T.Y. Lin International (TYLI) was selected by the Illinois Department of Transportation (IDOT) to provide Construction Engineering Services for the Congress Parkway Bridge Rehabilitation over the South Branch of the Chicago River in Chicago, Illinois. Services included construction inspection, contract administration, coordination, and materials quality assurance testing.
The Congress Parkway Bridge is a dual double-leaf, trunnion-type bascule bridges spanning over the South Branch of the Chicago River, carrying both eastbound and westbound traffic on Congress Parkway. This movable bridge is one of the busiest bridges in Illinois, located in the heart of Chicago, originally built in 1956.
The purpose of the project was to improve the Bridge Condition & Load Rating by rehabilitating the bridge structural, electrical, and mechanical elements. Another purpose was to improve public safety by installing a closed deck system with a skid resistant surface along with enhanced lighting, and surveillance. The structural rehabilitation included floorbeam and truss repairs. The mechanical work included removal of all tie shaft machinery, replacement of the center lock machinery, machinery brakes, barrier gates, and traffic gates. The electrical work included the replacement of the main drive motor, the current control system with a PLC control system, facility lighting, power distribution panels and switchgear, cable and conduit routing, and traffic signals.
TYLI provided field staffs that were responsible for coordinating of shop drawing review; monitoring traffic control; verifying the contractor’s layout; preparing required documentation; verifying quantities; field inspection of materials; and coordinating material testing, all in accordance with IDOT procedural guidelines. Other responsibilities included: conducting weekly progress meetings; monitoring the contractor’s schedule; assisting in contract document interpretation; preparing field orders, correspondence letters, and proposed contract modifications for IDOT review.
This project included the replacement of an open grid deck with an orthotropic “closed deck” system. Due to existing truss conditions and elevations the fabrication and erection of the orthotropic deck required development of a revised attachment details which allowed for nominal shimming and field adjustment. The replacement of the deck system had a substantial impact on rebalancing the bridge. Additional counterweight analysis and design modifications were required due to a significant increase in the closed system deck weight.