Drilled Shafts Portland Aerial Tram / Portland, OR Included the installation of 193-24″ diameter drilled shafts to depths of 85′ in silts, sands and basalt. TBH utilized slurry to stabilize shaft sidewalls. Columbia Center Blvd Meacham Bridge Related Case Studies UPRR Prebore ShaftsBlock 35 John RossI-205 Columbia & Willamette River…I-84 at the DallesNE Hwy 99 – NE…WB Passing Lane – US…Bear Creek BridgeInfluent Pump StationTacoma Second Supply PipelineCalpine-McNary Transmission Line