CATEGORY: Structural Systems

ENTERING FIRM: Stanley Consultants

OTHER CONSULTANTS: Lorig Construction Company, Baxter & Woodman

OWNER: County of McHenry

DESCRIPTION: Johnsburg Road Bridge suffered from extensive deck and beam cracking, spalling and exposed prestressed strands. Though just 28-years old, the precast, prestressed single span box-beam bridge had portions of its deck closed to vehicle traffic because 4 ofits13 underlying beams were deemed unsafe. A full replacement could take 5 to 6 years, but the County was concerned that the bridge deck may not have that many years of life left, and a more expedient solution was needed. The challenge was to determine viable solutions and complete the project in months rather than years. Stanley Consultants solution was to replace the bridge superstructure while retaining its substructure, which were in good condition. That approach avoided all work within the flood plain. The County shifted to 100 percent local funding, avoiding the lengthy NEPA process required for federal funds. In order to re-use the existing abutments, the superstructure was replaced in kind using precast prestressed concrete box-beams but placed using innovative techniques to prevent future cracking and deterioration. The result: The project came in under budget and ahead of schedule with the bridge closure lasting just 32 days. The County is thrilled with the results.