Interstate Bridge Replacement (I-5 Columbia River)

The biggest bridge job on the West Coast is moving toward a contractor. The Interstate Bridge Replacement Program will rebuild the aging I-5 crossing of the Columbia River between Portland, Oregon, and Vancouver, Washington, replacing a pair of century-old spans that bottleneck one of the region’s most critical freight and commuter corridors. The program’s latest estimate puts the full cost between $13.5 billion and $15.2 billion.

Project Scope

The replacement covers new bridges plus the connecting interchanges and transit improvements along the I-5 corridor. Oregon and Washington are delivering it jointly through progressive design-build, with the bridge contractor procurement advertising in 2026, design and price negotiation in 2027, and major construction starting in 2028. The core bridge contract alone is estimated at $1 billion to $1.5 billion over four to six years. With roughly $5.5 billion in committed funding, the program is advancing the core projects while the remaining money is secured.

Why It Matters

The I-5 bridges are a single point of failure for travel between two states, and they’re seismically vulnerable, a real risk in a region overdue for a major Cascadia earthquake. Replacing them removes a chokepoint that costs the regional economy daily in freight delay and congestion. The cost trajectory is its own story: the estimate has climbed roughly 140% from a 2022 figure of $6 billion, driven by schedule slips and a 58% escalation in materials and labor. It’s a stark illustration of how much megaproject economics have shifted this decade, and why owners are turning to collaborative delivery to manage the risk.

Project Team & Details