"As of Oct. 16, 31 of the 40 caissons, two of the 10 footings and the first of the 10 columns are filled with concrete."
Here's the word from MnDOT last Friday:
"Bridge foundations work in the St. Croix River is on track to be complete by early 2014. A major part of this is drilling 40 caissons into the muck and bedrock at the bottom of the river. Caissons are 9-feet diameter steel casings. Crews drill them up to 120 feet below the river surface, then fill them with rebar and concrete to create solid foundations for the new bridge. Then, crews pour a concrete footing and a column at each pier location that will eventually attach to the bridge superstructure. The columns will be visible and stick up about 15 feet above the water’s surface."Completing all foundations work at Piers 8-12 requires 40 caissons, 10 footings and 10 columns."