The study will assist ODOT, the Federal Highway Administration, the City of Medford, the Rogue Valley Metropolitan Planning Organization, and Jackson County in understanding conceptual costs and potential impacts of a one-sided seismic retrofit and widening of the existing I-5 Medford Viaduct structure. The project team intends to widen the viaduct by 28 feet to either the east side or west side of the structure.  

Shannon & Wilson provided geotechnical engineering services for this project. Our services included a site reconnaissance, seismic hazard evaluation, and recommendations for the retrofit and widening of the viaduct. Because this project involved multiple review agencies, we had to be proactive in working with the project team to adhere to all federal, state, and local standards to keep the schedule and budget on track. A week before drilling was supposed to start, the ODOT Environmental team notified us that the city park falls under the Section 4(f) FHWA jurisdiction. This would have required a separate permit for drilling that we would not be able to secure by the time drilling needed to start; in addition, it would have caused a budget change for the additional coordination. We quickly worked with ODOT, the City, and our prime to move the boring location out of the park and onto the existing trail under the viaduct, a location that would also provide us with valuable subsurface information. Based on observations during our site reconnaissance, Shannon & Wilson found widening the viaduct to the west may be difficult due to Bear Creek and the steep creek bank, which runs along the west side of the viaduct for most of its length.