Reinforced concrete
After 17 years of petitioning by residents of Ferndale and the Eel River valley, Humboldt County Supervisors accepted bids for construction in 1910, and work started March 20 of that year. Reinforced concrete was used because studies after the 1906 San Francisco earthquake along of the San Andreas Fault from Ferndale south to San Jose, California showed that reinforced concrete withstood earthquakes. The nearly span cost to build, and consumed millions of board feet of local redwood timber for the framing. Construction was finished and the bridge put into operation on November 8, 1911. As completed, the bridge had wooden trestle approach spans and long. The reinforced concrete structure was long overall with a wide roadway carried on seven long arches. The original wooden approaches were replaced with the current concrete ramps in 1920.