Lafayette County retained Ayres Associates to design the replacement of the CTH U bridge over Ames Branch.
The structurally deficient single-span concrete deck girder bridge built in 1917 was replaced with a new 38-foot-long single-span flat slab bridge. A flat slab was chosen to meet freeboard requirements between the structure bottom and water surface. The new bridge is 30 feet wide, providing 10 more feet of roadway clear width than the replaced structure, accommodating wider lanes and shoulders.
A reinforced concrete box culvert south of the crossing provided our design team an opportunity to evaluate several alternatives on how to best protect the proposed structure. The design team determined the existing box culvert was narrow enough to span with beam guard, eliminating the need to extend the box culvert as part of this project.