Cortland Street Bridge
Designated a landmark by the American Society of Civil Engineers, the Cortland Street Bridge is a double-leaf bascule span that became in the early twentieth century the standard for movable bridges designed by the city engineer of Chicago. The Cortland Street bridge was the first of this type and featured electric motors that drove pinion gears which engaged a rack attached to the end of each truss. Counterweights on the shore sides of the bridge counterbalanced the roadway and superstructure that spanned the river and thus little power was required to raise or lower the bridge. When raised, each leaf assumed a nearly vertical position providing a wide clearance for vessels plying the river. City engineers designed the machinery so that the bridge could open within one minute during calm weather and under three minutes during windy conditions.
From a report prepared for the American Historic Engineering Record, 1987. HAER photos by Jet Lowe.
- Double-leaf bascule bridge over North Branch Chicago River on W. Cortland Street in Chicago
- Chicago, Cook County, Illinois
- Open to traffic
- Built 1901-02
- - American Bridge Co. of New York
- Fitzsimons & Connell Co.
- John Ericson
- Bascule Pratt through truss
Length of largest span: 127.9 ft.
Total length: 216.8 ft.
Deck width: 36.0 ft.
Vertical clearance above deck: 16.1 ft.
Eligible for the National Register of Historic Places
- Approximate latitude, longitude
- +41.91694, -87.66361 (decimal degrees)
41°55'01" N, 87°39'49" W (degrees°minutes'seconds")
- Approximate UTM coordinates
- 16/444969/4640767 (zone/easting/northing)
- USGS topographic map
- Chicago Loop
- Inventory numbers
- IL 016-6011 (Illinois bridge number)
BH 15116 (Bridgehunter.com ID)
- Inspection (as of 09/2011)
- Deck condition rating: Good (7 out of 9)
Superstructure condition rating: Poor (4 out of 9)
Substructure condition rating: Fair (5 out of 9)
Appraisal: Structurally deficient
Sufficiency rating: 37.9 (out of 100)
- Average daily traffic (as of 2010)
- May 17, 2010: Updated by J.R. Manning: Added description from HAER Report
- July 25, 2008: New photos from James Baughn