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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 molded 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 then 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 then, 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-meter 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 it 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.


  • And 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, you know, a floor a week, at least.


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


  • Because when you build a concrete buildingwhat 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

    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、升降機槽、樓梯、樓梯間等,

  • everything is made of timber, so these are like honeycomb structures.


  • 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 2,000 trees, sourced from sustainable forests.

    這些磚頭後面是木材基底,從超過 2 千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 meters.

    目前為止,還沒有超過 55 層樓高的 CLT 大樓。

  • But Michael Ramage's research center in Cambridge working with another London practice has proposed a concept design of a 300-meter tower,

    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,

  • to be built on top of one of London's most iconic concrete structures, the Barbican.


  • The way we've engineered the Oakwood Tower is to look at the global structure.


  • And 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.

    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。

  • And, at some point, someone will make a step change, probably to about 100 meters.

    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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