IDOT I-90 Westbound

GRAEF and its subconsultant team completed a single span bridge design over Higgins Creek as well as the Westbound Collector Distributor (CD) Roadway design from northbound I-490 to WB I-90 in 2018. The bridge and Westbound CD Roadway were let in separate contracts, which were each part of the Tollway’s objective of accelerating designs so that the work would be let in 2018. Complete topographic survey as well as incorporation of the recently constructed I-90 improvements were a part of the project scope. Given the limited right-of-way available, GRAEF’s team also designed two retaining walls on either side of the Higgins Creek bridge. These walls permitted the project to be designed with a minimal amount of right-of-way acquisition. A critical aspect of the project included the relocation of the existing IPDC building as well as relocation of existing fiber optic utilities that were in conflict with the proposed CD Road pavement. GRAEF also worked with the Design Corridor Manager to secure necessary environmental clearances and incorporate corridor-wide requirements into the bidding documents.

The proposed bridge design includes pre-cast concrete girders (the new wider and shallower PPC IL-Beams) and provides for three Westbound CD Road lanes with full shoulders. The bridge is adjacent to and independent of the existing WB I-90 bridge over Higgins Creek. A 90’ long cast-in-place retaining wall at the northeast corner of the bridge is also included in the bridge contract (I-18-4695). GRAEF’s bridge designers worked closely with the GRAEF Geometrics Engineer and Drainage Engineer to assure a complementary design with the separate CD Road contract (I-18-4699). GRAEF also coordinated with Infrastructure Engineering Inc. since they designed the Eastbound CD Road bridge. Consistency was important for the Westbound and Eastbound CD Road bridges, since they were let in the same contract.