High school teams at George Washington Carver Center for Arts & Technology near Baltimore will eventually have new athletic fields on which to play after completion of a 5,500 square foot retaining wall from design-build contractor GeoStructures.
While conventional construction systems may call for a post-and-panel or a tieback wall, GeoStructures took a different approach because of the site’s proximity to adjacent properties and its limited easements for wall construction. The company chose a soil nailing system involving top-down excavation on five-foot increments, installation of 230 epoxy-coated soil nails, application of shotcrete for temporary confinement of the soil between nails, and then attached precast concrete panels from the bottom up.
“Carver exemplifies the idea that there are unique challenges at every construction site that call for innovation,” says Charlie Carey, General Manager of the Earth Support Group at GeoStructures. “The challenge consisted of building a 15-foot high wall with a sloped surcharge in a cut condition that had easement restrictions behind the wall, which eliminated the ability to use tie backs. The soil nail wall solution was able to be built faster and utilized precast concrete facings that resulted in a better appearance.”
What helped speed up the construction process is the patented hardware used to attach the precast panels to the soil nails. With built-in versatility in all directions, the galvanized connections allowed a fixed dimensioned concrete panel to be attached easily to the soil nails.
“There is a learning curve for us because we’ve never built a soil nail wall,” states Tiffany Burket, project manager for general contractor American Infrastructure, “but everything is proceeding well and the site work should be done in time for the school to open by fall 2012.”
Other contractors on the project are Grimm & Parker Architects, structural engineer KCI Technologies and geotechnical engineer D.W. Kozera, Inc.