By Benjamin Cost
Shanghai, a city of over 20 million people and indomitable skyscrapers, is apparently giving indications that it’s eager to join Atlantis among the great cities of the world that sank into the ocean. The quake-evoking cracks in the pavement around the new Shanghai Tower project in Pudong (the soon-to-be “world’s tallest building”) have measured up to 8 m long and 4 cm wide, inciting a mild panic in Shanghai. Residents fear that sinking ground caused by densely-packed skyscrapers will be to blame for the city’s downfall.
Presumably to ensure that faults in the ground don’t morph into faults in their reputations, city officials have dismissed this notion:
The information office of the Shanghai municipal government updated its official micro blog on Thursday, and said the underground structural engineering of Shanghai Tower was completed at the end of last year, and the factors that caused the subsidence have been eliminated.
Ge Qing, design director of Shanghai Tower Construction and Development, also wrote messages on Sina Weibo, confirming all was safe and sound during construction of the base of Shanghai Tower.
Engineering experts said such “settlement” cracks were common anywhere in the world and had nothing to do with the weight or height of buildings.
“Groundwater and rainfall may be blamed for settlements, and the soft soil foundation in Shanghai is another reason,” said Liu Dongwei, chief architect of the China Institute of Building Standard Design and Research.
Surprisingly, this time, officials are not too far off (a rarity when you consider that authorities have a knack for blaming random acts of god for what is clearly human folly; ie. Beijing’s “fog”).
It has been known for quite some time that the rapidly rising Shanghai is also sinking into the ground – by seven millimeters a year to be exact. The particularly unstable Bund area has sunk approximately three meters over the last two decades.
The aforementioned cracks are a byproduct of preventative measures to the subsidence, which is brought about by shifting groundwater levels to facilitate industrialization:
Technology plays a big role in preventing the densely-populated city from being pulled into the ground. Data gathered by radar satellites make it easy to detect the slightest changes in elevation. And over 300 underground detectors in the city monitor changes to underground water levels. Hundreds of tons of water are injected each day to replenish underground aquifers and keep the city aloft.
And even city workers are doing their part to help with Shanghai’s ground troubles by sealing the cracks with cement (which kind’ve seems like putting a band-aid on a brain tumor, but still). Hopefully the underground aquifers will continue to keep Shanghai literally riding high and prevent it from becoming Shanglantis.