Mosaic at Merrifield is a 31-acre mixed-use development that includes retail, commercial, residential, office buildings, movie theater, hotel and two parks. The Parcel B 200,000 sf development includes a new Target store on top of a two story precast parking garage and ground floor mixed-use retail.
Parcel B was found to have two to eight ft of undocumented fill consisting of lean clay and sandy silt with varying amounts of gravel and organics. The underlying residual soils consist of elastic silt, highly plastic clay and medium stiff to hard sandy silt. Column loads at the foundations range from 106 to 2213 kips.
The Geopier® system was selected to provide foundation support and control settlements for the heavily loaded columns and parking garage structure shear walls. A total of 1162 thirty-inch diameter Geopier elements were installed to depths of 10 to 26 ft to provide an increased bearing capacity of seven ksf. Special Dilatometer Tests were conducted to determine the depth of upper zone Geopier soil reinforcement required and evaluation of anticipated lower zone settlement to insure that total and differential settlements would be within the design one inch and half an inch, respectively.