MinnDOT says one less set of piers needed for bridge

• Load testing

On Thursday, Aug. 9, cement trucks were being ferried to a barge platform on the river where a piling is being constructed to test the amount of weight and resistance the bedrock will bear.
• New bridge

The Minnesota Department of Transportation was planning for six sets of piers in the water when this drawing of the future St. Croix River bridge was made.

Talk about it

Minnesota transportation officials say they’ll reduce the numbers of piers that will support the new four-lane bridge over the St. Croix River between the town of St. Joseph and Oak Park Heights, Minn.

Project director John Shiglo says five sets of two piers each will be placed in the water, one set fewer than originally planned. Another set of piers will be placed on land on the Wisconsin side.

Each span will be lengthened by 100 feet to around 575 feet. Shiglo says it will give the bridge a more slender look.

He says it will also help the environment, save time and possibly millions of dollars.

It could take up to four months to build a single pier. The savings would come off a project that was expected to cost between $574 million and $690 million.

The bridge construction is estimated to cost $280 million to $310 million. Highway construction and other expenses make up the rest of the cost. Wisconsin and Minnesota are splitting the bill.

On Thursday, cement trucks were being ferried to a barge platform on the river where a piling is being constructed to test the amount of weight and resistance the bedrock will bear.

A shaft 8 feet in diameter was drilled into the river bottom, and then at least 30 feet into the bedrock. It was lined with a steel casing to keep the dirt in place, and is now being filled with rebar and concrete.

Once the piling is constructed, it will be tested for how much weight it can bear and how much pressure it can take from the side. The testing determines what type of piers are needed to hold the bridge deck.

More information about the bridge construction can be found at www.dot.state.mn.us/stcroixcrossing.

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