Project Background

The existing North Dakota Street Bridge over Fanno Creek has reached the end of its useful

Existing Bridge

lifespan. A replacement bridge designed to modern seismic and structural design codes is needed to maintain the safety of drivers, pedestrians, and bicyclists using the bridge well into the future.

To confirm safety, the City of Tigard inspects in-service bridges every two years. During a routine inspection in 2015, the deteriorated condition was identified, requiring the closure of the bridge. An immediate, but temporary, repair to the substructure was designed and constructed to safely reopen the bridge. In addition to substructure repairs, the existing bridge is only 21 feet wide and lacked a safe crossing for pedestrians. As part of the short-term repair, the City added a temporary sidewalk to improve safety for pedestrians. This design and repair were completed in less than six weeks to quickly restore traffic. However, the repair was only designed to last for five years.

Above and below: existing bridge substructure repairs to reinforce decayed timbers

With the bridge temporarily restored to safe conditions, the City applied for and received Oregon Department of Transportation (ODOT) Local Agency Bridge Program funding to replace the bridge. In addition to providing a safe structure with a 75-year design life, the bridge will also be designed to minimize flooding over the roadway, further improve bicycle and pedestrian connections, and meet current seismic design standards.

The project is one of several planned bridge replacement projects in the area, including the replacement of the Tigard Street Bridge over Fanno Creek and the Hall Boulevard Bridge over Highway 217. Construction of these projects will be coordinated to minimize the overall disruption to traffic in the area.