The existing bascule bridge crossing the Chicago River at North Avenue is inoperable. HNTB's Chicago office proposes to replace it with a hybrid self-anchored suspension and cable stayed bridge with aesthetic and architectural features being a significant element of the design.
The proposed bridge will be 420 feet long with a 252 foot center span and two 84 foot back spans. The suspension and cable stays will be supported by two steel "twin oval" shaped towers at each river bank. The bridge deck will be a longitudinally post-tensioned, cast-in-place concrete deck supported by variable depth steel box girders. The middle half of the center span will be supported by the suspension cable and hangers while the cable stays support the remainder of the center span and the back spans.
The completed structure is intended to be a signature bridge for the surrounding community. The design of the bridge is expected to be complete by this fall and the construction by December 2005.
The Structural Engineers Association of Illinois (SEAOI) will host a dinner meeting featuring a presentation by HNTB about the proposed reconstruction on Tuesday, Nov. 2, at the 410 Club, Wrigley Building, 410 N. Michigan Ave., costing $40. Reservations are required; call Donna Childs at (312) 372-4198. Visit seaoi.org.
This article was originally printed in the bulletin of SEAOI.
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