Inside the Tollway
With a variety of highly impressive bridge projects underway, the Illinois Tollway was invited to share its expertise at this year’s annual bridge symposium hosted by the Structural Engineers Association of Illinois and the National Council of Structural Engineers Association.
The July virtual conference featured a webinar by Acting Chief Engineering Officer Manar Nashif and Deputy Chief of Program Implementation Lanyea Griffin highlighting the Mile Long Bridge and Burlington Northern Santa Fe (BNSF) Railway bridge projects on the Central Tri-State Tollway (I-294) and new interchanges for the new I-490 Tollway.
The Tollway webinar provided a general overview on the status of major bridge projects underway on the I-490 Tollway and I-294. In addition, a webinar by Tollway project manager exp U.S. Services Inc. focused on technical aspects of the design of ramp bridges on the I-490/I-90 interchange.
The $500 million Mile Long Bridge Project is one of the Tollway’s most ambitious bridge projects in the Move Illinois Program. The two bridges that make up the Mile Long Bridge traverse two major railroads, three waterways, local roads and major distribution facilities for UPS and BNSF. A critical piece of infrastructures on I-294, the Mile Long Bridge serves up to 150,000 vehicle a day.
Construction of the two new, wider 4,800-foot-long bridge structures started in 2019, with the northbound structure completed in 2020 and the southbound structure scheduled to be completed in 2022. Each of the new structures will have fewer piers to reduce the environmental impact on the waterways and industrial areas below. Each structure will have 27 spans supported by 26 piers, compared to the 53 piers supporting each of the original structures.
The Mile Long Bridge is being built to accommodate the foreseeable future needs of the traveling public to the greatest extent possible, with the new structures expected to last as long as 100 years.
Further up the road, the Illinois Tollway is reconstructing the BNSF Railway Bridge, which carries the railroad over I-294 between Hinsdale and Western Springs, to accommodate the reconstruction and widening of the Central Tri-State Tollway.
The existing bridge will be replaced with a longer, wider two-span steel beam structure that will accommodate four tracks and allow for reconstruction and widening of the Tollway underneath. The new fourth track on the bridge will be used for maintenance purposes by BNSF.
Working in coordination with the BNSF Railway, the Illinois Tollway is providing for uninterrupted commuter rail and freight operations during bridge reconstruction. BNSF and Metra trains are currently using a temporary bypass bridge while construction of the new bridge is underway. On average, approximately 104 Metra and Amtrak trains cross the bridge daily, as well as 52 daily freight trains.
As part of the construction of the new I-490 Tollway, new interchanges will connect to I-90, I-294 and the Illinois Route 390 Tollway.
The I-490/I-90 Interchange will significantly improve travel and enhance mobility throughout the adjoining communities by connecting the new tollway to the Jane Addams Memorial Tollway (I-90). The $120 million project to construct the new interchange will consist of four ramps, including a ramp bridge over I-90 connecting westbound I-90 to I-490 and will also include construction of a new multi-span bridge that will carry I-490 over the Metropolitan Water Reclamation of Greater Chicago’s Touhy Avenue Reservoir south of I-90.
The new I-490/IL 390 Interchange will feature four flyover ramps connecting the two Tollway roadways, along with two ramp bridges connecting to the west side of O’Hare International Airport. The $340 million project includes construction of three miles of I-490 Tollway mainline roadway along with 16 ramps and 15 bridges to deliver full mobility on the west side of the airport.
Four flyover ramp bridges will include 24 concrete piers and 24 steel girders to support the new ramps with a total length of 3,800 feet. Bridge decks will be 50 feet above grade at their highest points. In addition, the two ramp bridges connecting to the west side of the airport will both total 1,900 feet in length with 17 steel girders to support the new ramps.