CSAH 25 Bridge over the Root River

Houston County, Minnesota

Mead & Hunt relocated a .33-mile stretch of roadway and bridge approximately 250 feet downstream from its original location over the Root River. 

A hydraulic analysis was conducted at the project site on the river, which has a 100-year flow rate of 57,000 cfs.  It was determined to provide a minimum of one foot of freeboard over the 100-year flood elevation.  The roadway had to be raised about 15 to 20 feet over existing conditions.  The new bridge is a four-span, 470-foot, 54-inch prestressed concrete girder bridge.

The substructure consists of parapet-type abutments with expansion bearings and hammerhead piers supported by 12-inch cast-in-place concrete piling.  Special care was used in the design of the piers to account for possible scour.