
Chinese: 
灾难科学：世贸大厦
欢迎来到灾难科学
我们将为您介绍因为灾难而进行的
可以拯救生命的科学研究
恐怖袭击让世贸大厦令人意外的顷刻倒塌
超过2700人因此丧命
由此  如何更好地建造建筑  并防止人员伤亡
成为了工程师们的重要议题
UNSW的工程师们在热度对钢的影响、
高性能混凝土和城市环境中的爆炸进行了研究
就世贸大厦来说
它的倒塌归咎于其建筑的设计
世贸大厦的横梁的刚性很大
同时又非常长
跨度从楼内的电梯井直到边柱
这种无中柱设计本来是
为了不影响楼面的租赁价值
飞机的撞击可能破坏了防火措施

English: 
Welcome to Catastrophic Science where we unveil life saving research that has resulted from catastrophes.
The terrorist attacks on the World Trade Centre resulted in it collapsing with surprising ease.
More than 2700 people died.
How to better construct buildings and prevent loss of life has occupied engineers ever since.
UNSW engineers have been working on the effects of heat on steel, high performance concrete and blasts in a city environment.
In the case of the World Trade Centre, the collapse was due to the design of the building.
They had very, very stiff beams, because they were very long beams
spanning right from the lift core in the building, out to the perimeter columns.
So you didn’t have internal columns that are going to compromise the ability to rent floor space.
The impact of the aircraft itself would have knocked the fire protection off.

English: 
And so when you got expansion of those beams in fire, they pushed against the very, very flexible columns
and knocked the columns out of alignment and eventually that led to the collapse.
And as a result of course, they
don’t design buildings that way anymore.
Fire research found that using less rigid steel beams supported by columns at regular intervals was preferable.
The beams buckle and sag but the columns hold them in place.
We’ve shown that because you get this sagging taking place and it’s allowable
that you actually don’t need fire protection, which can be up to 30% of the cost of the steel works, so that’s very substantial.
That’s quite a saving.
Yes. And the ground breaking research that we’ve done is in the connections
because we have to make sure that the connections are robust enough
when you’ve got the fire acting on
the structure to be able to hold that beam in place so you don’t get failure.
It keeps the fire in a compartment and it allows the occupants to get out of the building.
Now this isn’t the first time that terrorism has played a role in affecting future engineering.
Since the 1995 Oklahoma bombing where 168 people died and more than 680 were injured

Chinese: 
于是横梁因大火受热膨胀
挤压非常容易弯曲的柱子
并使其失去支持能力
最终导致大厦倒塌
由于这场灾难
设计师们不再沿用这种建筑设计方式
火灾研究发现
用一定间隔的柱子
来支撑刚性较小的钢梁是较好的方案
虽然此种横梁会弯曲下垂
但是这些柱子可以把它们固定住
我们证明了
因为梁发生了下垂但结构却很安全
所以并不需要防火措施
这可以节省高达30%的钢材成本
这是很大的一笔花费
这确实可以节省很大一笔钱
对
我们完成的另一项突破性研究是关于节点的
我们必须保证梁柱节点足够坚固
这样当火灾对房屋结构产生影响时
梁柱仍能固定而不会坍塌
这样可将火势控制在建造的某个部分
并可以让屋内的人离开建筑
恐怖袭击对未来工程产生影响已经不是首次了
1995年大阪爆炸案导致168人死亡
逾680人受伤

Chinese: 
此后研究人员开始研究
如何在人为爆破前安全地疏散建筑内的人员
我们已经做了很多关于超高性能混凝土的研究
这种混凝土的刚度为常规混凝土两倍
但是韧性坚硬度是常规混凝土的100到200倍
也就是说它能多吸收100到200倍的能量
并且承受住荷载以及支撑着整个结构
它的成本可能是常规混凝土的两倍
所以只需要确定哪一部分的结构最重要
比如重要建筑中地面层的柱子
同时我们也在研究建筑结构的连续性倒塌
这大概是指由爆炸引发的柱子移位后
建筑结构的表现是怎样的
建筑物如何在爆炸发生后
保持自身稳定并免遭受损区域影响
我们今天的研究成果将会被日后的工程师用到

English: 
researchers have been working on ways to allow buildings to be evacuated safely
before a controlled demolition.
We’ve been doing a lot of work on what’s referred to as ultra high performance concretes.
Now this is a concrete that is typically about twice as strong as conventional concrete
but it is also between 100 and 200 times tougher and that means that it can absorb 100-200 times more energy
and still resist the loads
and hold the structures up.
It’s probably twice as expensive as conventional concrete.
So you just need to identify what the most important structural elements are
for example ground level columns in important buildings
and we’ve also been working on what's referred to as progressive collapse of structures.
That’s very much how a structure
behaves after the removal of a column because of a blast.
How does the structure then perform
to protect itself from that event and the area of damage.
What we learn today will be utilised by engineers in the future.

Chinese: 
Brian  你的工作很刺激
事实上你就是在炸东西
是的  我的部分工作
就是在建筑物上进行爆炸试验
来看它们是怎么倒塌的
许多人用电脑来模拟
但并不总是那么精确
从工业角度看待爆炸同样相当重要
比如采矿业、油气行业
并且这一领域的研究正在蓬勃发展
据我所知  是有新的研究中心正在修建吧
是  我们正在UNSW
建立一个国家级物理爆炸模拟研究所
这样我们就可以在城市环境下进行爆炸模拟了
还有一点我们很想了解的问题是
当爆炸在城市某处发生后
它的冲击波在传播过程中
进而破坏城市的其他部分
是否会产生压强增大的反射
我们想要了解薄弱环节会在哪里出现
最重要的是
如果我们能够了解爆炸过程的所有知识
就可以更好的提高公众安全保障了
本片字幕由UNSW翻译专业学生 张齐 译制

English: 
Brian, you’ve got an exciting job, you actually just get to blow things up.
Yeah part of my role is to carry out blast testing on structures to see how they fail.
Computer simulations, which a lot of people do, are not always that accurate.
There’s a major emphasis on looking at blasts from an industrial perspective as well.
For mining and oil and gas industry.
And this area of research is gaining momentum, there’s a new centre I understand being built?
Yeah we have a national facility for physical blast simulation which is being built at UNSW
and we’ll be able to carry out blast simulations for city environments.
One of the issues that we’d like to understand
is if a blast is triggered in one part of
the city, when those waves propagate through the city
they can cause reflection and they
can increase the intensity of pressure in another part of the city
and we want to be able to understand where those vulnerabilities lie.
Ultimately if we understand the entire blast phenomena
public safety will be improved.
