The Oyster River Upstream Bridge carries the four-lane Vancouver Island Highway over the Oyster River Canyon, between Courtenay and Campbell River, and has three spans of 26, 39.5 and 26 metres. The sides of the canyon have been undercut by scour action at the bridge site. The piers were inclined to limit the length of the girders and to locate their pier footings away from the undercut zones. To resist the high 0.47g earthquake ground accelerations predicted for the site, the superstructure is built in at the two twin column bents, with the columns designed to plastic hinge. At the abutments, the girders are supported on elastomeric base isolation bearings. To minimize dynamic seismic soil forces, the two abutments are buried spill-through type structures each with two buried column type supports. The abutment columns are pinned down at the bottom to accommodate earthquake displacements, with anchored settlement slabs propping the abutments. Girder designs with both standard pre-stressed concrete and welded steel sections were carried out and tendered. The concrete alternative was constructed.

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