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Cortland Street Bridge

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Photos 

View Of Eastern Bridge Portal, Looking West

Photo taken by Historic American Engineering Record

View photos at Library of Congress

Map 

Description 

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.

Facts 

Overview
Double-leaf bascule bridge over North Branch Chicago River on W. Cortland Street in Chicago
Location
Chicago, Cook County, Illinois
Status
Open to traffic
History
Built 1901-02
Builders
- American Bridge Co. of New York
- Fitzsimons & Connell Co.
- John Ericson
Design
Bascule Pratt through truss
Dimensions
Length of largest span: 127.9 ft.
Total length: 216.8 ft.
Deck width: 36.0 ft.
Vertical clearance above deck: 16.1 ft.
Recognition
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)
13,200

Update Log 

  • May 17, 2010: Updated by J.R. Manning: Added description from HAER Report
  • July 25, 2008: New photos from James Baughn

Sources