26 January 2010

The San Antonio retaining wall collapse – did the developer have a permit?

Posted by Dave Petley

Reports suggest that ground movement has ceased in the Rivermist subdivision, which suffered a fairly spectacular retaining wall failure over the last few days. Attention is now focussing upon that retaining wall – and in particular on why it failed. This is a pretty key issue given the potential liabilities and its magnitude – the wall is 1000 feet (>300 m long).

Press reports note two interesting aspects of this accident:

  1. The City of San Antonio has released a statement that says “The hillside collapse yesterday within the River Mist subdivision that damaged several homes was a result of an improperly constructed retaining wall, as well as improper compaction of fill on which homes were constructed by the developer, Pulte Homes. The developer did not obtain the required City construction permits for the retaining wall that collapsed.”
  2. Some reports suggest that this is the second time a retaining wall has failed at this site: “One neighbor who was among the first homebuyers in the subdivision set among rolling hills on the outskirts of San Antonio said he was initially told no homes would be built on the crumbling ridge because it was too steep. Romeo Peart, 32, said one retaining wall failed several years ago before the current one was built and homes were constructed above it” (Washington Post).

I should also add that I am not sure that this is a particularly simple retaining wall failure, based upon the image below (from here):

In particular, it appears that the slope / small retaining wall below where the man in the green jacket and hat is located has also failed. I wonder why?

Finally, I thought I’d embed this video, at least in part for the picture shown before the video starts, which is a somewhat surprising image in my opinion:


The video itself provides an interesting overview and a verification that a section of the wall had needed rebuilding on a previous occasion.