With larger buildings come deeper and larger foundations. Drilled caissons or “piers” are one of the most commonly used foundation types for the most heavily loaded buildings as well as most bridges and overpasses. In order to be confident that each pier will support a building as designed, in-depth inspections must be performed. These inspections include verification of the final bearing materials as well as rock quality throughout the designed rock socket and verification that the bottom of the pier is cleaned out prior to concrete placement.
Historically, the only way to inspect final bearing materials and rock quality was to send an inspector into the pier. Providing that sort of access, however, comes with considerable logistical and safety issues. And, down-hole inspections are not helpful in determining the integrity of the concrete shaft after it’s in place.
Today there are more options for drill pier inspections that keep personnel out of the hole and can help evaluate the integrity of the concrete for the completed drilled pier. First, a high resolution specialty camera, also known as a shaft inspection device, is used by the inspector to check the integrity of the rock at the base and along the walls of the excavation to verify the bearing surface has been cleaned appropriately. Once this is done, and the concrete is placed, Cross-Hole Sonic Logging (CSL) can be used to check for discontinuities within the placed concrete.
Using SID camera and CSL methods are safer for the employee, generate more accurate and detailed results, and is more cost effective for the client because it reduces the amount of time each drill rig is setup on each hole to allow for down-hole access. SCI frequently uses these methods and have done so on recent projects including the new RGA buildings in Chesterfield, the new towers at BJC currently under construction, the Creve Coeur Assisted Living facility, and a replacement railroad bridge at Fort Leonard Wood to name a few. Let us know how we can help you with your next project.
