North Avenue Bridge, Spanning North Branch of Chicago River at West Nor, Chicago, Cook County, IL
Photo Caption Pages
Spanning North Branch of Chicago River at West Nor, Chicago, IL
Find maps of Chicago, IL
Documentation compiled after 1968.
Survey number HAER IL-154
Building/structure dates: 1907 demolished
Significance: When Chicago became a major commercial and industrial center after the Civil War, the most common American drawbridge was the swing bridge, horizontally rotating on a center pier to open two navigation channels. The center pier, however, became a navigational hazard for the ever-larger craft of the late nineteenth century, especially on crowded, narrow waterways such as the Chicago River. During the late 1890s, Chicago City Engineer John Ericson initiated a planning study to find an alternative to the swing span. Finding inspiration in the 1894 Tower Bridge in London, England, the municipal engineering staff developed a new movable-bridge design. The type was known as a double-leaf bascule, French for "seesaw." Each movable leaf rotated vertically on a fixed, horizontal steel axle, or trunnion, leaving the entire river channel open for shipping. With the front of each leaf counterbalanced by weights at the rear, relatively small motors could open and close the bridge. The city built its first fixed-trunnion bascule in 1902. The North Avenue Bridge, completed in 1907, was the seventh of the new type to go into operation.
American Bridge Company, Toledo
Von Babo , Alexander
Pihlfeldt, Thomas G.
Jackson & Corbett Company
Roemheld & Gallery Company
Chicago Department Of Transportation
Hess, Jeffrey A., Historian
Lowe, Jet, Photographer
Historic American Engineering Record (Library of Congress)
1. AERIAL VIEW FROM THE SW OF NORTH AVENUE BRIDGE TO THE RIGHT. CHICAGO, MILWAUKEE AND ST PAUL 'Z-2' RAILROAD BRIDGE ON RIGHT.
2. VIEW OF LIFT ENGINE FRAME WORK ABSENT ELECTRIC MOTOR.
3. BRAKE AND GEARS FACING OUT TOWARD WATER.
4. BRAKE AND GEARS DETAIL AT CORNER OF PIT.
5. NORTH LEAF MIDDLE TRUNNION WITH TRUNNION SUPPORT TRUSS AND COUNTERWEIGHT (TO THE REAR) LOOKING NORTHWEST.
6. NORTH AVENUE BRIDGE LOOKING SOUTH IN ELEVATION.
7. ELEVATION FROM ROOFTOP, EASTERN PORTAL PERSPECTIVE.
8. ELEVATION FROM ACROSS THE RIVER.
9. WESTERN PORTAL.
10. DETAIL OF INTERIOR OF STRUCTURE AT WEST PORTAL, VIEW FACING NORTH.
11. STREET LEVEL PORTAL ELEVATION.
12. STRUCTURAL DETAIL OF WESTERN PORTAL.
13. STRUCTURAL DETAIL OF CENTRAL TRUSS OF WESTERN PORTAL.
Back to Chicago, Illinois