Sauk Rapids Regional Bridge

Location: Sauk Rapids, MN

Clients: SRF Consulting Group, Inc. (Design) and WSB & Associates, Inc. (Construction)

Services: Geotchnical evaluation, construction materials testing, quality assurance testing

Year: 2007

Considered the first downtown transportation project of its kind nationwide because of the large amount of necessary business relocations, the new Sauk Rapids Regional Bridge had an especially large project scope. We were retained to provide the geotechnical evaluation, construction materials testing and quality assurance testing. 

This $56 million project had many engineering challenges. To drill additional soil borings and determine the bedrock depth under the bridge alignment, crews had to build rock pads across the Mississippi River and place work bridges between them to gain access. The bedrock formation was also much deeper than originally believed; too deep for the planned 5-foot diameter drilled shafts, so we drilled 50 16-inch pipe piles to reach the bedrock. To inspect the soundness of the underwater bedrock, we invented a unique method consisting of a probe with a special television monitor that allowed our project engineers to see any rock fractures that could cause excessive pier deflections.  

Our field technicians also faced challenges. Because of the hot summer temperatures, they had to conduct concrete testing offsite at a local ready mix plant to pour at night when the temperatures dropped. The materials testing included concrete batch plant inspections, soil compaction tests, lab testing and concrete testing services for the bridge piers and deck.