Partial Viaduct, Milepoint 40.3 on North Santiam Highway (Route 22), Detroit, Marion, OR

Significance: The Partial Viaduct #7964 is a seventeen span reinforced concrete viaduct comprised of span lengths from 21'-5" to 25'-0". The overall length of the structure is 417' and it is supported by square concrete piers at each bent. A stonemasonry guardwall runs the length of the deck, on both sides. The stone is uncoursed and bonded with mortar. The crenellated walls are approximately 30" in height, and the cenellations are approximately 36" high and appear at regular intervals consistent with the longitudinal beam spacing (below deck). The viaduct exhibits the design hallmarks of the Cascadian and Rustic architectural styles that were utilized extensively in the Cascades region during the 1920's and 1930's. The structure was completed shortly before construction of 2 dams in the area: the Detroit Dam and Big Cliff Dam. Construction of these dams created a reservoir which subsequently submerged portions of the original highway alignment at this location.
Survey number: HAER OR-142
Building/structure dates: 1947 Initial Construction