Moving Ahead Spring/Summer 2019

Page 20

I-5 Viaduct Retrofit story continued from page 19


Seismic Hazards

Under the study’s recommendation, the viaduct would be widened to the east by 28 feet, thus avoiding properties and Bear Creek to the west. A new vertical support would be built.

The other portion of the study looked at retrofitting the existing viaduct footings by widening and strengthening. The concern is a strong subduction zone earthquake, in which the entire viaduct could simply tip over.

When complete, the viaduct would continue to have 12-foot travel lanes, but emergency shoulders on the right would be 12 feet wide. Inside shoulders would be eight feet wide. Future widening of the interstate through Medford to three lanes could see the viaduct widened, too, by restriping the structure. Travel lanes would be narrowed by 1 foot and allow the emergency shoulder to narrow to 8 feet.

The initial analysis showed the existing soils at the viaduct would require a greater level of design to withstand a greater level of shaking during a seismic event. Additional analysis would be needed for that portion of the project, according to the study. To read the entire project summary and recommendations, go to:

Get Set for Summer Fun! ✓ Hiking ❑

✓ Fishing ❑

✓ Boating ✓ Camping/RV ❑ ❑ Your Summer Driving Headquarters!

Home of the $5K Fishing Derby

1810 W. Main St. Medford • 541-779-5431 MF-00107311


May 17, 2019