Some of the latest info that came out is that the retaining wall in question did not have a permit from the City for its construction.
Dave’s Landslide Blog has some nice info on the fiasco, it has even attracted some comments from affected residents. He noted a strange lineation on an old image in Google Earth. I’m not sure I would agree that it was related to a slope or wall failure, it looks more like water draining down the street from someone washing their car or something. (Photo by Rodolfo Gonzalez – American-Statesman)
The Eng-Tips geotechnical forums have a few threads on the failure as well. A lot of arm-chair geotech going on there, here is the best thread I’ve come across. While we’re doing the arm-chair thing, that retaining wall doesn’t look like much of a wall to me, more like grouted rip-rap (see closer photo below).
Photo by Rodolfo Gonzalez – American-Statesman
Map of Failure Location
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Many waterfront properties all over the world having retaining walls or seawalls are aging to the point of needing repair or worse, replacement. Failure to provide proper weep hole relief has resulted in water being trapped behind the wall causing erosion, pressure, and wall failure.
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