I-5 project may need costly redesign

PORTLAND – A newspaper investigation has turned up new questions about the proposed design of an Interstate 5 replacement bridge across the Columbia River.

Documents show the project’s sponsors either didn’t know about or didn’t accommodate concerns about the bridge’s height, the Oregonian newspaper reported Friday.

For instance, the Oregonian reported, after seven years of work the planners didn’t know until February that the 95-foot clearance would be too low for a U.S. Army Corps of Engineers dredge that’s 116 feet high.

And the proposed bridge isn’t high enough for a growing number of companies along the river that employ a total of 600 people making big equipment such as oil-drilling rigs that get sent downriver a few times a year.

The bridge is expected to cost $3 billion and accommodate vehicle traffic, light-rail mass transit, bicyclists and pedestrians. The sponsors say it would help commuter and freight traffic and be less vulnerable to earthquakes. The current bridge is two spans, one dating to 1917, the other to 1958.

Planners have already spent $140 million and redesigned the proposed bridge when outside analysts faulted a plan as risky and untested. Another redesign might add $100 million in costs.

The current bridge has a lift section that can provide clearance of 178 feet. Project sponsors said a 95-foot clearance on a new bridge would accommodate all but a few river users.

But, the Oregonian report shows, the project’s planners overlooked the dredge and didn’t notice that more steel fabrication companies were joining the likes of Thompson Metal Fab, which operates in a former Kaiser shipyard on the north bank of the Columbia in Vancouver, Wash.

Project officials are proposing compromises to salvage the current design, such as persuading the fabricators to leave their hulking products partially assembled until they clear the bridge and then to finish assembly downriver.