Moffett Creek Bridge, Spanning Moffett Creek at Old Columbia River Highway, Warrendale, Multnomah County, OR

Significance: Moffett Creek Bridge, designed by L.W. Metzger, is considered one of the most unique bridges along the Old Columbia River Highway. The 205 foot structure has an arched span of 170 feet and is 70 feet above Moffett Creek. The bridge is designed to pivot with expansion and contraction caused by the weather on three massive cast iron hinges, one at each abutment and one in the center of the span. At the time of its construction in 1915, it was the largest three-hinged arch in the world. The arch rises only one foot for every ten feet of length. The two arched ribs were designed for a load of 200,000 lbs. distributed uniformly over half the span. The beams and floor span were designed for a twenty ton load. There is a date plaque shield on both sides of the central hinge. There are about 150 precast reinforced concrete posts making up the handrails on each side of the bridge.
Unprocessed Field note material exists for this structure: FN-30
Survey number: HAER OR-49
Building/structure dates: 1915 Initial Construction