In case you’ve been out of the country lately, Rivermist is the Northwest Side neighborhood where people saw huge cracks open in their backyards and a retaining wall collapsed Jan. 24.
Sweeney’s artwork is part of the Urban Landscapes exhibit on view at Palo Alto College Art Gallery through the end of the month.
Don’t worry, Centex. Sweeney has also made fun of President Bush. And he once created a postcard to Sam Houston from Davy Crockett on a fantasy vacation to Cancun: “Dude — This place is awesome .. met some chicks … Bowie puked in the lobby … Travis says hey.”
Nearly two months after a retaining wall split open at the Hills of Rivermist in San Antonio, Centex Homes submitted plans to the city for a new wall that is reinforced with concrete piers and will cost at least $4 million:
Centex Homes is hoping the third time’s the charm. This week it produced a preliminary design concept for a new retaining wall to replace one that collapsed in January in a Northwest Side neighborhood — which in 2007 replaced one that was not “performing to expectations.”
But homeowners say they are weary after two months of stress and uncertainty and are still on the fence about whether to trust that this latest fix will last.
The builder and developer of Rivermist and The Hills of Rivermist told the city it plans a wall 1,700 feet long. The new wall will be built in front of the existing retaining wall, and will include reinforced concrete piers driven 10 to 30 feet into the ground and reinforced concrete panels between the piers, Centex said in a news release.
The company will give the city formal engineering plans by April 30. It expects construction to take four to six months and cost $4 million to $5 million.
The original structure was a gravity wall, which relied on the heavy weight of stone and mortar to remain stable. But after the collapse, city officials inspected the wall and claimed it lacked a solid core of mortar, which makes the wall lighter — and unstable.
An interesting status report was posted online tonight by San Antonio officials who are examining the retaining wall collapse at the Hills of Rivermist. Officials met with local builders, who were told they must review all retaining walls built over the past three years that are more than four feet tall. The builders must make sure an engineer designed each wall and that the structure was built correctly. And the builders must pull permits for each wall by March 31.
The builders raised several concerns about the city’s permitting requirements, some of which were discussed in our story about the city’s lack of oversight of retaining walls. Here’s the complete status report on the city’s Web site:
Development Services, the Greater San Antonio Builders Association, and approximately fifty of its members met today to discuss the need for the public to feel assured retaining walls in San Antonio have been built correctly. At the meeting, Development Services discussed:
* The City’s building code requirements to obtain permits for retaining walls.
* Builders need to (1) identify all retaining walls over four feet and built during the past three years, (2) provide documentation the walls were designed by an engineer and built correctly, and (3) obtain permits for the walls by March 31st.
* Development Services will use the information to develop a tracking system for retaining walls.
At the meeting, the builders initially expressed that they did not believe all retaining walls require permits. In addition, since some of the walls were constructed several years ago, they were concerned about the challenges of finding documentation to satisfy the City’s permitting requirements. Finally, they expressed a need to amend the Unified Development Code to clarify permits are required during the site development stage of construction.
Development Services responded to the builders’ concerns by reiterating permits are required for retaining walls over four feet. The department will work in partnership with the builders to issue permits and to obtain documentation that attest to the safety of the walls by the end of the summer. Finally, Development Services agreed to explore an amendment to the Unified Development Code to reinforce the procedures for permitting retaining walls during all phases of construction; from land development to building development.
At the conclusion of the meeting, Development Services and the builders agreed it was important to restore the community’s confidence that existing retaining walls built in San Antonio are safe. Development Services will develop information bulletins and new applications to reinforce the procedures for permitting retaining walls related to new construction.
New documents offer more information about the retaining wall that collapsed at the Hills of Rivermist, a neighborhood in San Antonio built by Centex Homes. Comparing the wall’s engineering plans to a memo describing how the wall was actually built shows the retaining wall might have lacked crucial features:
- The original engineering plans for the wall, drawn up by Russell Leavens of Enterprise Engineers Inc., show the wall was designed as a gravity wall, which relies on its own weight to remain stable. The contractor that built the wall is the aptly named Gravity Walls Ltd., owned by Chun Lambert. We wrote this story about a city inspection that concluded the wall wasn’t built with enough mortar. Less mortar means less weight, which could destabilize a gravity wall. Lambert hasn’t returned our calls.
- After our story was published, city officials continued inspecting the wall. Development Services Director Roderick Sanchez wrote this memo last week laying out the reasons why he believes the wall can’t be patched up. Sanchez offers more details about how the wall wasn’t built to Leavens’ specifications. For example, the wall is missing a layer of limestone and fabric that was supposed to be set behind the structure to capture water and properly drain it through weep holes at the bottom of the wall.
“There are multiple reasons why the wall may have failed,” Sanchez concluded. It could have been a combination of design failure, construction failure, or soil failure beneath the wall, he wrote.
The memo was posted on a city Web page set up to provide daily updates about Rivermist. The city posts new information at the end of every business day.
I’m helping out with the coverage of the “slope failure” at the Hills of Rivermist, the neighborhood in San Antonio where shifting soil and a buckled retaining wall jeopardized homes. Here are some useful resources to learn more about what happened:
- Express-News photographer Jerry Lara shot recent aerial photos of the neighborhood showing the scale of the damage.
- Bing features a cool 3D map of the site, and in Google Earth you can view a series of aerial photos to see how the hillside was flattened and sculpted over time.
Google’s tutorial explains how to check historical imagery of an area. The wall collapsed where Treewell Glen curves into Valley Well:
Typing in an address of one of the affected homes, such as 12003 Treewell Glen, will zoom Google Earth to the spot. Then click on the clock symbol in the toolbar, and you’ll be able to view aerials dating back to 1995.
- This is a plat of the site filed at the Bexar County courthouse. It identifies the engineering firm that designed the neighborhood as Pape-Dawson Engineers, a well-known firm in San Antonio. Gene Dawson told me the engineering work for the retaining wall was done by another firm. The plat also shows there’s a sewer line under the area that collapsed:
Centex says it still doesn’t know what caused the slope failure.
You can search for and view plats, deeds, and other documents filed at the Bexar County courthouse for free at a Web page set up by County Clerk Gerry Rickhoff. The site requires you to register.
- City Manager Sheryl Sculley sent this e-mail chain to Mayor Julian Castro and the City Council explaining the city’s permitting process. Centex Homes says it was unaware a permit was required for a retaining wall.
- Centex released a public statement about the slope failure. “Centex has been focusing on stabilizing the homes and is now entering the investigation phase. We have retained several well-respected engineering firms and soils professionals to aid in our efforts to accurately determine the cause of the soil movement. We will not speculate on the underlying cause of the soil movement at this time, but will provide additional details when they become available.”
- On Twitter, the incident has its own hashtag: #slopefail, coined by police reporter Eva Ruth Moravec who was among the first reporters at the scene on Sunday. Props do have to be given to KSAT for their own hashtag — Eva said they came up with #sinkholegate.
- You can check the credentials for engineers in Texas at the Web page of the Texas Board of Professional Engineers. You can verify an engineer is licensed by searching here, or if you’re a data monkey you can download zip files of the entire roster of all engineers here. Disciplinary actions taken against engineers are listed here. You can browse the disciplinary actions, but they’re not easily searchable. You can search for a specific name by typing “http://www.tbpe.state.tx.us” in Google and then the name.
Feel free to get in touch with me with any tips or story ideas about #slopefail — here’s my contact page.
Updated 1-29-10: Two more useful Web pages that are new:
- Centex set up a Web page about the collapse. The company is posting announcements, a FAQ page, and a form that allows residents to pose questions online.
- The San Antonio Express-News set up a Web page with all our news stories, photos, videos, and graphics about the sliding hillside.