Sat, 06 Feb 2010 16:53:34 +0000

Anonymous said...

This type of retaining wall is built all over this area. It IS a gravity wall, the gravity structure happens to be at the bottom of the wall and goes in a backwards batter below the earth instead of forward making the wall sloped on the facade. The backwards batter/gravity device is made up of rip rap rock and possibly some concrete slurry. That is the theory anyway. The guys who build these walls boast about the speed of which they build them, mostly with very cheap (but stable) limestone like what you see in the photos and VERY cheap labor. They generally pour a rough concrete beam at the bottom to start the stacking on the taller walls.
I worked on a project in this area for a large resort where there is
93' of grade change from the front entry to front door. The developer wanted to bench 650 or so surface parking spaces on that slope. So, there will be walls similar to these holding about 8 bays of parking up this slope with only about 8' from curb to top of wall! We went through hours upon hours of meetings with structural engineer and guys who build these types of walls. Structural engineer was against stacked stone gravity walls of course. The gravity wall builders had their own structural to stamp drawings.

We will see if it holds! The walls have been up for a year or so and there are MANY on the site. I think the tallest at about 30' holding up a POOL and spa. I think they are all built with a 12:1 batter.

SAN ANTONIO (AP) – A San Antonio planning official says a retaining wall designed to hold up the land beneath a group of homes that now sit precariously on a crumbling hilltop did not have a permit.

Planning Director Roderick Sanchez says Centex Homes was required to get a permit for the 1,000-foot-long stone wall used to shore up a hill where several homes were built – but no permit was acquired.

He says the builder’s parent company, Pulte Homes Inc., assured the city that it had a certified engineer design the wall and it was built to specifications.

But so far, Sanchez said Monday that the city has not seen any verification.

About 25 homes remain evacuated after a landslide that began Sunday threatened to collapse the wall and send several houses tumbling downhill.