Neawanna Creek Bridge, Spanning Neawanna Creek at Milepoint 19.72 on U.S. 101 (Oregon Coast Highway), Seaside, Clatsop County, OR

Significance: The Neawanna Creek Bridge #1305 is significant as an intact example of a 1930s continuous concrete, multi-span highway bridge, utilizing Hardy Cross's moment distribution theory, and for its association with C.B. McCullough, Oregon's premier bridge engineer. The configuration of continuous concrete T-Beam construction utilized in the design of the 1930 Neawanna Creek Bridge represents a significant change in structural engineering theory and reinforced concrete technology by applying the moment distribution technique of distributing loads on girder structures. The moment distribution theory for continuous concrete frames was developed in the late 1920s by Hardy Cross, a civil engineer and professor of structural engineering at the University of Illinois. Hardy Cross was regarded by his contemporaries as a leader in a new school of thought in the field of structural analysis, and his theory is regarded by many architects and engineers to be one of the more significant structural theories developed during the 20th century. C.B. McCullough served as State Bridge Engineer, and later as the Assistant State Highway Engineer, of Oregon from 1919 until his death in 1946. He authored a number of books and technical articles on bridge design and construction. McCullough is significant for his use of innovative bridge technology, and for his visually appealing designs. He had attained international recognition for the large-scale structures designed to span the major rivers and estuaries along the Oregon coast for the completion of the Orange Coast Highway in the 1930s.
Survey number: HAER OR-129