950 Rose Avenue is the address of a new 36,000 sf Recreational Equipment, Inc. (REI) store. The store will feature a rustic yet modern design utilizing reclaimed wood and brick and contemporary vertical and etched metal paneling. Entrances will be framed by large wood and steel trellises.
Subsurface conditions at the site consisted of 3 to 14 ft of soft to medium-stiff clay fill, loose to medium dense silt and silty sands to depths of 30 ft, and decomposed rock.
The fill soils were easily improved using Geopier Rammed Aggregate Pier® elements to support the building foundations. However, the real challenge was to develop a cost-effective way to limit differential settlement where the REI store connected to an adjoining 19-story tower supported on drilled shafts bearing on rock.
The geotechnical engineer recommended the use of Geopier Rammed Aggregate Pier® elements to improve the fill soils so they could support footings designed for 6,000 psf for the main portion of the REI store.
For the interface with the 19-story tower, Ductile Iron Piles driven to decomposed rock were selected to support the loads from the south wall of the REI store adjacent to the tower. This approach eliminated the differential settlement concern at the interface between the two buildings.
GeoStructures, Inc. installed 159, 30-inch Geopier® elements to provide ground improvement across the majority of the site and 38 Ductile Iron Piles along the south wall of the store. Being able to work with one design/build contractor that could deliver multiple solutions allowed the team to provide a complete foundation system solution economically and on schedule.
The Ductile Iron Pile solution consisted of 118 mm diameter piles with 7.5 mm wall thickness designed to terminate on decomposed rock. The piles were designed for a working load of 40 tons.
A total of 38 Ductile Iron Piles were installed in 2 days. Pile lengths ranged from 27 to 58 ft.