Sellwood Bridge Replacement and Landslide Stabilization, Portland, Oregon
In 2016, Multnomah County replaced the Sellwood Bridge, one of the major bridges in the Portland Metro Area, within the existing footprint. The original bridge, constructed in 1925, was impacted by a large, ancient landslide causing significant structural distress to the west abutment and bridge superstructure. 
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CCI-LT was retained as part of a multi-discipline bridge design team to evaluate the landslide and develop stabilization measures that were compatible with a new arch bridge. ​The Sellwood Bridge is a vital link between Portland's east and west sides. It's one of the busiest two-lane bridges in Oregon, carrying an average of 30,000 vehicles daily.
Project Highlights
The western approach to the Sellwood Bridge site is a complex network of existing and temporary foundations along with new foundations for bridge and viaducts, sandwiched into a very tight space on the hillside between Highway 43 and the Willamette River. CCILT developed an anchored shear pile system that arrested the landslide movement.
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​The stabilization system consists of forty, six-foot-diameter drilled shafts and seventy high-capacity ground anchors with loads of up to 850 kips each. The drilled shafts are connected by a near-surface grade beam which allows the ground anchor loads to be distributed among several shafts. The design effort required intensive 3D modeling to ensure that the ground anchors were threaded safely through a virtual forest of foundation piles and underground utilities. The landslide stabilization system was designed to be completely hidden from view.
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3D model showcasing the ground anchors and future travel corridors. The project included extensive modeling to ensure that anchors were threaded through buried foundations and utilities.
Owner: Multnomah County Bridge Division
More Information: KATU - Sellwood Bridge Open for Pedestrians and Drivers