A busy summer of highway construction, building new ramps, roadways and retaining walls, should result in people driving on much of the new Fern Valley Interchange by next spring.
The $72 million project addresses traffic congestion in and around Interstate 5 Exit 24, the Phoenix interchange, especially severe during morning and evening commutes.
Existing and proposed development along the east side of I-5 in Phoenix had reduced the capacity and created safety issues at the interchange. The project area includes I-5, Oregon 99 and Fern Valley Road. The project is scheduled for completion in September 2016.
“The new interstate bridge will be open as well the north side ramps by next spring,” said Assistant Project Manager Eric Finney. “Traffic coming from or to Medford from Phoenix will be on the permanent ramps instead of temporary ones.”
However, temporary ramps will still be in place on the south side of the new interchange, including the existing temporary southbound on-ramp and a new northbound off-ramp using either Pear Tree Lane or South Phoenix Road.
“Once we get new traffic on the bridge, the existing two-lane span will be demolished,” said Finney.
Demolition is crucial for prime contractor Hamilton Construction of Springfield as it begins building the new northbound off-ramp and tying it into the new structure.
Luman Road intersection
There is a large difference in elevation between the newly finished concrete roadway being constructed east of the Fern Valley-Luman Road intersection and where traffic is currently moving.
“The challenge will be to bridge the difference and still keep traffic moving and businesses accessible,” said Finney.
Hamilton is presenting ODOT with a plan to gradually raise the elevation over the course of several nights of work, perhaps over a week, gradually raising the grade with rock before it’s paved.
The interchange area will be constructed using concrete as the permanent roadway surface, which will last decades longer than asphalt, especially in the areas where there is a lot of stop-and-go traffic with heavy trucks.
Paving and curb work is underway west of the Bear Creek Bridge on the south side of Fern Valley Road, near the recently developed commercial triangle. Traffic is running on the recently completed north section.
Once Fern Valley Road is complete, Hamilton is expected to move to the east side of Oregon 99 and then onto Bolz Road.
“The west side of Oregon 99 may not take place until next summer when the project is in the final stretch and final paving is scheduled,” said Finney.
Business driveways will be marked with cones and blue ‘Business Access’ signs. When complete, Oregon 99 will feature new turn lanes, bike lanes, sidewalks and traffic signals.
“This work will be the most challenging construction phase for the city of Phoenix and local businesses,” said Finney. “The work is right in the core of Phoenix, alongside businesses and the Oregon 99 corridor.”
Diverging Diamond interchange
The Fern Valley Interchange features Oregon’s first Diverging Diamond design that reduces ODOT’s right of way needs for construction.
“The Diverging Diamond design provides more traffic capacity,” said Public Information Officer Gary Leaming. “To enter I-5 or cross over it, drivers will move to the opposite side of the bridge, which reduces the number of signal phases a driver needs to clear.”
The Missouri Department of Transportation was the first public agency in the United States to construct an interchange with the crossing diamond design.
With the partial opening of the interchange, traffic will begin to experience the DDI design.
The Fern Valley Interchange project’s size and complexity, encompassing I-5, Oregon 99 and Fern Valley Road, requires more than two full construction seasons to complete.
Aesthetic features inspired by the hills and grasses — the natural colors surrounding Phoenix — are being incorporated in the final design for the new Fern Valley Interchange project.
The utilization of concrete form liners and different stains and paints presents opportunities to design a bridge with a local look instead of the drab concrete structures common when I-5 was initially built.
The project team filtered through several designs with the help of Medford landscape architect, John Galbraith, before selecting aesthetics for the Fern Valley Road bridges that span I-5 and Bear Creek at Exit 24.