The old Wakota Bridge was been a southeast metro area landmark since it was built. While the bridge was still sound, it was simply overwhelmed by traffic, with significant backups many hours each day. The new bridge combined with the US-61 freeway upgrade will dramatically improve quality of life for anyone who has to commute through that area. The new bridge will also include a bicycle path. This will improve the bicycle trail connections in the east metro area given that there are no other bicycle river crossings in that area.
The was to build the west bound span just north of the old bridge. All I-494 traffic would be moved to the new span, and then the old span would be imploded. Due to the large volume of barge traffic, the old bridge would have to be removed during the winter off season for navigation. Once the old bridge was gone, the east bound span of the new bridge would be built.
The west bound span was built like a huge teeter-totter. Several piers were erected, and the bridge structure was built both directions from each pier. Construction crews had to be careful to build the same amount on both sides of a pier to keep the structure in balance. Once the bridge sections made connection with each other, the delicately balanced sections would join to create a very strong bridge. The west end was especially tricky to built. First, there are two interchanges very close to the bridge that had to remain open. Next, the I-494 highway was in the way and had to be moved south a dozen feet. And then there is an active railroad and a street that intersect directly under the bridge, both of which had to remain open. That section of the bridge was supported with steel falsework.
The bridge project was cruising right along, until MN-DOT noticed that the new bridge was starting to crack. In fact, it was in danger of collapsing under its own weight. It turns out that the bridge designer made a key mistake and underestimated the amount of steel rebar that needed to be installed in the bridge. This caused the edges of the bridge to droop a bit, and the extra stress was cracking the concrete. Construction was shifted into low gear until a solution was found. That solution was two fold. First, the design was modified so all remaining construction had enough rebar. Second, the already built section was retrofit with a number of steel cables under high tension. The cables pulled the sides of the bridges together. The weight of the sides pulled the cable tight, which caused the cable to push down on the stronger center back bone of the span. This transferred the weight off of the sides, stopped them from drooping, and reduced the stress on the concrete. Engineers say it will not impact the life of the bridge, but only time will tell for sure.
The net result of the project is that the new bridge was not ready for the winter of 2005/2006, so the old bridge could not be removed until the winter of 2006/2007. That pushed the completion of the second span back to the fall of 2008.
Note—yet another problem with the Wakota Bridge project. MN-DOT and Lunda Construction were unable to agree on a price for building the eastbound span over the Mississippi River. As a result, MN-DOT canceled the contract with Lunda, and has decided to rebid the bridge. Lunda will complete its current work and remove the old bridge. It may take as long as a year to rebid the bridge, pushing the completion out to 2009 to 2010.
Note—yet more problems. First, it appears that Lunda was correct in their estimate of $60-million to build the second span, and that Lunda will receive about $10-million in a breach of contract settlement. MN-DOT has about $40-million left to finish the project, which puts the second span in danger of being delayed years to find the additional funding. Second, MN-DOT is concerned about a cash flow problem related to the new I-35W bridge. The money is needed early in the project to pay the contractors as they go, but the federal money is not available until later in the project when the bridge is substantially complete. One solution is to raid the Wakota Bridge money to keep I-35W moving, and delay the Wakota Bridge until the funding can be replaced. As a result, one wonders if the second span will ever be built.
As of January 2008, MN-DOT has requested and opened bids for the second span. The low bidder is, not surprisingly, Lunda Constructure of Black River Falls, Wi. Thier $60-million bid is within a few hundred thousand dollars of their earlier bid that resulted in them being fired from the project.
