Thomasville Landmarks, Inc. recently purchased a historic warehouse located in downtown Thomasville Georgia to serve as their corporate headquarters. Their plan was to completely renovate and modernize the historic structure. A third party structural evaluation of the building revealed substantial settlement of the structure's foundation. To determine the cause of settlement a geotechnical investigation was performed and identified that the warehouse had been constructed atop a construction debris pit approximately 8 ft below existing grade.
CHANCE® Helical Underpinning systems were selected by the engineer of record to provide high-capacity piles to stop settling and foundation failure of the historic South Georgia structure. The helical piling system was installed by Mason Grady Foundations (MGF), a Certified Installer of CHANCE Helical Foundations Systems. The entire underpinning system was installed and the structure stabilized in two weeks.
The underpinning system consisted of thirty-five (35) CHANCE 2-7/8" Round Shaft Pipe Piles. Lead sections consisted of a 10", 12" helix configuration, installed to depths ranging from 12 to 20 feet. The piles were installed using a John Deere 35G Mini-Excavator equipped with an Eskridge 8k Drive Head. Piles were equipped with 40 kip underpinning brackets to allow for connection to the existing footing. Each pile was installed to support an allowable capacity of 20 kips with a factor of safety of two (2). Installation torque was monitored throughout pile installation using a CHANCE Digital Torque Indicator. A calibrated hydraulic jack with PSI gauge was used to set each bracket at the allowable capacity of 20 kips. Once the system was installed benchmarks were set at each pier location so that MGF can easily monitor the structure to verify that no future settlement occurs.