Chicago River Bascule Bridges, Spanning Chicago River & its north & south branches, Chicago, Cook County, IL

Significance: The development of the Chicago trunnion bascule bridge occurred during the first three decades of the twentieth century. Despite the controversy over patent infringement Joseph E. Strauss charged the City of Chicago engineers with infringing on his patented Strauss-Trunion bascule bridge the Chicago bascule received great acclaim within the civil engineering profession. // Between 1865 and 1890, the City of Chicago built 55 movable highway bridges over waterways within municipal limits. All were center-pier swing spans. Despite its ubiquity, the swing span was not universally admired. Its critics pointed to the fact that the center-pier design was becoming a navigational hazard for the ever-larger vessels of the late nineteenth century.
Unprocessed Field note material exists for this structure: N642
Survey number: HAER IL-111
Building/structure dates: 1900 Initial Construction