Veteran's Memorial Tollway (I-355) Bridge over the DesPlaines River Valley


Illinois Tollway


Walsh Construction


Lemont, Illinois

Key Staff

Sandor Ferenczi, SE

BB&A partnered with Janssen & Spaans to provide design-build engineering services for the major structure in the Illinois Tollway's 12.5 mile southbound extension project - the 1.3 mile, 6 lane bridge over the Des Plaines River Valley. The bridge is the first in the state of Illinois to use post-tensioned, precast, prestressed concrete bulb-T girders.

The main challenge was to design the bridge with minimal interference to all of the entities located beneath it: the Des Plaines River, I&M Canal, Sanitary & Ship Canal, several railroad lines, and forest preserve land.
The final design employed a combination of 102" post-tensioned spliced and 90" pretentioned Bulb-T beams, which allowed for post-tensioned span lengths of up to 270 feet, significantly longer than traditional beams would allow.

The bridge has a total of 34 piers and 35 spans (18 pretensioned, 17 post-tensioned). The tallest pier cap is 82 feet above grade, and the bridge deck rises to 90 feet at the highest point, allowing the endangered Hine's Emerald Dragonfly to fly safely beneath the bridge, away from the flow of traffic.