Naval Square Biddle Hall Annex and Townhomes
Developed as early as 1834, this historic site was home to the first US Naval Academy and the nation’s first retirement home for sailors and marine. Toll Brothers redeveloped the site, including the historic Biddle Hall (circa 1833) as residential tonwhomes and condominiums.
The majority of the new buildings were designed for an allowable bearing pressure of 4 ksf and are supported on subsurface conditions consisted of up to 10 ft of sandy silt uncontrolled fill underlain by sandy silt, clay, and coarse sand.
In order to minimize the amount of over-excavation and to improve the bearing capacity of the supporting fills, Geopier technology was utilized for the heavily loaded 7 ksf spread footings and Rapid Impact Compaction (RIC) for 4 ksf continuous wall footings. The required 4 ksf allowable bearing pressure was confirmed with post- RIC borings. The system was selected in lieu of Deep Dynamic Compaction (DDC) to minimize noise and vibration levels. RIC helped to maintain a fast-track construction schedule and save excavation costs. Over 500 Geopier elements were installed immediately adjacent to the vibration sensitive 180-year old structure without issues. This system reduced cost, minimized risk, and maximized schedule.