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  • By 2050, the world's population is expected to soar to almost 10 billion people, and two-thirds of us will live in cities.

    到 2050 年,全球人口預計將飛速成長到將近 100 億人,而超過三分之二會居住在城市。

  • Space will be at a premium.


  • High-rise offers a solution, but concrete and steel, the materials we currently use to build high have a large carbon footprint.


  • An answer might lie in a natural material we've used for millennia.


  • Our view is that all buildings should be made of timber.


  • We think that we should be looking at concrete and steel like we look at petrol and diesel.


  • I think it's very realistic to think that someone will build a wooden skyscraper in the coming years, there's a lot of potential that's unrealized for using timber at a very large scale .


  • Throughout history, buildings have been made of wood.


  • But it has one major drawback: it acts as kindling.


  • Fire has destroyed large swathes of some of the world's great cities.


  • But by the early twentieth century, the era of modern steelmaking had arrived.


  • Steel was strong, could be moulded into any shape and used to reinforce concrete.


  • It allowed architects to build higher than ever before.


  • So why, after more than a century of concrete and steel, are some architects proposing a return to wood?


  • If concrete were to arrive as a new material on Dragon's Den, if you were to pitch it and say, "I've got this brand-new material. It's liquid, and you can pour it into any shape and it'll solidify."


  • That sounds great.


  • But when you say, "We need a whole new fleet of trucks to move it around, and actually, when it solidifies, it's not strong enough. We have to stick this other stuff in it called steel."


  • I don't think it would be a compelling case.


  • Concrete and steel are costly to produce and heavy to transport.


  • Wood, however, can be grown sustainably and it's lighter than concrete.


  • And crucially, as trees grow, they absorb carbon dioxide from the air, locking it into the timber.


  • One study showed that using wood to construct a 125-metre skyscraper could reduce the building's carbon footprint by up to 75%.

    有份研究顯示,使用木材建造一棟 125 公尺的高樓能減少該建築高達 75% 的碳足跡。

  • Regular timber isn't malleable like steel or concrete, and isn't strong enough to build high.


  • But engineers have come up with a solution: It's called cross-laminated timber, or CLT for short.

    但是工程師找到了解決方法:這叫做交錯層壓木材,簡稱 CLT。

  • It's basically a new material, even though the underlying material is something we've used for millennia.


  • It's cross-laminated so the layers of wood are glued at 90 degrees to each other.


  • That makes for a very, very stable material.


  • CLT is light and it's comparable in strength to concrete and steel, but how does it cope when burnt with a high heat source?

    CLT 很輕,而且堅韌度和鋼筋水泥相當,但是遇到高溫怎麼辦呢?

  • Charred wood is extremely insulating: that's the tree's natural protection against a forest fire.


  • It chars, it loses some of its structural mass, but when you remove the source of flame, it extinguishes itself.


  • When steel gets hot, it gets a bit softer.


  • We've actually seen some steel roofs collapse in fires where wooden roofs have not.


  • London architects Waugh Thistleton are already designing buildings with this new kind of timber.

    位於倫敦的建築事務所 Waugh Thistleton 已經開始用這個新木材設計建築。

  • There's a CLT building behind, where the timber building sits behind timber clad, and then there's a really simple galvanized steel walkway.

    這裡後方有個 CLT 建築,全由木材建造,然後這邊是一個很簡當的,經過鍍鋅防鏽處理的走道。

  • Cross laminated timber is a material we work with a lot.

    我們常使用 CLT 這個材料。

  • Once these panels arrive on site, we're building a floor a week, at least.


  • So this is incredibly fast, maybe twice as fast as concrete.


  • Because when you build a concrete building--what we call concrete buildings--are actually floor slabs and columns.


  • When we build a cross laminated timber building, it's building floor slabs, all the external walls, all the internal walls, the lift cores, the stairs, the stair cores, everything is made of timber, so these are like honeycomb structures.

    可是,當我們建造一個 CLT 構造時,所有的元素,包含地板、所有的內外牆所以整個建築像是個蜂巢式的結構。

  • Andrew and his colleagues designed Britain's first high-rise wooden apartment block, and have recently completed the world's largest timber-based building.

    Andrew 和他的同事們設計了英國第一批木製公寓大樓,最近也完成了全世界最高的木製大樓。

  • Behind these bricks is a timber core made from more than 2000 trees, sourced from sustainable forests.

    這些磚頭後面是木材基底,從超過 2000 棵永續森林的樹木而來。

  • And this London practice is not alone in advocating the use of CLT.

    而這家位於倫敦的建築事務所不是唯一倡議使用 CLT 的公司。

  • Ambitious wooden high-rise buildings are also being constructed in Scandinavia, central Europe and North America.


  • As yet, nobody has used CLT to build beyond 55 metres.

    目前為止,還沒有超過 55 層樓高的 CLT 大樓。

  • But Michael Ramage's research centre in Cambridge working with another London practice has proposed a concept design of a 300-metre tower, to be built on top of one of London's most iconic concrete structures-- the Barbican.

    可是 Michael Ramage 位於劍橋的研究機構和另一家倫敦的事務所,一起設計了一座 300 公尺高的塔的藍圖,預計加蓋在倫敦其中一座最具代表性的水泥建築——巴比肯藝術中心——之上。

  • The way we've engineered the Oakwood Tower is to look at the global structure: Is it stable, and would it stand up?


  • We believe the answer is yes.


  • The columns at the base of the Oakwood Tower would be about 2.5 meters square, so that's solid timber, made of small elements glued together.

    橡木塔最底部的柱子大約長寬 2.5 公尺,全部以實木膠和製成。

  • I think we'll probably see incremental increases from the current height of about 50 meters, and at some point, someone will make a step change, probably to about 100 meters.

    我認為未來木製建築在高度上會有不斷的突破,可能可以再高 50 公尺,甚至在將來某個時刻有人會有辦法直接再突破 50 公尺,比現在多 100 公尺高。

  • Making that jump in height will be a difficult sell.


  • The cost of building wooden skyscrapers is largely unknown, but those costs could be reduced by prefabricating large sections of buildings in factories.


  • And city-dwellers will need to be persuaded that CLT does not burn like ordinary wood.

    此外,也必須說服城市居民 CLT 不會像一般木材那樣著火。

  • As an attractive, natural material, wood is already popular for use in low buildings.


  • If planners approve, it could rise to new heights.


By 2050, the world's population is expected to soar to almost 10 billion people, and two-thirds of us will live in cities.

到 2050 年,全球人口預計將飛速成長到將近 100 億人,而超過三分之二會居住在城市。

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木材在未來可能是摩天大樓的主要建材 (Wooden skyscrapers could be the future for cities | The Economist)

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    Rachel Kung 發佈於 2018 年 06 月 06 日