Delicate Demolition: The Clean, Green Way to Remove a Skyscraper
What goes up must come down. But with city centres becoming more congested, how do you demolish skyscrapers safely and efficiently? A Japanese construction firm has the answer…
Tokyo – capital of Japan and the world’s most populated city – is a sprawling metropolis that’s densely packed with buildings. Some streets are so tightly packed that if you open your arms, you can touch buildings on both sides simultaneously. This is why architecture favours tall buildings, because office towers need very little floorspace and can soar hundreds of feet into the sky.
But what happens when you need to bring down existing towers to make way for new ones?
With so little free space available, standard demolition procedures involving wrecking balls or explosives are out of the question. Unless of course you’re prepared to foot the bill for local evacuations, office relocations and the inevitable building repairs.
Instead, construction companies in Japan are trailblazing novel ways of bringing down high-rise buildings in densely populated areas – and most residents barely know it’s even happening.
The 40-storey Akasaka Grand Prince Hotel in Japan is currently being lowered from the top down by contractor Taisei Corp. It still has a roof, and it is shrinking by two floors at a time until it reaches the ground in May 2013.
The roof is supported by temporary structures and is lowered by jacks, with most of the work taking place in an enclosed space between the roof and scaffolding. This cuts down on noise and dust – reducing the impact on local residents and office workers. It’s kinder to the environment too.
However this is not the first time that this ‘jacking down’ method has been used.
Japanese construction firm Kajima Corporation used this technique – known as the Kajima Cut and Take Down Method – on its own Tokyo headquarters back in 2007. And in 2008, it used the process on two city towers which resulted in over 90% of the construction materials being recycled. Traditional demolition methods typically only recycle an average of 55%.
So gradual is the process that at the hotel site in Tokyo, a prominent point on the city skyline, residents and city office workers were surprised and completely unaware that the building was being demolished in front of their eyes.
With environmental issues high on the agenda, we could soon see much more of the Kajima jacking technique on buildings and office properties around the globe. So next time you pass that 1960s office block or tired-looking skyscraper, make sure you look twice – because it might be shrinking in front of your very eyes.