Using Thermal Integrity Profiling (TIP) to Monitor Shaft Cooling System for Large Diameter Drilled Shafts

Large diameter drilled shafts can meet the criteria for mass concrete, and the South Carolina Department of Transportation (SCDOT) is considering provisions to limit the maximum overall and the maximum temperature differential across these shafts. To meet project specific requirements, a design-build team developed a cooling system consisting of six steel access tubes installed in an approximately 0.4 m (2 ft) diameter circle around the center of nineteen 2.5 m (8 ft 2 in.) diameter drilled shafts. PVC tremie pipe was inserted inside the steel tubes to the bottom of the shafts to convey water from the bottom of the tubes back up to the top of shaft after concreting was complete. Thermal (TIP) wires were installed in these shafts to measure temperatures on 1-ft vertical increments at multiple locations around the perimeter and in the interior of each shaft. The variations in temperature within the shafts due to the cooling system are discussed, and conclusions about the effectiveness of the cooling system to meet project requirements are also presented.