The West Bound Blanchette Bridge replacement (a five lane bridge) was completed in only 10 months, it cost 64 million. It was completed early, and under budget.
The new canal bridge, is 4 lanes, has been under contraction since October 2011, and is not scheduled to be "completed" until until late summer of 2015 (although they plan to have it open to traffic late summer of this year) The total is estimated to be 104 million.
Granted, Missouri did reuse some of the foundations of the old bridge, and did not have to permanently reroute a major hi way, but the Blanchette is longer, contains more steel and pavement, and handles more traffic.