Retaining Walls

  • More retaining wall problems discovered in a San Antonio subdivision

    After a towering retaining wall collapsed and threatened scores of homes last year in the San Antonio neighborhood of Rivermist, an obvious question arose: How safe were the untold number of other residential retaining walls in the city?

    Under city code, walls in San Antonio over four feet tall were supposed to go through a permitting process. But until Rivermist, that permitting process rarely happened in new subdivisions — despite the widespread use of large walls to sculpt hillsides in the rapidly growing Texas Hill Country.

    In other words, no one at the city could vouch for the safety of other retaining walls, many of which are 20 feet high or taller.

    After the collapse at Rivermist, the city announced that all tall residential walls built in the last three years had to be verified as safe by an engineer and permitted. So far, most walls have passed muster.

    But one subdivision with 14 retaining walls is still having problems.

    It’s called the Heights of Crownridge, located on the far North Side by the Crownridge Canyon Natural Area. Jen found out about it after a concerned resident emailed her photos of a long vertical crack in a huge wall in the middle of the subdivision.

    Jennifer and I had written a bunch of stories about the problems with retaining walls in San Antonio. After Jen got the tip, we drove to Crownridge over the weekend with baby Sophie sleeping in the car. The subdivision was unfinished — streets were completed but only a handful of homes had been built. There were no lawns. Just sun-baked dirt and rock.

    And there are a lot of tall retaining walls. The one the tipster alerted Jen to is huge:

    Retaining wall at the Heights of Crownridge in San Antonio

    And sure enough, there was a long, very noticeable crack on the northern section. This is part of the crack:

    Cracked retaining wall at the Heights of Crownridge in San Antonio

    Jen sent an open records request to the city for more information about what was going on at the Heights of Crownridge. A couple weeks ago we sat down in an office of the city’s Planning and Development Services Department to read a stack of letters and engineering plans related to all the retaining walls in the unfinished subdivision.

    No engineering plans had yet been received for the big wall we checked out. (I later interviewed Scott Rozier, the owner of Rosch Co., which built the wall with the crack. He stood by his work.)

    But there were problems with other walls. Going through the documents, Jen and I had a case of deja vu. It turned out some of the same people involved with the wall at Rivermist also designed and built a wall that later cracked at the Heights of Crownridge.

    Engineer Russell Leavens designed the Rivermist wall, and it was built by Gravity Walls Ltd. They also designed and built a different wall at Crownridge that suffered from a large crack and was deemed unsafe. This wall was on the southeast corner of the subdivision, which we hadn’t known about. Engineer Tim Theis determined that the wall had not been built according to plans.


    At Rivermist, city officials had also claimed that Gravity Walls Ltd. did not build the wall according to engineering plans.

    Theis mentioned problems with the particular type of retaining wall used in both subdivisions. Gravity walls rely on their sheer mass to remain stable. But once they’re built, it’s difficult for inspectors to make sure the walls were constructed right. That problem was noted at Rivermist and also at Crownridge.

    As we reviewed the documents, a city engineer who was handling the case came by the office. It turned out construction had been on hold at some lots for months as the concerns about the retaining walls were being sorted out.

    The pile of documents included maps showing the location of each retaining wall and who built it. Coupled with the info we learned from other documents and interviews, the maps helped me build this interactive feature that showed readers what was going on in the subdivision:


    View Retaining wall problems at the Heights of Crownridge in a larger map

    We could have cranked this story out faster if Jen hadn’t made the open records request. But the documents gave us details that we might not have otherwise known, such as the connection to Gravity Walls Ltd. Plus, we can post the paper trail online for readers to check out for themselves.

    It simply pays to dig up pertinent records … even if it slows you down.

  • City owned a faulty retaining wall

    Faulty retaining wall
    Photo courtesy of Ernest Ruiz

    After a tall retaining wall buckled in a San Antonio neighborhood, threatening dozens of homes, rancher Ernest Ruiz called us with a tip about another faulty retaining wall.

    Ruiz’s story had an interesting twist: The collapsed wall near his rural property hadn’t been constructed by Centex Homes or other homebuilders. This wall was owned by the city:

    From a mostly quiet tract of land surrounded by the hubbub of urban life, Ernest Ruiz has waged a nearly three-year fight against the city of San Antonio over the failure of a retaining wall.

    In the summer of the epically wet 2007, a city-owned retaining wall that sits between Pearsall Park and Ruiz’s South Side ranch collapsed during a rainstorm, sending dirt and debris onto his property and into Leon Creek.

    “There were rocks all over the place,” said Ruiz, a 72-year-old rancher who has been buying property in the area since the 1980s and now has about 265 acres that he calls Leon Creek Ranch. “When that rain came, it tore everything right down the middle.”

    While San Antonio rebuilt the damaged portions of the retaining wall and cleaned up its property, Ruiz said the city has done nothing to clean up his property, and he’s still trying to recover.

    Ruiz found it ironic that the city criticized Centex Homes for not pulling a permit for the wall at the Hills of Rivermist, while the city suffered its own wall failure.

    Jen’s story about the legal dispute featured some colorful details about the ranch — how Ruiz’s family likes to play cards on poker nights and fish for perch, and how the rumble of jets at Lackland AFB drowns out the country tunes from the AM radio in Ruiz’s Toyota pickup.

    I like articles that paint a scene for the reader. One way to do that is to write descriptions that engage all the senses — not just how something looks, but how it sounds and smells and feels. Jen’s story makes you feel like you’re sitting in the truck cab with the old rancher, going along for the ride.

  • San Antonio builders must check all retaining walls built in past three years

    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.

    Retaining wall at the Hills of RivermistThe 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.

  • Was cracked retaining wall built correctly?

    Engineering plans for retaining wall at the Hills of Rivermist

    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.

  • San Antonio officials paid scant attention to towering retaining walls

    Encino Ridge retaining walls in San Antonio

    Jen and I wrote a story that ran in Sunday’s paper and was posted online today about the lack of oversight of retaining walls in San Antonio. We looked at this issue after a retaining wall in The Hills of Rivermist, a neighborhood built by Centex Homes, split apart and jeopardized dozens of houses:

    Despite the growing popularity of towering retaining walls like the one that buckled last week, San Antonio officials have paid scant attention to the structures in residential subdivisions and can’t vouch for their safety.

    No one at City Hall tracked how many walls were built over the years as thousands of residents flocked to the Texas Hill Country and developers reshaped steep terrain for new homes.

    City inspectors never checked the walls.

    And, according to members of the real estate industry, it wasn’t widely known that a permitting process existed for tall retaining walls.

    “No one can find where the city has ever asked for or insisted on a permit,” subdivision developer Norman Dugas said. “I can’t find anyone who has ever gotten one.”

  • Retaining wall not built to engineering specifications

    Retaining wall at the Hills of Rivermist

    Jen and I wrote a follow-up story today about the sinking neighborhood in San Antonio called the Hills of Rivermist:

    The retaining wall that collapsed last week and jeopardized a neighborhood built by Centex Homes was built with less mortar than what engineering plans called for, according to city officials who inspected the wall Friday.

    “Staff determined that the retaining wall was not built in accordance with the design provided by (the) design engineer,” Assistant City Manager T.C. Broadnax wrote in an e-mail to his boss, Sheryl Sculley, Mayor Julián Castro and the City Council.

    “For example, the building plans for the wall show limestone mortared throughout the wall. Based on field observations of the failed portion of the wall, mortar was not installed according to the building plans.”

    There are many different types of retaining walls. The one at Rivermist is called a gravity wall, which relies on a heavy mass of mortar and stones to remain stable. So if a contractor skimps on the mortar in the core of the wall, the wall becomes lighter and it can become unstable.

    Here’s the city e-mail describing the lack of mortar inside the wall. The city also set up a new Web page that provides updates about Rivermist. Residents can also report concerns about retaining walls near their homes.

  • Maps, plats, and photos of the sinking neighborhood in San Antonio

    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:


    View Larger Map

    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:

    The Hills at Rivermist Plat

    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.