The 2025 ACEC/Iowa Engineering Excellence Awards winning projects in the Transportation Category: Transportation Grand Place Award (1st Place in Category)
Firm: WHKS & Company Client/Owner: Iowa Department of Transportation and Illinois Department of Transportation Project: Centennial Bridge Repair
After cracks were identified in the expansion bearing rollers for the arch spans of the Centennial Bridge, WHKS provided services for the design of a replacement expansion bearing and the bearing replacement procedure.
The bearing replacement project presented significant challenges, as it involved repairing a tied-arch structure with minimal modifications to preserve its appearance. The Illinois Department of Transportation (IDOT) hired WHKS to design a custom replacement bearing and jacking system to replace corroded and cracked expansion bearings.
The bearing replacement procedure required analyzing portions of the existing bearing assembly with a finite element analysis to ensure that the jacking procedure would not overstress the existing bearing. Jacks were detailed to sit on sliding steel plates that would allow them to move with the structure as it expanded and contracted with changes in temperature.
WHKS also developed a specification that included installing strain gauges on the existing bearing to monitor stresses during jacking.
By utilizing components from common bearing designs, WHKS developed a custom bearing solution that fit within the limited space of the existing rollers. The system’s connections and careful planning minimized installation time and reduced the overall impact on traffic. The project not only maintained the bridge’s historical aesthetic but also extended the structure’s service life with minimal cost and disruption to the public.
