The world needs bridges. Have you ever thought about what it would be like not to have any?
世界需要桥梁。你们有想过一个没有桥的世界吗？
It's hard to imagine a civilization without bridges because they're so essential for growth and development of human society,
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，
but they're not just about a safe way across a river or an obstacle.
桥梁不仅让我们安全地跨过河流或者障碍，
They shout about connectivity -- community.
它们更象征着一种连通性--将社区彼此连接。
They reveal something about creativity, our ingenuity -- they even hint at our identity.
它们体现了创造力，我们的智慧--甚至还暗示着我们的身份。
And when bridges fail, or are destroyed in conflict, communities struggle, development stagnates, people suffer.
而当桥垮了，或在冲突中被毁，社区受创，发展受阻，人民受苦。
Even today, there are over one billion people living in poor, rural communities around the world
即便今天，全球仍有超过十亿人生活在贫困的乡村，
that do not have safe, year-round access to the things that you and I take for granted: education, medical care, access to markets...
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...
which is why wonderful organizations like Bridges to Prosperity build bridges in this kind of place -- this is in Rwanda.
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。
And they make such a difference, not only to those lives immediately around the bridge,
他们让一切变得大不同，不仅对住在大桥周边的人，
but the impact of these bridges is huge, and it spreads over the whole community, far, far away.
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.
当然，桥梁很早之前就出现了。
The oldest ones are stone because it's a very durable material.
最早的桥是石桥，因为石头是一种非常耐用的材料。
I don't know about you -- I love to look at the development of technology
我不知道你们怎么想--我个人最喜欢目睹科技的发展，
to learn about what people did with the materials and tools available to them at the time.
去了解人们是怎样使用当时的材料和工具的。
So the Pont Du Gard in the center is a wonderful example -- Roman aqueduct in the South of France
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，
fantastic piece of technology built using massive stones put together, dry -- there's no mortar in those joints.
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。
They're just dry stone joints -- fantastic and almost as good as new today.
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。
Or sometimes up in the mountains, people would build these suspension bridges, often across some dizzy canyon, using a vine.
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。
In this case, this is in Peru. This is using grass which grows locally and is woven into ropes to build these bridges.
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。
And do you know they rebuild this every year?
你知道他们每年都会重建吗？
Because of course grass is not a durable material. So this bridge is unchanged since Inca times.
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.
桥梁也是居住地的地标。当然，金门大桥和悉尼更为人所知。
In Mostar the bridge was synonymous with the name of the place,
在莫斯塔尔，桥梁用当地的地名命名，
and to such an extent that in the war in 1993 when the bridge was destroyed,
某种意义上，如在1993年的战争中，当桥梁被摧毁，
the town all but lost its identity until the bridge was reconstructed.
这座城镇就失去了灵魂，直至这座桥被重建。
And bridges are enormous features in our landscape -- not just enormous, sometimes there's small ones
桥也是我们的景观中的一大特色--不仅是大桥，小桥也一样，
and they are really significant features, and I believe we have a duty to make our bridges beautiful.
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。
Thankfully, many people do. Think of the stunning Millau Viaduct in the South of France.
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。
French engineer Michel Virlogeux and British architect Lord Foster collaborated together to produce something
法国工程师Michel Virlogeux和英国建筑师Lord Foster合作建造了这座桥，
which is a really spectacular synergy of architecture and engineering.
它是建筑与工程辉煌的融合体。
Or Robert Maillart's Salginatobel Bridge in the mountains in Switzerland -- absolutely sublime.
或者是位于瑞士山间的Robert Maillart的Salginatobel桥--十分宏伟壮观。
Or more recently, Laurent Ney's beautiful and rather delicate bridge for Tintagel Castle in the UK.
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。
These are spectacular and beautiful designs and we need to see more of this.
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,
桥梁一般可以分为三类，
depending on the nature of the structural system that they adopt as their principal support.
是根据桥梁的结构受力体系来划分的。
So, bending, of course, is the way a beam will behave -- so, beams and bending.
弯曲是梁式桥的受力体系--梁式桥会受到弯曲力。
Or compression is the principal way of operating for an arch.
承压是拱桥的主要受力体系。
Or for the really long spans you need to go lightweight, as we'll see in a minute,
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，
and you'll use tension, cables -- suspension bridges.
你会用到张力，缆绳--悬索桥。
And the opportunity for variety is enormous.
多样化的潜力是无限的。
Engineers have a fantastic scope for innovation and ingenuity and developing different forms around these types.
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,
不管你们信不信，技术发展的速度在我的（建筑）世界里是相对比较缓慢的。
compared to the changes that happen in mobile phone technology and computers and digital technologies and so on.
这是与移动电话和电脑以及其他数字技术上的变化相比。
In our world of construction, the changes seem positively glacial.
在我们的建筑世界中，这些变化似乎非常缓慢。
And the reason for this can be summarized in one word: risk.
原因可以用一个词来概括：风险。
Structural engineers like me manage risk. We are responsible for structural safety. That's what we do.
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。
And when we design bridges like these,
当我们在设计这样的桥梁时，
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.
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。
Both of which, incidentally, are full of uncertainty usually, and so it's a probabilistic problem,
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，
and we have to make sure that there's an adequate margin for safety between the two, of course.
当然，我们必须确保这两者之间有足够的安全空间。
There's no such thing, I have to tell you, as absolute safety. Contrary to popular belief, zero risk doesn't exist.
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,
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，
and society expects them to do so, which is why it's all the more alarming when things like this happen.
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。
I'm not going to go into the reasons for these tragedies,
我不打算深入分析这些悲剧发生的原因，
but they are part of the reason why technological change happens quite slowly.
但它们是技术变化之所以缓慢的部分原因。
Nobody wants this to happen. Clients don't want this to happen on their projects, obviously.
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。
And yet of course they want innovation. Innovation is vital. As an engineer, it's part of my DNA.
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。
It's in my blood. I couldn't be a very good engineer if I wasn't wanting to innovate,
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，
but we have to do so from a position of knowledge and strength and understanding.
但我们只能以知识、力量和理解为基础才能实现创新。
It's no good taking a leap in the dark,
盲目激进是没有用的，
and civilization has learned from mistakes since the beginning of time -- no one more so than engineers.
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.
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。
The bridge became known as "Galloping Gertie" because she -- she? Is a bridge female? I don't know.
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。
She was wobbling like this for quite a long time, and notice this twisting motion.
她像这样摇摆了很长一段时间，注意这个扭曲的运动。
The bridge was far too flexible. It was designed by a chap called Leon Moisseiff, no stranger to suspension bridge design,
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，
but in this case he pushed the limits just that little bit too far and paid the price.
但在这个案例中，他把极限推得太过了，并为此付出了代价。

Thankfully, nobody was killed. But this bridge collapse stopped suspension bridge development dead in its tracks.
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。
For 10 years nobody thought about doing another suspension bridge. There were none.
在随后10年间，没有人想去建造另一座悬索桥了。没有人。
And when they did emerge in the 1950s, they were an understandable overreaction,
当他们在20世纪50年代想去建造这样的桥时，人们有点过度反应了，
this sort of oversafe response to what had happened.
这是对所发生事情的过度安全反应。
But when it did occur in the mid-60s, there was indeed a step change -- an innovation, a technological step change.
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。
This is the Severn Bridge in the UK. Notice the aerodynamically streamlined cross section in the center there.
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。
It's also a box which makes it very torsionally stiff -- that twisting motion which we saw at Tacoma would not happen here.
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。
And it's also really lightweight, and as we'll see in a moment,
而它的自重也很轻，我们马上会看到，
lightweight is really important for long spans, and everybody seems to want us to build longer spans.
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.
目前跨度最长的桥在日本。它只有不到两公里--一个跨度。
Just under two kilometers. The Akashi Kaikyō Bridge.
不到两公里。日本明石海峡桥。
We're currently working on one in Turkey which is a bit longer,
我们在土耳其正建造的桥要长一些，
and we've designed the Messina Bridge in Italy, which is just waiting to get started with construction one day, who knows when.
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。
I'm going to come back to Messina in a moment.
我等会儿再回到梅西纳桥。
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.
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。
In fact, in China they're building a whole load of these right now.
事实上，在中国，他们正在建造大量的这类建筑。
The longest of these is the Russky Bridge in Vladivostok, Russia -- just over 1,100 meters.
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.
我们再回到长跨度和自重轻的问题。
This is using Messina Bridge as an example.
用梅西纳大桥来举例。
The pie chart in the center represents the capacity of the main cables
中间的饼状图展现的是主缆的承载力，
that's what holds the bridge up -- the capacity of the main cables.
就是是支撑桥的力量，主揽的承载力。
And notice that 78 percent of that capacity is used up just holding the bridge up.
注意，有78%的承载力被用来支撑桥体的重量。
There's only 22 percent of its capacity -- that's less than a quarter -- available for the payload,
只有22%的承载力，不到其1/4--用于有效载荷，
the stuff that the bridge is there to support: the railway, the road and so on.
用于桥所支撑的东西：如铁路，道路，等等。
And in fact, over 50 percent of that payload -- of that dead load -- is the cable on its own.
而事实上，超过50%的有效载荷，静载荷--是缆绳本身。
Just the cable without any bridge deck. If we could make that cable lighter, we could span longer.
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。
Right now if we use the high-strength steel wire available to us,
如果我们使用高强度钢丝，
we can span, practically speaking, around about five or six kilometers if we really push it.
实际上可以实现大约5到6公里的跨度，努努力的话。
But if we could use carbon fiber in those cables, we could go more than 10 kilometers. That's pretty spectacular.
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.
不过当然，超级跨度并不一定适合于任何地方。
They're very expensive and they've got all sorts of other challenges associated with them,
它们造价昂贵，而且还有伴随而来的各种挑战，
and we tend to build multispan when we're crossing a wide estuary or a sea crossing.
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。
But of course if that sea crossing were somewhere like Gibraltar, or in this case, the Red Sea,
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，
we would indeed be building multiple superlong spans and that would be something spectacular, wouldn't it?
我们确实会建造多个超长的跨度，那的确相当壮观，不是吗？
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.
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.
我想告诉大家一个我觉得非常让人激动的事情。
This is a multispan suspension bridge across very deep water in Norway, and we're working on this at the moment.
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。
The deep water means that foundations are prohibitively expensive. So this bridge floats.
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。
This is a floating, multispan suspension bridge. We've had floating bridges before, but nothing like this.
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。
It stands on floating pontoons which are tethered to the seabed and held down
它站在浮动的浮筒上，这些浮筒被拴在海床上并被压住
so, pulled down against those buoyancy forces, and in order to make it stable,
以对抗浮力，为了保持稳定，
the tops of the towers have to be tied together,
塔楼的顶部必须绑在一起，
otherwise the whole thing would just wobble around and nobody will want to go on that.
否则整个结构就会发生摆动，没人想从上面过去。
But I'm really excited about this because if you think about the places around the world where the water is so deep
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，
that nobody has given a second thought to the possibility of a bridge or any kind of crossing, this now opens up that possibility.
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。
So this one's being done by the Norwegian Roads Administration,
这是由挪威公路管理局完成的，
but I'm really excited to know where else will this technology enable development -- that growing together, that building of community.
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,
那么，混凝土呢？有时候混凝土并不很实用，
but in the hands of people like Rudy Ricciotti here, look what you can do with it.
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。
This is what we call ultra-high performance fiber-reinforced concrete.
这就是我们所说的超高性能纤维增强混凝土。
It's a bit of a mouthful. Us engineers love those kinds of words.
有点拗口。美国工程师喜欢这些词。
But what you do with this -- this is really superstrong, and it's really durable,
但你能用它来建造什么呢--这种材料非常结实耐用，
and you can get this fantastic sculptural quality. Who said concrete bridges are dull?
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,
我们可以谈论各种各样的正在发展的新技术和新事物，
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.
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。
Our bridges need to be functional, yes. They need to be safe -- absolutely. They need to be serviceable and durable.
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。
But I passionately believe they need to be elegant; they need to be beautiful.
但我坚信，它们也需要造型优雅，时尚美观。
Our bridges are designed for a long time. We tend to design for 100 years plus.
我们的桥梁设计考虑到了经久耐用。服务寿命在100年以上。
They're going to be there for an awfully long time. Nobody is going to remember the cost.
它们将在那里呆很长时间。没人记得建造成本。
Nobody will remember whether it overran a few months.
没有人会记得是否它们已经寿终正寝。
But if it's ugly or just dull, it will always be ugly or dull.
但是如果它是丑陋的或是无趣的，就一直是丑陋或无趣的。
Bridges -- beauty enriches life. Doesn't it? It enhances our well-being.
桥梁--美丽能够丰富生活。不是吗？它能提升我们的幸福感。
Ugliness and mediocrity does exactly the opposite.
丑陋和平庸则恰恰相反。
And if we go on building mediocre, ugly environments -- and I believe we're becoming numb to that stuff
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，
if we go on doing that, it's something like a large-scale vandalism, which is completely unacceptable.
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。
This is a bridge in Lyon in France, which was procured through a design competition.
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。
And I think we need to start talking to those people who procure our bridges and our structures,
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，
because it's the procurement which is often the key.
因为采购过程常常很关键。
Design competitions is one way to get good design, but it's not the only one.
设计比赛是得到好设计的一种方法，但不是唯一的方法。
There's an awful lot of procurement going on that is absolutely prejudiced against good design.
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.
是的，技术在我们这个世界有时候发展比较缓慢。
But I'm really excited about what we can do with it.
但我依然对现在所能做的事感到无比兴奋。
Whether it's saving lives in rural Africa or stretching the boundaries of long-span technology or just crossing the road next-door,
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，
I hope we continue to build elegant and beautiful stuff that save lives and build communities. Thank you.
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。谢谢。