Demolishing Outdated High-Rises With a Sleight of Hand
新方法拆大樓 乾淨又安靜
By Henry Fountain

TOKYO – There are many ways to demolish a building, and some of them are spectacular: blowing it up from the inside so it collapses on itself, or smashing it to bits with a two-ton wrecking ball.
拆大樓有許多方法，有些相當壯觀：從建物內部引爆，讓它自行崩塌，或以拆屋鐵球砸成碎片。

But in this packed city with outdated high-rises and tough recycling and environmental restrictions, Japanese companies are perfecting what might be called stealth demolition. Some tall buildings are dismantled from the top down, the work hidden by a moving scaffold, others from the bottom up, the structure being slowly jacked down.
但在舊大樓林立的東京，資源回收及環保法規嚴格，日本公司發展出或可稱為「隱密拆除法」的技術。有些大樓從頂樓拆起，工程藏在一組移動式鷹架下進行；另有些大樓則從底層往上拆，整棟建築被千斤頂托住，慢慢拆除降低。

At times the techniques seem to defy gravity, for although the buildings appear intact, they slowly shrink. The methods, which make for a cleaner and quieter work site, may eventually find favor in other cities as aging skyscrapers become obsolete and the best solution is to demolish and rebuild.
這些技術有時似乎在對抗重力，因為大樓看來完整卻慢慢變矮。當今許多摩天大樓老舊過時，最佳處理辦法是拆除重建，這套讓拆除現場更乾淨、更安靜的方法，或許終將受到其他城市喜愛。

The latest Tokyo high-rise to get the stealth treatment is the Akasaka Prince Hotel, a 40-story tower overlooking one of the city’s commercial districts. Since last fall, it has been torn apart, floor by floor by hydraulic shears and other heavy equipment. It has been shrinking by about two floors every 10 days; this month it will be gone, to be replaced by two new towers.
東京以這套隱密工法拆除的最新案例，是樓高四十層、俯瞰東京市一商業區的赤王子飯店。從去年秋天起，該飯店以油壓剪切機等重機具逐樓拆除，約每十天拆兩層，將在本月完工，原址將新建兩棟大樓。

Hideki Ichihara, a manager with Taisei Corporation, which developed the system, said the technique had environmental benefits and allowed for more efficient separation of metal, concrete and other recyclable materials. Another advantage is visual: The vanishing building looks normal for as long as possible. “We want people not to really see the demolition work,” he said.
發明這套拆除系統的是大成建設公司，經理市原秀紀說，這項技術有環保上的優點，且可更有效地將金屬、水泥和其他可回收建材分開。另一好處顯而易見：盡量延長拆除中大樓外觀看來如常的時間。他說：「我們希望人們不會親眼見到拆除工作。」

The hotel’s top four floors were shrouded in a scaffold that hung from the intact roof and was covered in panels that mimicked the facade. When the two floors were gone, the roof-and-scaffold cap slowly descended, thanks to computer-controlled jacks on each of 15 temporary columns. Then the columns were lowered into new positions, and the workers started taking apart the next two floors.
赤王子飯店的最上面四層樓拆除時，是藏在一個從完整的頂樓吊掛下來的鷹架罩中，外層覆以與大樓外觀一致的嵌板。拆了兩層後，由於大樓內部的15根臨時支柱上都有電腦控制的千斤頂，鷹架罩會慢慢下降，接著柱子會降到新位置，工人則開始拆除接下來的兩層。

The cap helps keep noise and dust down compared with more conventional methods of demolishing tall buildings, which involve erecting a scaffold all the way up and around the structure but leaving the top exposed.
傳統拆除法從底層沿建物四周往上搭鷹架、但讓頂樓暴露在外，相較之下，新技術的鷹架罩可降低噪音及灰塵量。

“All the work is inside the covered area,” Mr. Ichihara said. “The noise level is 20 decibels lower than the conventional way, and there’s 90 percent less dust leaving the area.”
市原說：「拆除工作全都在罩內完成。噪音比傳統拆除法低20分貝，灰塵外逸量也少了90%。」

Aside from the cap, though, the Taisei system is similar to other methods in that the structure is taken apart from the top down. Another Japanese company, Kajima Corporation, has developed a bottom-up approach, cutting a building’s columns at ground level and jacking the structure down as each floor is removed. Since all the demolition work is done on or near the ground, there is no need to place heavy equipment, or workers, at the top of the building.
然而除了這個特別的罩子外，大成這套系統跟其他拆除法類似，都是從頂樓拆起。另一家日本公司鹿島建設研發出從底部往上拆的工法，先把地面層的鋼柱截斷，用千斤頂托住，每拆除一層樓地板，就調整千斤頂讓整棟樓降下。由於拆除工作全在地面層或接近地面層完成，無需在頂樓配置重機具或工人。

“The idea is to keep the building as intact as possible,” said Ryo Mizutani, an official with Kajima, which in January finished demolishing a 24-story office tower, the Resona Maruha building, near the Imperial Gardens. Huge hydraulic jacks supported the building’s 40 columns. Workers cut 75 centimeters from each column, over and over, to allow the structure to be lowered slowly.
鹿島建設主管水谷良說：「我們的想法是盡可能維持建物的完整。」該公司在今年一月完成東京御苑附近24層的千代田辦公大樓的拆除工程。當時他們以巨型油壓千斤頂撐住大樓的40根柱子，工人則每次把每根柱子截短75公分，讓整個結構體慢慢降低。

By creating controlled work environments, both Japanese methods allow for on-site material separation for recycling. At the Akasaka Prince, Mr. Ichihara said, the sorting starts at the top, and the concrete and steel are brought down by separate cranes. With the Kajima bottom-up method, Mr. Mizutani said, all of the debris is created on the ground level, allowing for efficient sorting.
這兩種日本新技術都創造出控制得宜的工作環境，讓現場建材分門別類回收。市原說，在赤王子飯店，建材分類從頂樓開始，水泥和鋼筋以不同的吊車運下。水谷良說，鹿島公司由下而上的拆除法，廢材全在地面層產生，故可有效分類。

A 2002 Tokyo recycling law required that wood and concrete waste be recycled in addition to valuable metals like steel, aluminum and copper, even if the demolition contractors had to pay to do so.
東京2002年頒行的回收法規定，除鋼、鋁、銅等值錢金屬外，木材和水泥廢料也須回收，就算拆除商必須額外花錢也不得規避。

“People started to take recycling seriously,” said Tsuyoshi Seike, an associate professor at the Institute of Environmental Studies at the University of Tokyo. “And things have changed quite drastically with demolition.”
東京大學環境研究所副教授清家剛說：「從那時起，人們開始正視回收，拆除工作如今已徹底改變。」

Mr. Mizutani said his company’s method had an added advantage in that hazardous materials like asbestos did not have to be removed from the site separately, before the structural demolition began. Rather, as the materials are stripped from each floor they can be left there until that floor reaches the ground and they can be safely carted away.
水谷良說，鹿島公司的方法有一項優勢，就是石棉之類有毒建材無需在結構拆除工程開始前，先從現場單獨運走，可在從每層樓拆下來之後留在現場，待該樓層降至地面層時，再用貨車安全運走。

But the Kajima bottom-up method has one major disadvantage: In earthquake-prone Tokyo, a building that is cut loose from its foundation could easily topple when the ground shakes. The company’s solution is to build temporary concrete structures, about three stories high, within parts of the building’s steel frame. Locking devices that would activate in an earthquake would tie the frame to the concrete structures, presumably keeping the building stable.
但鹿島公司由下而上的拆除法有個大缺點：在地震頻繁的東京，從地基拆起的大樓在地面晃動時容易倒塌。該公司的解決辦法，是在大樓部分鋼骨結構內打造一些約三層樓高的臨時水泥結構，在地震時啟動鎖定裝置，把鋼骨和水泥結構綁在一起，理論上可穩住大樓。

A building that is 30 or 40 years old should have many years of life left, if properly maintained. The Empire State Building, for example, is 82 and doing just fine after major renovation work. But the Tokyo buildings fell victim to a bull market for demolition.
一棟30或40年的大樓如果妥善維修，應該還能屹立多年。以美國紐約的帝國大廈為例，已落成82年，在大翻修後目前狀況良好。但東京許多大樓已成為拆除市場欣欣向榮下的犧牲品。

“There are many ways to renovate,” Dr. Seike said. “But with buildings in the middle of Tokyo, they think it’s better to demolish.”
清家剛說：「建物翻新的方法很多，但就東京市中心的高樓而言，他們認為還是拆了重建得好。」

原文參照：
http://www.nytimes.com/2013/06/18/science/tricky-ways-to-pull-down-a-skyscraper.html

Multimedia：Undoing a Skyscraper
http://www.nytimes.com/interactive/2013/06/18/science/0618-demolition.html

Video：How Do You Make a Building Disappear? Henry Fountain describes two unconventional demolition methods pioneered by the Japanese
http://nyti.ms/11tFUgc

紐時中文版翻譯：
http://cn.nytimes.com/science/20130619/c19demolition/zh-hant/

2013-07-02聯合報/G5版/UNITEDDAILYNEWS 馮克芸譯 原文參見紐時週報十版