Accelerated Bridge Construction
University Transportation Center

ABC Project and Research Databases

1973 – Fremont Bridge

Year ABC Built: 1973
State: OR
Owner: State
Location: Urban
Spans: Three-span
Beam material: Steel
Max Span Length (ft.): 1255
Total Bridge Length (ft.): 2152
Construction Equipment Category: Other ABC Method
ABC Construction Equipment: Strand jacks; Float in
State ID Number: 2529
NBI Number: 2529
45.5342789 | Longitude: -100

Under Construction

Bridge Description

Project Summary:

Project Location:

I-405 / US 30 over the Willamette River in the city of Portland in Multnomah County

Impact Category:

Tier 6 (longer but reduced by months/years)

Mobility Impact Time:

Primary Drivers:

reduced onsite construction time; improved site constructability; minimized environmental impacts; reduced traffic impacts – least impact on navigational traffic; reduced life-cycle cost – least cost to build; improved work-zone safety – reduced worker exposure over waterway


2,152-ft-long, three-span continuous, semi-through steel tied arch main structure (451.83 ft side deck arch span – 1,255 ft drop-in tied arch center span (ABC) – 451.83 ft side deck arch span); 6,000-ton drop-in tied arch raised 175 ft into place

Average Daily Traffic (at time of construction):


Traffic Management (if constructed conventionally):

Existing Bridge Description:

Replacement or New Bridge:

The bridge has an upper and lower deck, each carrying four 12-ft-wide traffic lanes and two 10-ft-wide shoulders. The cross-section consists of a steel tied arch welded box girder supporting an orthotropic steel upper deck and a concrete lower deck system. The concrete piers were on concrete footings founded on deep foundations.

Construction Method:

The arch span was built in California and floated 1.7 miles downstream of the bridge site at Swan Island, where it was assembled. It was then floated on barges to the bridge site and lifted into position using strand jacks. This construction method was selected to minimize cost and the impact on navigation.

Stakeholder Feedback:

This is a proven and common construction method for prefabricated long-span bridges over navigable waterways. Floating a fully erected span accelerates the construction schedule and reduces the workers’ exposure over the waterway, thus increases workers’ safety. It also reduces the window time of the river closure and impact to shipping traffic.

High Performance Material:

Project Planning

Decision Making Tools: State Process
Site Procurement:
Project Delivery: Design-bid-build
Contracting: Full lane closure

Geotechnical Solutions

Foundations & Walls:
Rapid Embankment:

Structural Solutions

Prefabricated Bridge Elements: Orthotropic deck
Prefabricated Bridge Systems:
Miscellaneous Prefabricated: Arch span w/deck

Costs & Funding


Insufficient records to reconstruct exact cost information. Published record listed $82 million as the total cost, but the main structure alone is about half that amount. In 1973, the bridge cost per sq ft was under $140.

Funding Source:

Federal and State

Incentive Program:

Additional Information

Downloadable Resources

Contract Plans:


Bid Tabs:

Construction Schedule:

Other Related Information:

Summary Sheet:

Other Related URLs:

Go to:

Photo Credits:

Oregon Department of Transportation


Bruce V. Johnson, P.E.
State Bridge Engineer
Oregon Department of Transportation