The Good Samaritan Hospital in Puyallup, Washington required a West Wing Addition with a 30-ft excavation in loose fill on a crowded site immediately adjacent to the existing hospital and pedestrian walkway. The General Contractor for the project, DPR Construction, hired the design-build team of Ground Support PLLC and Malcolm Drilling Company Inc. to devise a cost-effective soil nail shoring system that would mitigate the cut face instability associated with the loose fills and yet address all of the design and site constraints.

• Permanent top-down shotcrete and epoxy-coated soil nails, 7,500 square feet of wall area, 30-ft deep excavation.
• New West Wing Addition for parking and central plant, situated in a small site immediately adjacent to the existing hospital, parking garage, and walkway.
• Extensive re-entrant corner conditions requiring splayed nails. Existing hospital and walkway foundations needed to be supported.
• Soil conditions consisted of 15-ft of loose fill underlain by dense glacial till.
• New heavy footing surcharge loads on the order of 400 kips each, dead plus live load, at various locations immediately behind the shoring walls.
• Large column loads, transverse floor slab moments, and in-plane seismic shear wall loads transferred to the top of the soil nail shoring walls throughout the perimeter of the walls.

• Cut face instability associated with fill soils prohibited the use of a typical shotcrete soil nail wall system with staged lifts that have no cut face support.
• The Owner's consultants initially concluded that the only other available shoring system was a relatively expensive anchored soldier pile system.
• The design-build team proposed the use of small 8-inch diameter face piles, 15-ft long, installed on 3-ft centers around the excavation perimeter to pre-support the fill soils prior to soil nail construction. The enhanced soil nail wall system was much less expensive than a conventional soldier pile system.
• The soil nail design was successfully adapted to the re-entrant corners, existing hospital and walkway foundations, new pin-piles, and existing ground anchor obstructions.