The Parr Ford Auto Group proposed to construct a large automotive dealership in Bremerton, Washington. However, the project required excavation into a glacial till hillside for creation of building pad areas, with the wall line falling within 6 feet of Oyster Bay Avenue South.

The 1200-ft long shoring wall required a hillside cut ranging from 19- to 26-ft in height, resulting in roughly 23,000 square feet of excavated wall face. However, an additional 6-ft high cantilever was to be backformed and shotcreted along with the first lift of soil nailing, and subsequently backfilled to bring the wall up to the roadway grade behind the wall.

The Design Build team comprised of Ground Support PLLC and Malcolm Drilling Company Inc. developed a complete permanent shoring wall solution for less than $20 per square foot of wall face. The shoring wall is comprised of permanent epoxy-coated drilled soil nails and a permanent top-down shotcrete wall facing system.

The 6-inch thick wall facing was constructed with shotcrete in lifts from the top-down, and attached to the soil nails with a headed-stud type of connection. However, when the 6-ft high cantilever was combined with the first lift of shotcrete and nails, over 11 feet of shotcrete needed to be supported on the first row of soil nails. Therefore, additional strut nails, comprised of 12-ft long steeply inclined nails were installed along with the first row of conventional nails to provide the required vertical support.