Conventional methods to bring down a tall building are pretty primitive: wrecking balls, dynamite, or dismantling with external cranes. Yet as the height of skyscrapers has risen (the Burj Khalifa in Dubai is the tallest at 2,717 feet), along with the number of skyscrapers slated for removal, new ways are being sought to reduce the environmental risks and expense of demolishing them. Japan has been among the first to confront this problem on a large scale: It has almost 1,000 skyscrapers above 100 meters tall, and many of them are aging.
The answer, say building companies like Tokyo’s Taisei Corp, will be demolishing them from the inside out, reports the Japan Times. Taisei launched its "Ecological Reproduction System," or Tecorep that, unlike a conventional demolition, dismantles skyscrapers within the walls of the existing building. The process reportedly cuts down drastically on noise, dust, and carbon emissions (by using energy-generating cranes to lower the material). You can watch a surreal time-lapse video of a building disappearing floor by floor in the video above.
The method uses the building itself as a scaffolding. The floors and walls are stripped bare. Cranes are installed on the interior roof, and holes are punched through the concrete slabs on each floor. The roof is supported by temporary steel columns. As the building drops, floor by floor, massive jacks lower each slab to the ones below. A detailed look at the technique presented by Taisei at a recent conference on sustainable skyscraper cities is .
So far, Taisei has only used the technique on a handful of buildings in Japan, including the 455-foot-tall Grand Prince Hotel Akasaka, the tallest building ever demolished in the country, but other firms are using similar approaches to replace aging infrastructure. And the challenge will only grow. The number of buildings taller than 200 meters has almost tripled, to 756 since 2000, reports the Council on Tall Buildings and Urban Habitat. (PDF)