Eco-friendly Japanese demolition scheme slashes dust and noise

Passers-by in Tokyo's busy Akasaka district have started to notice something odd about a 40-floor hotel - it has shrunk to about half its original height.

Slowly but surely, and with none of the explosions or dust normally associated with the demolition of skyscrapers, the hotel is being torn down.

"In this demolition scheme, the building shrinks and disappears without you noticing," said Hideki Ichihara, manager of Taisei, the construction firm running the project.

The Grand Prince Hotel Akasaka was built in the 1980s, a gleaming, 140-metre symbol of a decade of extravagance when people almost had money to burn and Japan's red-hot economy powered the world.

Now it is shrinking: losing two floors, or 6.4 metres, every 10 days, said Ichihara.

The Japanese-developed Taisei Ecological Reproduction System (TECOREP) is a new process designed to contain the noise and dirt of a demolition, and recycle the energy pent up in a tall building.

Engineers reinforced the top floor with steel beams and then effectively lopped it off, keeping it in place to be used as an adjustable lid that can be lowered down the building on an external support frame.