The Florida Association of Court Clerks building underwent a renovation project that included repair of drywall cracks and other distress-related issues caused by structural settlement. Each of the nine interior columns had settled within the range of 1/2-inch to 2 1/4 inches. An evaluation of the structural details and existing soil conditions determined the probable cause of settlement to be insufficient footing design given the soils present on the site. The depth of problematic soils ranged from 6 to 14 feet, so a shallow fix was not practical. Due to the extent of information which the Association of Court Clerks processes and stores, shutting down the facility even temporarily for the repairs was not an option.
Helical piles were selected for their ability to achieve the design capacities of 20 kips with smaller, less intrusive installation equipment. The helical pile configuration consisted of 2 7/8-inch OD by 0.276-inch wall hollow round shafts with 8"-10" double-helix lead sections. The piles were installed with portable handheld equipment to at least 5,000 ft-lb of torque and the depths of approximately 20 feet. Four piles were installed at each of the nine column locations. Ultimate capacities of the piles, estimated by correlation to installation torque, were at least twice the design load. The piles were attached to the column footings with heavy duty retrofit/ side-load brackets. All work on the project was completed within 8-hour shifts at night to prevent interruption to daily operations within the building. The prep work, installation of 36 helical piles, back filling, and clean up took less than five days to complete and the renovation project continued on schedule.