Wilson River Bridge, Spans Wilson River at U.S. Highway 101, Tillamook, Tillamook County, OR

Significance: The Wilson River Bridge at Tillamook is the first reinforced-concrete tied-arch span built in the Pacific Northwest region of the United States. In the 1910s, its designer, Conde B. McCullough, worked for the Des Moines, Iowa bridge firm, the Marsh Engineering Company. Its founder James B. Marsh created a patented "rainbow arch" reinforced-concrete bridge, in 1912, which he built all through the states of Kansas and Iowa in the early twentieth century. The success of the Marsh version of the reinforced-concrete tied-arch, using angle steel and concrete, may have influenced C.B. McCullough in his decision to use this form at the Wilson river and shortly thereafter, nearly identical structures over Ten Mile Creek and Big Creek in Lane County, Oregon. McCullough differed from Marsh in that he used reinforcing bar instead of steel plate in his arches. He also created the first reinforced-concrete tied-arch bridges in the Pacific Northwest, the region of the United States that includes western Montana, northern Idaho, Washington and Oregon.
Unprocessed Field note material exists for this structure: FN-23
Survey number: HAER OR-39