In 2018-19, DA Smith* conventionally cored 22-inch-diameter holes producing 18-inch-diameter concrete cores to depths of 35 feet on the crest of Shasta Dam for the US Bureau of Reclamation (USBR). Large-diameter cores were required for concrete properties testing as part of the Shasta Dam Raise Project. ASTM standards required the core diameter to be a multiple of the diameter of the largest coarse aggregate in the concrete.
DA Smith worked with Groupe Fordia Inc. and Northwest Machine to design and build a custom 22-inch-diameter conventional coring system for the project.
Each 5-foot core run, weighing approximately 1,000 pounds, was boxed in specially designed crates and shipped via temperature-controlled freight to the Denver Federal Center for material properties testing. The 22-inch holes and other 10-inch, 80-foot-deep holes were tremie-grouted with non-shrink concrete.
The USBR successfully tested the compressive strength of the concrete cores using its 5-million pound Universal Testing Machine at the USBR Technical Service Center in Denver, Colorado.
* Formerly as Agapito Associates, Inc.