Category Archives: Driven Soil Nail Walls

Freddie Mac Ground Shoring FM6

First driven soil nail wall is allowed in Fairfax County, VA

For the Freddie Mac Expansion project in McLean, VA, L.F. Jennings (G.C.) selected Subsurface Construction to design and install the ground shoring system around the perimeter of the site. Fairfax County has a shoring geotechnical review board with strict guidelines for allowable soil properties used in shoring design.  We were informed by the project geotechnical engineer that the review board never allows soil properties other than those stipulated by the board.

Always looking to innovate, T.J. Ju, P.E., Chief Design Engineer at Subsurface, made a compelling argument by presenting verifiable historical data and research results to the review board and convinced them to allow alternative soil properties that more closely matched the existing subgrade conditions found on site.  In conjunction with this data, Subsurface developed a program to verify the assumed properties by testing the soil at every lift and sending data to the client.  As a result, we were able to utilize our Driven Soil Nail System, developed by our company, which saved the owner time and money.

By working in close conjunction with the grading contractor, we were able to install as much as 1,300 sq. ft. of shoring in a single day, and completed the shoring installation 2 weeks ahead of schedule.  Innovation is a hallmark of our company and we are pleased to be a part of this progression for soil nail wall design in the Fairfax County region of Virginia.

Subsurface South Carolina Construction News

Subsurface is featured in SC Construction News

Engineers build successful Carolinas shoring construction business with participation of employee owners

South Carolina Construction News special feature

Formed in 1995 by three engineers, two structural and one geotechnical, Subsurface Construction Company LLC has grown over time to two regional offices, a staff of 35 and the capability of handling multiple, complex shoring and deep foundation projects at once.

The three founders started in the business as consulting engineers in Raleigh, NC, designing shoring systems for installation by contractors. Greg Sullivan, P.E., Subsurface’s managing member, says the group recognized that there were very few shoring contractors in the area, saw the market need, and launched Subsurface.

“We began in the shoring construction business by installing our driven soil nail walls, a unique shoring system that was developed by our company,” he said.

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