P. Mervyn Stephenson

View Exhibit map

P. Mervyn Stephenson was the Oregon State Bridge Engineer from 1955 to 1957. During Stephensonís time as bridge engineer, many of the initial steps were taken for the creation of the interstate highway system in the state of Oregon. Most of the bridges constructed during his two year tenure were located on what is now Interstate 5, such as the I-5 Winchester Bridge, and the since replaced I-5 Fords Bridge.

The single most important project Stephenson and his staff under took was the design and construction of the expansion of the Interstate Bridge between Portland, Oregon and Vancouver, Washington. This project included designing a new southbound bridge over the Columbia River and practically rebuilding a large portion of the existing northbound structure, which was constructed in 1917.

Stephenson began his engineering career in 1919 as construction engineer under the direction of his former college professor and newly appointed state bridge engineer Conde B. McCullough. During his time with the Oregon State Highway Department Stephenson witnessed bridge construction evolve from the heavily ornate arch bridges of the 1920ís and 30ís to the mass production construction techniques of the interstate age.

Engineering History

- Various Engineer, Oregon State Highway Department (1919-1955)

- State Bridge Engineer, Oregon State Highway Department, (1955-1957)


Carver Bridge (Clackamas County, Oregon)
1955 - Bridge Engineer, 1930
Parker through truss bridge over Clackamas River on South Springwater Road
Replaced by a new bridge in 2013

I-5 - Fords Bridge (Douglas County, Oregon)
Bridge Engineer, 1957
Lost Warren deck truss bridge over South Umpqua River on I-5
Replaced by new bridge

I-5 - Interstate Bridge (Southbound) (Multnomah County, Oregon)
Bridge Engineer, 1958
Vertical lift Parker through truss bridge over Columbia River on Southbound I-5
Open to traffic

I-5 - Santiam River Bridge (Marion County, Oregon)
1958 - Bridge Engineer, 1946
Lost pair of steel arch bridges over Santiam River on Interstate 5
Replaced by new bridge

I-5 - Winchester Bridge (Northbound) (Douglas County, Oregon)
Bridge Engineer, 1955
Warren deck truss bridge over North Umpqua River on I-5 in Roseburg
Open to traffic

Isthmus Slough Bridge (Coos County, Oregon)
Bridge Engineer, 1955
Through truss bridge over Isthmus Slough on FAS A-396
Replaced by a Concrete Box Girder Bridge in 2004

UP - Hinkle Undercrossing (Umatilla County, Oregon)
Bridge Engineer, 1956
Steel stringer bridge over OR-207 on Union Pacific Railroad
Open to traffic