doesn't exist.
不管你们信不信,与移动电话和 电脑,以及其他数字技术上的 变化相比, 技术发展的速度在 我的(建筑)世界里 是相对比较缓慢的。 在我们的建筑世界中, 这些变化似乎非常缓慢。 原因可以用一个词来概括: 风险。 像我这样的结构工程师 需要管理风险。 我们为结构的安全性负责。 这是我们的工作。 当我们在设计这样的桥梁时, 我必须平衡一边的负荷会超载, 或另一边的强度太低 等情况发生的概率。 这两种情况通常都充满了不确定性, 所以这是一个概率问题, 当然,我们必须确保 这两者之间有足够的安全空间。 我得告诉你们,世界上并没有 绝对的安全。 和大众普遍的看法相反, 零风险是不存在的。
Engineers have to do their calculations and get their sums right to make sure that those margins are there, and society expects them to do so, which is why it's all the more alarming when things like this happen. I'm not going to go into the reasons for these tragedies, but they are part of the reason why technological change happens quite slowly. Nobody wants this to happen. Clients don't want this to happen on their projects, obviously. And yet of course they want innovation. Innovation is vital. As an engineer, it's part of my DNA. It's in my blood. I couldn't be a very good engineer if I wasn't wanting to innovate, but we have to do so from a position of knowledge and strength and understanding. It's no good taking a leap in the dark, and civilization has learned from mistakes since the beginning of time -- no one more so than engineers.
工程师们需要完成这些计算 并得出正确的结果, 以确保留出了足够的安全空间, 这是社会所期望的, 这也是这些事情发生时 让人警醒的原因。 我不打算深入分析 这些悲剧发生的原因。 但它们是 技术变化之所以缓慢的部分原因。 没人想让这样的事情发生。 客户当然不希望它们的工程 发生这样的悲剧,这是显而易见的。 当然,他们也想要创新。 创新是至关重要的。 作为工程师,这是我DNA的一部分。 融入在我的血液中。 如果不想创新,我就 不是一个好的工程师, 但我们只能以知识,力量和理解 为基础才能实现创新。 盲目激进是没有用的, 文明需要从错误中学习, 从一开始就是这样—— 没人比工程师更明白这一点。
Some of you may have seen this film before -- this is the very famous Tacoma Narrows Bridge collapse in Tacoma, Washington state, 1940. The bridge became known as "Galloping Gertie" because she -- she? Is a bridge female? I don't know. She was wobbling like this for quite a long time, and notice this twisting motion. The bridge was far too flexible. It was designed by a chap called Leon Moisseiff, no stranger to suspension bridge design, but in this case he pushed the limits just that little bit too far and paid the price. Thankfully, nobody was killed. But this bridge collapse stopped suspension bridge development dead in its tracks. For 10 years nobody thought about doing another suspension bridge. There were none. And when they did emerge in the 1950s, they were an understandable overreaction, this sort of oversafe response to what had happened. But when it did occur in the mid-60s, there was indeed a step change -- an innovation, a technological step change. This is the Severn Bridge in the UK. Notice the aerodynamically streamlined cross section in the center there. It's also a box which makes it very torsionally stiff -- that twisting motion which we saw at Tacoma would not happen here. And it's also really lightweight, and as we'll see in a moment, lightweight is really important for long spans, and everybody seems to want us to build longer spans.
有些人可能看过这个影片—— 这是华盛顿州知名的塔科马桥 倒塌的画面, 发生在1940年。 这桥后来被称为“舞动的格蒂”, 因为她——她? 桥的性别是女的吗?我也不知道。 她像这样摇摆了很长一段时间, 注意这个扭曲的运动。 这座桥实在是太有弹性了。 它是由一个叫 Leon Moisseiff的人设计的, 他并非悬索桥的设计新手, 但在这个案例中, 他把极限推得太过了, 并为此付出了代价。 幸运的是,没人因此丧命。 但是这座桥的倒塌阻止了 悬索桥的发展。 在随后10年间,没有人 想去建造另一座悬索桥了。 没有人。 当他们在1950年代 想去建造这样的桥时, 人们有点过度反应了, 这是对所发生事情的 过度安全反应。 但当这样的桥在 60年代中期又出现时, 情况已经大大改观—— 创新,技术上的进步出现了。 这是英国的塞汶大桥。 注意看中间的空气动力流线型的 横截面。 这个盒子结构使其非常稳固—— 在塔科马看到的这种 扭曲运动就不会在这儿发生。 而它的自重也很轻, 我们马上会看到, 自重轻对于长跨度非常关键, 每个人似乎都想让我们去 建造更长跨度的桥。
The longest at the moment is in Japan. It's just under 2,000 meters -- one span. Just under two kilometers. The Akashi Kaikyō Bridge. We're currently working on one in Turkey which is a bit longer, and we've designed the Messina Bridge in Italy, which is just waiting to get started with construction one day, who knows when.
目前跨度最长的桥在日本。 它只有不到两公里—— 一个跨度。 不到两公里。 日本明石海峡桥。 我们在土耳其正建造的桥要长一些, 而我们设计的意大利梅西纳大桥 则正等着开工建设, 天知道什么时候才能动工。
(Laughter)
(笑声)
I'm going to come back to Messina in a moment. But the other kind of long-span bridge which uses that tension principle is the cable-stayed bridge, and we see a lot of these. In fact, in China they're building a whole load of these right now. The longest of these is the Russky Bridge in Vladivostok, Russia -- just over 1,100 meters.
我等会儿再回到梅西纳桥。 而另一种使用这种 张力原理的长跨桥 是斜拉桥, 我们看过很多这样的桥。 事实上,在中国,他们正在 建造大量的这类建筑。 其中最长的是俄罗斯 海参葳的Russky桥。 刚刚超过1100米。
But let me take you back to this question about long-span and lightweight. This is using Messina Bridge as an example. The pie chart in the center represents the capacity of the main cables -- that's what holds the bridge up -- the capacity of the main cables. And notice that 78 percent of that capacity is used up just holding the bridge up. There's only 22 percent of its capacity -- that's less than a quarter -- available for the payload, the stuff that the bridge is there to support: the railway, the road and so on. And in fact, over 50 percent of that payload -- of that dead load -- is the cable on its own. Just the cable without any bridge deck. If we could make that cable lighter, we could span longer. Right now if we use the high-strength steel wire available to us, we can span, practically speaking, around about five or six kilometers if we really push it. But if we could use carbon fiber in those cables, we could go more than 10 kilometers. That's pretty spectacular.
我们再回到长跨度 和自重轻的问题。 用梅西纳大桥来举例。 中间的饼状图展现的是 主缆的承载力—— 就是是支撑桥的力量, 主揽的承载力。 注意,有78%的承载力 被用来支撑桥体的重量。 只有22%的承载力, 不到其1/4—— 用于有效载荷, 用于桥所支撑的东西: 如铁路,道路,等等。 而事实上, 超过50%的有效载荷, 静载荷—— 是缆绳本身。 只是缆绳,不含桥面。 如果我们可以让缆绳变轻, 就可以实现更长的跨度。 如果我们使用高强度钢丝, 实际上可以实现 大约5到6公里的跨度, 努努力的话。 但如果我们在这些 缆绳中使用碳纤维, 就可以建跨度超过10公里的桥。 这是个让人惊叹的数字。
But of course superspans is not necessarily the way to go everywhere. They're very expensive and they've got all sorts of other challenges associated with them, and we tend to build multispan when we're crossing a wide estuary or a sea crossing. But of course if that sea crossing were somewhere like Gibraltar, or in this case, the Red Sea, we would indeed be building multiple superlong spans and that would be something spectacular, wouldn't it? I don't think I'm going to see that one finished in my lifetime, but it will certainly be worth waiting for for some of you guys.
不过当然,超级跨度 并不一定适合于任何地方。 它们造价昂贵, 而且还有伴随而来的各种挑战, 当我们在跨越宽阔的河口或海湾时, 我们倾向于建造多跨度桥。 当然,如果那个海上通道 是像直布罗陀这样的地方, 或者这个例子中的,红海, 我们确实会建造多个超长的跨度, 那的确相当壮观,不是吗? 我想我不会在有生之年 看到这个完成了, 但对在座的有些人来说, 倒是值得期待一下。
Well, I want to tell you about something which I think is really exciting. This is a multispan suspension bridge across very deep water in Norway, and we're working on this at the moment. The deep water means that foundations are prohibitively expensive. So this bridge floats. This is a floating, multispan suspension bridge. We've had floating bridges before, but nothing like this. It stands on floating pontoons which are tethered to the seabed and held down -- so, pulled down against those buoyancy forces, and in order to make it stable, the tops of the towers have to be tied together, otherwise the whole thing would just wobble around and nobody will want to go on that. But I'm really excited about this because if you think about the places around the world where the water is so deep that nobody has given a second thought to the possibility of a bridge or any kind of crossing, this now opens up that possibility. So this one's being done by the Norwegian Roads Administration, but I'm really excited to know where else will this technology enable development -- that growing together, that building of community.
我想告诉大家一个 我觉得非常让人激动的事情。 这是挪威一座跨越 非常深的水域的悬索桥, 我们目前仍在施工中。 深水意味着打造地基的成本 高得让人望而却步。 所以这座桥是漂浮着的。 这是座漂浮的多跨度悬索桥。 我们以前建过浮桥, 但没造过这样的东西。 它站在浮动的浮筒上, 这些浮筒被拴在 海床上并被压住—— 以对抗浮力。 为了保持稳定。 塔楼的顶部必须绑在一起, 否则整个结构就会发生摆动, 没人想从上面过去。 我对这种设计非常感兴趣, 因为你想想,全球各地 那些水深的地方, 没人曾考虑过打造桥 或其他任何通行工具的 可能性, 而这座桥开启了这种可能。 这是由挪威公路管理局完成的, 而我迫不及待地想知道 这个技术还能 推动哪些地方的发展—— 增强联系, 构建社区。
Now, what about concrete? Concrete gets a pretty bad name sometimes, but in the hands of people like Rudy Ricciotti here, look what you can do with it. This is what we call ultra-high performance fiber-reinforced concrete. It's a bit of a mouthful. Us engineers love those kinds of words.
那么,混凝土呢? 有时候混凝土并不很实用, 但是在像鲁迪里奇奥蒂 这样的人手中, 看看你可以用它来做什么吧。 这就是我们所说的 超高性能纤维增强混凝土。 有点拗口。 美国工程师喜欢这些词。
(Laughter)
(笑声)
But what you do with this -- this is really superstrong, and it's really durable, and you can get this fantastic sculptural quality. Who said concrete bridges are dull?
但你能用它来建造什么呢—— 这种材料非常结实耐用, 你可以得到这种神奇的 雕塑般的效果。 谁说混凝土桥梁呆板无趣?
We could talk about all sorts of other new technologies and things which are going on, robots and 3-D printing and AI and all of that, but I want to take you back to something which I alluded to earlier on. Our bridges need to be functional, yes. They need to be safe -- absolutely. They need to be serviceable and durable. But I passionately believe they need to be elegant; they need to be beautiful. Our bridges are designed for a long time. We tend to design for 100 years plus. They're going to be there for an awfully long time. Nobody is going to remember the cost. Nobody will remember whether it overran a few months. But if it's ugly or just dull, it will always be ugly or dull.
我们可以谈论 各种各样的正在发展的 新技术和新事物, 机器人,3D打印,人工智能等等, 但是我想带你们回到 我之前提到的一些东西。 我们的桥梁必须是 功能性的,是的。 它们必须是安全的——绝对的。 它们需要实用和耐用。 但我坚信,它们也需要造型优雅, 时尚美观。 我们的桥梁设计 考虑到了经久耐用。 服务寿命在100年以上。 它们将在那里呆很长时间。 没人记得建造成本。 没有人会记得是否 它们已经寿终正寝。 但是如果它是丑陋的,或是无趣的, 就一直是丑陋或无趣的。
(Laughter)
(笑声)
Bridges -- beauty enriches life. Doesn't it? It enhances our well-being. Ugliness and mediocrity does exactly the opposite. And if we go on building mediocre, ugly environments -- and I believe we're becoming numb to that stuff -- if we go on doing that, it's something like a large-scale vandalism, which is completely unacceptable.
桥梁—— 美丽能够丰富生活。 不是吗? 它能提升我们的幸福感。 丑陋和平庸则恰恰相反。 如果我们继续建设 平庸丑陋的环境—— 我相信我们对 这些东西已经麻木了—— 如果我们继续这样做, 就如大规模的破坏行为, 这是完全不可接受的。
(Applause)
(鼓掌)
This is a bridge in Lyon in France, which was procured through a design competition. And I think we need to start talking to those people who procure our bridges and our structures, because it's the procurement which is often the key. Design competitions is one way to get good design, but it's not the only one. There's an awful lot of procurement going on that is absolutely prejudiced against good design.
这是法国里昂的一座桥, 他的设计灵感来源于一场设计比赛。 我认为我们需要开始 和那些采购我们的桥梁, 我们的结构的人谈谈, 因为采购过程常常很关键。 设计比赛是得到好设计的一种方法, 但不是唯一的方法。 大量正在进行的采购中, 不乏一些对好设计的偏见。
So yes, technology happens a bit slowly sometimes in my world. But I'm really excited about what we can do with it. Whether it's saving lives in rural Africa or stretching the boundaries of long-span technology or just crossing the road next-door, I hope we continue to build elegant and beautiful stuff that save lives and build communities.
是的,技术在我们这个世界 有时候发展比较缓慢。 但我依然对现在 所能做的事感到无比兴奋。 不管是在非洲农村拯救生命, 还是扩展长跨技术的边界, 甚至只是穿过隔壁的马路, 我希望我们能持续建造 优雅和美丽的事物, 来拯救生命和构建社区。
Thank you.
谢谢。
(Applause)
(鼓掌)