A. H. Beck provided design/build services for construction of four vertical tunnel access shafts at 28 feet in diameter with depths up to 60 feet for the City of Austin’s new wastewater tunnel expansion project along the Colorado River. Secant pile compression ring shoring was installed along the peripheral of each shaft to ensure a watertight finished cell into the underlying bedrock. A. H. Beck utilized a hydraulic casing oscillator manufactured by Leffer to advance and retrieve segmental double wall temporary steel casing through the water bearing soils.
The high water table presence and soft unstable alluvial soils present at the work site dictated the use of full-length segmental temporary casing. High slump delayed set concrete was used to ensure concrete workability throughout the placement operations and successful full length casing retrieval.
GENERAL CONTRACTOR: SAK/Quest, JV