Jul 25 2006
In a city famed for the quantity and variety of its bridges, cable-stayed and suspension bridges have been noticeably absent, but no more. James McHugh Construction Co. has begun the preliminaries to erect a hybrid cable stayed/suspension bridge over the Chicago River at North Avenue, company officials announced.
An unusual blend of a self-anchored suspension bridge and a cable-stayed bridge, the North Avenue Bridge will be one of the first such hybrid systems in the country, according to Mike Gould, McHugh senior vice president of infrastructure construction. The City of Chicago's Department of Transportation selected McHugh as general contractor for the $19.7 million project. HNTB Corp. is the design architect, with Chicago-based Muller and Muller the consulting architects. McHugh has contracted with
Chicago-based H.W. Lochner Inc. and Tampa, Fla.-based Bridge Concepts for construction engineering. Most cable bridges are either suspension -- think Golden Gate Bridge, with the "draping" look -- or cable stayed -- think Sunshine Skyway, with its straight lines. The clean lines of the North Avenue Bridge will feature both, with stainless steel cladding and architectural uplighting.
Actual construction of the bridge will comprise only the last part of this multiphase project. McHugh first will erect a temporary vehicular and pedestrian bridge over the Chicago River. It is scheduled for completion in August. Next, the team will demolish the old bridge, an inoperable bascule bridge, through November. After that, the contracting team must relocate and adjust utilities. Finally, erection of the bridge will take place in winter of 2006 through spring of 2007, with completion targeted for August 2007.
The new, 420-foot span actually features three separate segments. The east and west approach spans will be supported by the cable stays. The middle span, over the river, will be supported by the suspension cable system. Both of these systems will share two sets of support pylons, constructed of built- up, rolled stainless steel plates.
As part of the project, McHugh will create wide, accessible sidewalks and landscaped plazas around and beneath each pier of the bridge on both sides of North Avenue and the riverbanks.