At 1:51 p.m. EDT on August 23, 2011 — two years ago today — a rare earthquake shook the East Coast, rattling buildings from Canada to Georgia. The 5.8 magnitude quake was mild as earthquakes go, but it shed light on geotechnical engineering here in the Southeast. The two-year anniversary seems like a fitting occasion to launch the Foundation Repair Services blog.

Boulder Wall at Boone, NC Condo Complex Survives Earthquake

As fate would have it, the FRS crew had just completed work on a boulder wall in Boone, N.C. when the earthquake occurred.

The parking deck at a condominium complex was perched over a steep slope where large boulders could come loose and strike the support pillars, causing the deck to collapse. Authorities condemned the parking deck until the problems could be fixed. Foundation Repair Services stabilized an existing concrete retaining wall by installing tiebacks. We then drilled rck anchors and installed a SPIDER net to secure the boulder wall. Spike plates were added to secure the entire system.

The earthquake happened the day after the spike plates were tensioned. Our crew was standing on the parking deck when the tremors started. The condos and parking deck began to rock back and forth. Due to the flexible SPIDER net and the secure bedrock anchors we installed, the structure was flexible enough to absorb the earthquake and strong enough that the boulders and parking deck columns were kept in place. The system had performed perfectly!

2011 Earthquake Highlights Importance of Rock and Slope Stabilization

The epicenter of the 2011 earthquake was Louisa County, Virginia in the Piedmont region, 38 miles northwest of Richmond. The quake was felt in more than a dozen states along the Appalachian Mountains. It was the largest earthquake east of the Rockies since 1897.

Landslides caused by the earthquake occurred up to 150 miles away. Previous studies of earthquakes had found no landslides occurring more than 36 miles from the epicenter of a quake with this magnitude. It’s a stark reminder that rock stabilization and landslide protection in North Carolina, Virginia and throughout the Southeast shouldn’t be ignored.

To learn more about rock and slope stabilization, contact us at:

Charlotte: 704-545-0206
Asheville: 828-274-2101
South Carolina: 803-802-2477