Project Details
The 973.5 ft. long, $28.7 million 41st Street Bridge is to supplement the fully accessible, suspension bridge.
It features double-curved arch mono trusses to form large, graceful S-curves. The leisurely curves of the bridge recalls Olmsted’s original walkways for the Chicago Parks, while extending this park aesthetic westward over Lake Shore Drive. The horizontal and vertical curves of the bridge creates a graceful urban promenade that is visually dynamic from any approach. This bridge is designed to cross the Metra tracks and Lake shore drive. The bridge contains three segments in its total span. The segments are called East & West Approaches at the ends and Main span in the middle.
The main span of the bridge is suspended to cross over the Metra tracks and Lake shore drive. These are designed with steel Rib superstructure support achieving the objectives of both form and function. The longitudinal Rib-Girder support system accommodates the complex bridges need to curve both horizontally and vertically and provides the desired aesthetics.
East West Approach Spans
The bridges central Rib is fabricated from 30 inch diameter steel pipe, either 1 inch or 1 inch thick depending upon span and strength requirements. At the top of pipe added shear studs, which enable composite action between the steel and the paths 8 inch thick, 17 ft wide concrete deck.
Girder elements fabricated from steel plates are connected to each side of the steel Rib on 8 ft. 5 inch centres, and concrete fillets are used to maintain the slope in the deck. The railing systems are fixed over the reinforced curb along the bridge. Both the approach spans have stair for access.
Main Span
The main span has two spans with the length of 239 ft 5 inch and supported at both ends & middle. It is suspended at both sides of the middle support by using the Arches and suspended Hangers.
The main span has two Ribs at the edge of path way and Girders in between the Ribs. Main Rib is fabricated from 48 inch diameter steel pipe with 1inch thick, which is where suspended hangers are connected. Other secondary Rib is fabricated from 36 inch diameter steel pipe with 1inch thick. HSS 12.75×0.5 bracings are introduced between the Ribs to maintain the bridge stability.
The Arch is fabricated from 48 inch diameter steel pipe with 1inch thick and mounted over the Thrust block. Main Rib 48 inch & Arch location is changed to follow the S-Curve. The suspended hangers are connected from the Arch to the Main span Ribs.
