In the course of our daily reporting, we often uncover unusual projects, places, or connections that don't make the final cut. Instead of keeping it to ourselves, we're pleased to share our weekly Architrivia.

Tetraphobia, the fear of the number four, weighs surprisingly heavily when it comes to the numbering of building floors in Asian nations. By the same token, the number eight has a similar impact on building design and functionality, though with the opposite connotation. Rather than supposedly bringing bad luck, the number eight is associated with prosperity in Chinese culture. Purported to be a particularly lucky day, August 8, 2008, saw droves of couples celebrating their nuptials in the hopes of forthcoming good fortune. And the craze surrounding the auspicious number can be felt in the structural skeleton of many of the world's tallest buildings.

The Jin Mao Tower, image by Flickr user Martin Howard via Creative Commons

The profile of Shanghai's Jin Mao Tower echoes that of a Chinese tiered pagoda. Its Postmodern embellishments become more intricate as the building rises, creating a series of flared volumes that gradually decrease in size. The 420.5-metre supertall comes to a close with four stepped mechanical storeys and a barbed spire. The impressive exterior of the building tells one story and the hidden interior components tell another.

The Jin Mao Tower, image by Flickr user Chris Bentley via Creative Commons

Similar to Kuala Lumpur's Petronas Towers, the number eight is ubiquitous in the design of the tower. The building has 88 floors divided into 16 segments, each one-eighth shorter than the one below. The building's octagonal concrete shear wall core is surrounded by eight exterior composite supercolumns and eight exterior steel columns. Connecting the columns to the core are eight two-storey-high outrigger trusses. Over 1,000 steel piles were driven 83.5 metres into the ground, which were the longest steel piles ever used for a land-based building at the time. The Jin Mao Tower has since been surpassed in height by its immediate neighbours the Shanghai Tower and the Shanghai World Financial Centre. 

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