Building topples over
Jearl Walker www.flyingcircusofphysics.com

Here are photos and drawings (sorry, I don't know who gets credit for them) that show a 21-story building after it fell over like a domino. If the building-to-building spacing had been small enough, there could have been a domino effect on a line of buildings. Thankfully, there was no such effect and no one was hurt or killed.
    An underground parking lot was being dug out on one side of the building, with the dirt piled on the opposite side. Thus there was a pressure difference on the two sides of the building, on the concrete pilings that secured the building in the ground: lower pressure on the dug-out side and higher pressure on the piled-up side.
When rain soaked the ground and also eroded the dug-out side, the pressure difference became so large that sone of the pilings broke and the building leaned toward the dug-out side, which bent and broke the rest of the pilings. In the latter photos, you can see those pilings --- some have horizontal breaks and other have breaks that travel across and down the piling. The latter broke while being bent.


 

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