|
Key Facts |
Bridge Name | Type | Road | Location | City | Crossing |
|
Franklin Street Bridge |
Bascule (Truss) |
Franklin Street |
Cook County, IL |
Chicago |
Chicago River |
|
Technical Facts |
|
Construction Date |
Rehabilitation Date |
Structure Length | Trunnion-Trunnion Length | Clear Span | Bridge Width | Roadway Width | Approach Spans | Navigational Vertical Clearance |
| 1920 | 2002 | 320 Feet | 251.83 Feet | 220 Feet | 62 Feet | 38 Feet | 5 Steel Stringers | 18.7 Feet |
The last bridge to cross the Chicago River before it splits into the north and south branches, this bridge crosses the river at an angle compared to the bridge east of its location, and lies in the shadow of the massive Merchandise Mart building.
This bridge is similar to the nearby Clark and La Salle Street Bridges, although the trusses are not quite as high and impressive. The Grand Avenue Bridge is an example of an older bridge that utilizes this same design, but has a more clunky appearance. The unusual shape of these bridge comes from the fact that each leaf of this double-leaf bascule bridge is essentially cantilevered out from the abutments, meaning that the each end of the bridge is supporting its half of the bridge out to the center independently of the other half of the bridge. Bascule bridges must function this way since they cannot be connected in the center.
Some of the bascule bridges in Chicago have less than interesting railings for the cantilevered sidewalks present on them, but this bridge is among the bridges that do have interesting railings. This sets this bridge above a bridge like the nearby Clark Street Bridge.
This trunnion bascule bridge, which features a pony truss superstructure was built in 1920. The contractor for the substructure of the bridge was the Great Lakes Dredge and Dock Company. The superstructure contractor was the Ketler-Elliot Company. The original electrical equipment was installed by C.H. Norwood.
