Preliminary work on the $676 million bridge project over the St. Croix River will begin Wednesday as workers begin setting up on the river for pier testing.
A barge laden with heavy equipment will move onto the river where the bridge will cross at Oak Park Heights, said Mary McFarland Brooks, a spokeswoman for the Minnesota Department of Transportation.
Crews will document how much weight the bedrock can hold by hammering two 24-inch piles and two 42-inch piles into the river bottom.
Residents might hear noise from 7 a.m. to 5:30 p.m. on weekdays, but McFarland Brooks said the start of the pounding depends on preparations. Most of the noise will come in the first four days, she said.
The testing should be completed by mid-August.
The "load testing" will provide information about soil conditions that will determine the bridge's foundation design. The four-lane bridge will have six sets of piers in the water -- two legs to each set. A seventh pier set will support the bridge on the Wisconsin side of the St. Croix.
MnDOT and the contractor, Carl Bolander and Sons of St. Paul, will test the river daily to monitor water quality.
Details are available at www. mndot.gov/stcroixcrossing and the on St. Croix Crossing Facebook page.