Advocate Argues Immersed Tunnel Alternative Could Save Millions on I-5 Bridge Replacement

Bob Ortblad claims sandwich steel-concrete tube design could cut costs in half compared to current Interstate Bridge Replacement Program plan.

Published on Feb. 5, 2026

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Bob Ortblad, a Seattle-based engineer, argues that an immersed tunnel using sandwich steel-concrete tubes would be a more cost-effective alternative to the current Interstate Bridge Replacement Program (IBR) design. Ortblad claims the IBR's $141 million "bribe" to four upstream marine and metal fabrication firms could be better spent on fabricating seven 400-foot-long sandwich steel-concrete tubes for an immersed tunnel, which he estimates would cost around $181 million total. He accuses the IBR's engineering consultant, WSP, of fraudulently disqualifying the immersed tunnel alternative and exaggerating the costs and risks.

Why it matters

The Interstate Bridge Replacement Program is a major infrastructure project that will have significant impacts on the Portland-Vancouver region. Ortblad's claims, if true, could potentially save hundreds of millions of taxpayer dollars and provide a more cost-effective solution. However, the IBR and WSP have disputed his assertions, so there are competing perspectives on the best approach.

The details

Ortblad argues that an immersed tunnel using sandwich steel-concrete tubes would be a more cost-effective alternative to the current IBR bridge design. He claims the $141 million the IBR plans to pay four upstream firms for bridge clearance mitigation could instead be used to fabricate seven 400-foot-long sandwich steel-concrete tubes that could span 2,800 feet across the Columbia River for around $181 million total. Ortblad accuses WSP, the IBR's engineering consultant, of fraudulently disqualifying the immersed tunnel alternative in a 'Tunnel Concept Assessment' report by making false claims about the construction costs. He says WSP exaggerated the necessary excavation and dredging, and falsely claimed a tunnel would cost twice as much as a bridge.

  • The IBR's 'Tunnel Concept Assessment' report was prepared by WSP engineers on July 14, 2021.
  • The IBR plans to pay $141 million to four upstream firms for bridge clearance mitigation.

The players

Bob Ortblad

A Seattle-based engineer who is advocating for an immersed tunnel alternative to the Interstate Bridge Replacement Program.

WSP

The engineering consulting firm serving as the General Engineering Consultant for the Interstate Bridge Replacement Program. Ortblad accuses WSP of fraudulently disqualifying the immersed tunnel alternative.

Interstate Bridge Replacement Program (IBR)

The major infrastructure project to replace the existing Interstate 5 bridge connecting Portland, Oregon and Vancouver, Washington.

Thompson Metal Fab, Greenberry Industrial, and Vigor Marine

Local marine and metal fabrication firms that Ortblad says could fabricate the sandwich steel-concrete tubes for an immersed tunnel.

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What they’re saying

“Taxpayer money would be better spent on hiring these firms to fabricate seven 400-foot-long sandwich steel-concrete tubes for an immersed tunnel.”

— Bob Ortblad, Engineer (clarkcountytoday.com)

“WSP engineers falsely claimed that the construction of a new casting basin costing hundreds of millions would be needed for the casting of concrete tunnel tubes.”

— Bob Ortblad, Engineer (clarkcountytoday.com)

What’s next

The Interstate Bridge Replacement Program will need to further evaluate Ortblad's claims about the feasibility and cost-effectiveness of an immersed tunnel alternative using sandwich steel-concrete tubes.

The takeaway

This debate highlights the importance of thoroughly evaluating all potential alternatives for major infrastructure projects to ensure taxpayer money is spent wisely. While the IBR has endorsed its current bridge design, Ortblad's proposal could potentially save hundreds of millions if proven viable.