Could we build a wooden skyscraper? - Stefan Al

翻译人员: Sabrina Wang 校对人员: Helen Chang

Towering 85 meters above the Norwegian countryside,

85米高耸立于挪威乡间的 米约萨塔 (挪威语: Mjøstårnet)

Mjøstårnet cuts a sleek shape in the rural skyline.

是乡村天际下一座 精致优美的建筑设计。

Housing 18 stories of restaurants, apartments, and hotel rooms,

这座有18层楼的餐厅、公寓 和酒店客房的此一现代建筑

this modern building might seem out of place.

可能显得有点格格不入，

But a deeper look reveals it actually blends in quite well

但深入了解后发现 它实际上相当好地融入了

among the forested farmlands.

周边的森林与农田之中。

This is likely because Mjøstårnet is the world’s tallest wooden building,

这可能是因为米约萨塔 是世界上最高的木制建筑,

made almost entirely from the trees of neighboring forests.

几乎全由邻近森林的树木所制成。

Until the end of the 20th century,

直到20世纪末，

engineers thought it was impossible to build

工程师们一直认为不可能 建造一座超过六层楼高的木制建筑。

a wooden building over six stories tall.

Traditional boards of lumber were fairly strong against forces

传统的木板能够坚守对抗

与木材纤维生长方向平行的力量。

parallel to the wood’s fiber growth.

But they were vulnerable to forces applied perpendicular to this direction.

但它们对于从垂直方向 所施加的压力很脆弱——

As a result, wood lacked steel’s tensile strength

所以木材缺乏钢铁的抗拉强度

or concrete’s compressive strength—

或混凝土的抗压强度，

each necessary to support tall buildings

而这些都是支撑高层建筑

and battle the powerful winds found at high altitudes.

和对抗高海拔地区强风所必需的。

But the early 1890s saw the invention of glue laminated timber, or glulam.

但在1890年代初 发明了胶合板，又称胶合木。

And a century later, engineers developed cross-laminated timber, or CLT

一个世纪后，工程师开发了 交叉层压木材，或称CLT。

These new wooden materials start out like all other lumber;

这些新的木质材料 开始时和其他木材一样；

a freshly cut log is sawed into smooth uniform boards of wood.

刚砍下的原木被锯成光滑均匀的木板。

Then, in the case of CLT, the boards are glued together in alternating orientations

然后制成CLT，就是把木板 以纵横的方向交替粘在一起。

with each layer set at 90 degrees to its neighbors.

每一层设置为90度与其相邻。

The resulting material benefits from wood’s structural rigidity

由此产生的材料得益于木材

在各个方向的结构刚硬度。

in every direction,

allowing it to mimic the compressive strength of concrete

使其能具有像混凝土那样的抗压强度，

and bear loads up to 20 times heavier than traditional lumber.

并承受比传统木材重20倍的负荷。

Glulam on the other hand, glues boards together in the same direction,

而胶合木则是将板材 沿同一方向粘合在一起

forming massive beams with tensile strength comparable to steel.

形成巨大的横梁， 其抗拉强度可与钢铁相媲美。

Glulam isn’t as versatile as CLT,

胶合板不像CLT那样用途广泛，

but its incredible strength along one direction makes it superior

但沿着同一个方向时， 却具有令人难以置信的强度

for load-bearing beams and columns.

使它在承重梁和柱子方面更有优势。

These engineered forms of wood could finally compete with traditional materials

这些经过工程设计和改造过的木材， 最终可以与传统材料竞争，

while also bringing their own unique set of advantages.

同时也带来了它们 自己独特的一套竞争优势。

At one-fifth the weight of concrete,

CLT的重量只有混凝土的五分之一，

building with CLT requires smaller cranes, smaller foundations,

使用CLT的建筑需要用的 起重机和地基比较小，

and fewer construction workers.

需要用的建筑工人比较少。

While concrete has to undergo a time-intensive process

混凝土必须经过一个时间密集的

of casting and curing in a mold,

铸造和在模具中固化的过程，

timber can be shaped quickly using computer directed cutting machines.

而木材则可以使用计算机 直接操控的切割机，快速成型。

And where concrete requires certain weather and timing conditions

混凝土需要特定的天气和时间条件

to be poured on site,

才能在现场浇筑，

engineered wood can be prefabricated in a factory,

而工程木料可以在工厂里预制，

creating standardized parts with clear instructions for assembly.

形成标准化的部件， 有明确的组装说明。

Taken together, these materials allow for faster and quieter construction,

综上所述，这些材料 可以使施工更快、更安静，

with more biodegradable materials and less waste.

使用更多的可生物降解的材料， 产生更少的废料。

Once constructed, CLT and glulam buildings are also more resilient

一旦建成，使用CLT和胶合板的建筑

对一些自然灾害的抵御能力也会更强。

to some natural disasters.

An earthquake can crack concrete, permanently weakening an entire structure.

地震会使混凝土裂开， 永久性地削弱整个结构。

But cracked wood panels can be easily replaced.

但是，开裂的木板可以很容易被替换。

The same is true for fire safety.

消防安全方面也是如此。

As temperatures rise in a CLT building, the material’s outer layer will char,

在CLT建筑中，随着温度的升高， 这种材料的外层会烧焦，

insulating the inner layers for up to three hours.

从而产生对内层的隔热， 长达三个小时之久。

This is more than enough time to evacuate most buildings,

这段时间对于疏散大多数 建筑物来说是绰绰有余的，

and once the smoke has settled, charred panels can be swapped out—

而且一旦烟雾消散， 烧焦的面板可以被换掉，

unlike melted steel beams.

不像熔化的钢梁。

But perhaps the biggest benefits of CLT and glulam

但CLT和胶合板最大的好处

are outside the construction site.

也许在建筑工地之外。

Building construction is responsible for 11% of annual global carbon emissions,

建筑施工占全球年度 碳排放量的11%，

and the production of steel, concrete, iron, and glass

而钢铁、混凝土、铁和玻璃的生产

are major contributors to that figure.

是这一数字的主要贡献者。

Timber, however, is a renewable resource that can be made carbon-neutral

然而，木材是一种可再生资源，

如果种植树木来取代被砍伐的树木， 就可以实现碳中和。

if trees are planted to replace those cut down.

Wood also has low thermal conductivity,

木材还具有低导热性，

making it easier to heat and cool buildings with less energy waste.

使其更容易为建筑物供暖和制冷， 减少能源浪费。

Despite these advantages, CLT requires vastly more lumber

尽管有这些优优势，CLT所需的木材

要比传统的木制结构多得多。

than traditional wooden construction.

And when compared in similar quantities,

而在类似数量的比较中，

neither CLT or glulam is as strong as steel or concrete.

CLT或胶合木都没有 钢筋或混凝土那么坚固。

Even Mjøstårnet isn’t made entirely of wood,

即使是Mjøstårnet 也不完全由木材制成，

as it contains concrete slabs to reinforce the upper floors.

因为它包含了混凝土板 来加固上部楼层。

Taken together, it’s unlikely that a purely wooden structure

综上所述，纯粹的木质结构不太可能

would be strong enough to support a 40-story building—

有足够的强度来支撑40层的高楼 —

the minimum height for a formal skyscraper.

这是正式摩天大楼的最低高度。

But even if only buildings under 30 stories were built from wood,

但即使只有30层以下的建筑 是用木材建造的，

it would reduce the carbon footprint of those structures by more than 25%.

它也会使这些建筑的碳足迹 减少25%以上。

So no matter how tall these wooden buildings rise,

因此，无论这些木制建筑有多高，

each one contributes to the health of our concrete jungles.

每一栋都能对我们所处的 水泥森林的健康做出贡献。