Cincinnati Is Replacing the 1932 Western Hills Viaduct With an Extradosed Bridge

The 1932 Western Hills Viaduct carries roughly 55,000 vehicles a day on two decks over the Mill Creek valley, an active CSX rail yard and Interstate 75. Cincinnati is replacing it with a single-deck extradosed structure, a cable-stay and box-girder hybrid, and the design changed after the estimate did.

Project Scope

The 2025 revision cut the main span from eight lanes to six and merged the separate sidewalk and shared-use path into one 14-foot facility, changes the city says save at least $150 million. Deep foundations are the first heavy work, with bridge foundations scheduled for 2027. The existing viaduct stays open to through traffic until the replacement is finished, then comes down. A Walsh Kokosing joint venture, pairing The Walsh Group with Kokosing Construction, holds the construction-manager-at-risk contract for the City of Cincinnati’s Department of Transportation and Engineering, with Hamilton County as a partner. A $127 million federal grant awarded in 2022 anchors the funding, topped up with state grants and a local match.

Why It Matters

The cost line is what other owners will read first. The city’s estimate has gone from $398 million in 2022 to $785.6 million in December 2025, and the value-engineering pass that removed two lanes and simplified the deck is what kept it from going higher. That’s the trade being made on aging urban viaducts across the country right now: capacity gets cut so the structure gets built. The extradosed form is worth noting too. It’s common in Japan and increasingly in Europe, less so on American city arterials, and choosing it over a conventional girder crossing reflects how tight the geometry is over an operating rail yard.

Project Team & Details