Press reports note two interesting aspects of this accident:
- 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."
- 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).
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.
Has there been any report as to what company was actually responsible for designing and installing the retaining wall?
ReplyDeleteAs a design engineer, I can tell you a retaining wall of this magnitude should have been designed by a structural engineer with geotechnical information from which to make his judgments. When it all comes out in the wash, I bet we'll find out either that the wall wasn't done by a licensed engineer or it was done by some incompetent. DJ
ReplyDeleteIs there another meeting set up for residents in the neighborhood? I live on Ranchwell Cove and am very concerned now about property values plummeting in this area. I keep on finding out after the fact that there were meetings. Any help would be appreciated.
ReplyDeleteYou know what Vern? Greed's a terrible thing, it'll eat you alive.
ReplyDeleteAs a wall contractor in Austin, I'd like to see design specifications for ANY gravity wall system. You have design criteria for MSE walls but I have yet to see any calculations that work for a gravity wall. Pictures of that wall show the base to be approximately 4' in width...Not even close to viable.
ReplyDeleteWhile the question of whether the wall was properly designed (and by whom) is important, construction methods are critical. For years many owners/developers have gotten away from having an engineer of record monitor the construction of their project, and it's particularly important when looking at critical elements such as a wall like this. One thing I noticed right off the bat is the presence of the partially undermined manhole structure sitting cockeyed in the one failure trench. I'm curious whether the outfall sewer from than manhole ran beneath the wall, and the trench was not properly backfilled. That very easily could have contributed to the extent of the failure.
ReplyDelete