North Avenue Bridge

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North Avenue Bridge
Official name	North Avenue Bridge
Carries	4 lanes of North Avenue (ILL 64), 2 bicycle lanes, 2 sidewalks
Crosses	Chicago River
Locale	Chicago
Design	Hybrid suspension/cable-stayed
Height	45 ft [1]
Vertical clearance	18 ft
AADT	40,000
Beginning date of construction	2006
Completion date	May 23, 2008^[1]
Opening date	May 23, 2008^[1]

The North Avenue Bridge refers to the bridge carrying North Avenue (Illinois Route 64) over the north branch of the Chicago River on the north side of Chicago, Illinois. A new hybrid suspension/cable-stayed bridge opened on May 23, 2008, replacing an old bascule bridge that dated back to 1907.

1 Bridge replacement
2 Historic bridge overview
3 Similar bridges
4 External links
5 References

[edit] Bridge replacement

Due to age and the high cost of maintenance, a replacement fixed-span bridge was built through 2007–2008. The new bridge is a hybrid suspension/cable-stayed bridge of the same height but nearly twice as long in length. The original bridge was two lanes wide; the new bridge has four lanes plus bicycle lanes and sidewalks, helping to reduce congestion caused by the 40,000 cars/day that travel on the bridge.^[2] The new bridge was completed in 22 months, and cost US$25,000,000 to build.^[1]

[edit] Historic bridge overview

The historic bridge preceding the current bridge was a trunnion bascule bridge constructed in 1907. The bridge had an entire structure length, including approaches, of 273 feet, and a roadway width of 36 feet. The American Bridge Company fabricated the structure, with Roemheld and Gallery being the superstructure contractors. The substructure contractors were Jackson and Corbett. Chicago is a city that played an important role in the development of the bascule bridge, particularly the trunnion design. The North Avenue Bridge is one of the oldest of these bridges in Chicago along with some other neighboring structures on the North Branch of the Chicago River.

As required by Section 106 regulations, the city offered the structure to any interested parties for relocation and preservation elsewhere. With no interested parties, despite the significant historic value of the structure, the City of Chicago elected to demolish the historic bridge, marking a loss of a structure that paid tribute to one of Chicago's many significant contributions to the development of the United States.^[3]

[edit] Similar bridges

The Damen Avenue Bridge over the north branch of the Chicago River was a bascule bridge replaced by an arch bridge in 1999. The Cortland Street Bridge is regarded as one the most historically significant bridges in Chicago because it was the first of the trunnion style bridges built, with a 1901 construction date. A few similar bridges still remain on the North Branch of the Chicago River leading to Goose Island.