HBM Engineering Group, LLC played a pivotal role in collaborating with Omega III, LLC, a subcontractor for Illinois Constructor Corporation (ICC), providing essential structural engineering services. The focus was on preparing a comprehensive structural assessment report for the upcoming demolition of the IL 89 bridge over the Illinois River at Spring Valley in Bureau County, Illinois. The primary objective was to facilitate the reconstruction of the bridge. This report encapsulates the detailed structural assessment and analysis intended for the planned demolition.

General Bridge Information: Constructed in 1934, the IL 89 bridge boasts 19 spans, incorporating a mix of concrete slabs and steel trusses. The first six approach spans and the last eight approach spans consist of a 7 ½” cast-in-place concrete slab on four (4) W24x62 structural steel beams supported on multi-column bents on concrete piles. The middle five spans are Pennsylvania steel trusses with a 7 ½” cast-in-place concrete slab on four (4) W18x60 structural steel stringers supported on W30x116 floor beams supported by six (6) two-column piers. The truss span wall Piers 1, 2, 3, & 6 are supported by timber piles while Piers 4 & 5 are supported on spread footings on rock. A Type T-1 (modified) railing exists at each edge of the deck. The bridge is 1775’-7 3/8” back-to-back abutments and 23’-4” out-to-out of the deck and has no skew with respect to the roadway alignment. Superstructure and substructure bridge components to be demolished include: railing, deck, beams, piers, and abutment removal within the job limits. A critical aspect of the project involves maintaining ongoing traffic on the existing structure during the construction phase of the new bridge, with the eventual shift of traffic to the newly constructed bridge preceding the commencement of the demolition.