Text Size:   A+ A- A   •   Text Only
Site Image

SW Iowa Street Viaduct Replacement Project

Project Summary:
This project replaces the I-5 viaduct structures crossing over a ravine that leads to Iowa Street in Southwest Portland. Construction began in the summer of 2010 and will continue through 2014. Click here for a project summary. 
Latest Informion
Construction Update October 2013 
A new barrier was installed on the northbound right shoulder in early October. The next steps will be to remove the detour bridge, west of the freeway; complete the embankment in front of the west side retaining walls; build the pedestrian trail under the bridge and complete final landscaping.
The Iowa Street project replaces deteriorating 55-year-old viaducts at milepost 298, just north of the Terwilliger Curves. The new viaducts will meet today’s roadway and seismic standards with wider shoulders, wider center medians and new retaining walls.

The speed limit on I-5 remains 50 mph in the work area. This speed reduction is in effect 24 hours a day and will be in place for the duration of the project. Please be alert to enhanced police traffic patrols in the work area. Throughout construction three lanes will remain open in each direction during weekday, daytime hours. 


On August 27th, traffic was rerouted to the new southbound Iowa Street viaduct on Interstate 5.   See photos below.

In mid-December 2012, all northbound traffic was shifted onto the completed new northbound viaduct.  During this spring of 2013, the old southbound viaduct was demolished and work began on the new southbound viaduct. Click here to view the current project schedule in a graphic (pdf) format. 

Check back for project updates and construction milestones.

Weekly Construction Updates
Click here to see the weekly construction update and traffic impacts on this project.

Click here for a project newsletter. You'll find information and pictures of tree plantings, bridge demolition and more.


Throughout construction of the viaduct, ODOT would like to meet periodically with interested community members at a series of informal get-togethers. Look here for information about future meetings with the construction team. If you or your group would like a project information briefing, please contact Susan Hanson, Community Affairs Coordinator at 503-731-3490 or susan.c.hanson@odot.state.or.us


Project Information
Work on the Oregon Department of Transportation's project to replace the twin Interstate 5 viaducts, crossing a ravine that leads to SW Iowa Street, started in August 2010.  Wildish Standard Paving Company of Eugene, Oregon, is the prime contractor on the project.
The Interstate 5: Iowa St. Viaduct Replacement project is located at milepost 298, just north of the Terwilliger Curves. The viaduct – technically two viaducts side-by-side – was completed in 1957, with three lanes in each direction and substandard three-foot shoulders. The new viaduct will include standard shoulder widths, a wider median and maintain three lanes in each direction.
Click here for a project summary (December 2012) with the latest project information, bridge demolition, traffic shifts and more.
Project Benefits

** The existing decks of the I-5 Iowa viaducts are in poor condition and the viaducts do not meet the current “life line” seismic standards. ODOT’s bridge maintenance unit had done several patching projects on the deck. These patches were failing while new cracks continued to appear. The new viaducts will meet current roadway and seismic standards.
**The replacement viaducts will maintain three travel lanes in each direction. Safety will be improved with wider shoulders, wider center medians and higher concrete barrier. The new viaducts will be wide enough to accommodate a future truck-climbing lane for southbound I-5 traffic.
**The trail passing under the viaducts will be rebuilt to City of Portland trail standards. Maintenance of the trail will be handed over to the City following project completion.  Click here to see the trail detour map.
I-5 Traffic Impacts
In order to accommodate traffic mobility during construction, a temporary three-lane detour structure was built to the west of the existing viaducts. During construction, motorists should expect lane closures on northbound and southbound I-5 during nighttime hours and on some weekend days. Also, the contractor may need to temporarily close lanes on Barbur Boulevard for access in and out of the western side of the project area.
Noise Impacts
Much of the project work is expected to take place during daytime hours.  For example, pile driving will only take place during the day.  However, work that requires lane closures on I-5 will take place during nightime and weekend hours.  ODOT has received permission (a noise variance) from the City of Portland for nighttime and weekend work during construction.
To report noise problems or construction incidents requiring immediate attention, 24 hours a day, call 503 412-2356.


View looking southbound                                             View looking northbound

On August 27 2013, traffic was rerouted to the new southbound Iowa Street viaduct on Interstate 5. These photos show the shift to the permanent lanes from the temporary lanes. 

Project Schedule
Wildish Standard Paving Co. of Eugene, Oregon started work on this four-year bridge replacement project in summer 2010. Following is a projected schedule of work, subject to change due to contractor activity, unforeseen delays and weather conditions:
Summer 2010 - Summer 2011
During this period the contractor excavated and constructed the west side retaining walls and built the temporary detour bridge and roadway.
Summer 2011 - Fall 2012
During this period the contractor shifted northbound traffic to the southbound bridge. I-5 southbound traffic shifted to the temporary roadway on the west side. The existing I-5 northbound bridge was demolished. Work was completed on the new northbound bridge supports.  The contractor completed the east side retaining walls and finished the new I-5 northbound bridge. Once the northbound bridge barrier is finished, northbound I-5 traffic will be shifted to the new northbound bridge. Also, trees were planted on the west side in areas not impacted by construction.
Fall 2012 – Summer 2013
The contractor will demolish the existing I-5 southbound bridge, construct the new I-5 southbound bridge and shift I-5 southbound traffic from the west side detour bridge to the new permanent southbound bridge.
Fall 2013 – Summer 2014
During this period work will be done to remove the detour bridge (the western most lanes), install the Oregon Basalt fascia, complete the embankment in front of the west side retaining walls, build the pedestrian trail under the bridge and complete final landscaping. 
Click here to view the current project schedule in a graphic (pdf) format. 
**To be added to a weekly construction update list, please contact Susan Hanson via e-mail or phone (see below for contact details.
Retaining Wall Facade
Retaining Walls 
You’ve probably seen the retaining wall construction taking place to the west of I-5 in the Iowa Street Viaduct replacement area. These retaining walls will reinforce the existing slopes in the project area (there also will be smaller retaining walls built to the east of I-5 when work shifts to that side).

What you see out there is not the finished product. The contractor ultimately will install a concrete wall treatment (or façade). To minimize the sight of the westside wall, which is more than 40 feet high in parts, a slope planted with trees and shrubs will be installed in the final stages of the project. Trees and shrubs also will be planted alongside the eastside walls at the end of construction.

From May 15, 2011, to June 15, 2011, ODOT solicited feedback from the community and other stakeholders on the wall types. We received more than 400 responses. The most popular choice for the wall treatment is Oregon Basalt. ODOT, therefore, will go ahead with installing Oregon Basalt wall treatment on all walls facing motorists or residents. Thanks to everyone who participated in the online survey or who sent comments or let us know what they thought at several public events we attended.
OREGON BASALTClick here for a print-sized version (pdf format) of the Oregon Basalt wall treatment.
ODOT Contact Information
Community Affairs Coordinator
Susan Hanson
December 2012 newsletter.pdfDecember 2012 newsletter.pdf