The March 2001 study into the bridge that collapsed Wednesday evening advised against refurbishing the bridge because of "high costs."
The StarTribune of Minneapolis/St. Paul has posted the results from a March 2001 engineering study (PDF) conducted by engineering faculty at the University of Minnesota - Twin Cities on the I-35W bridge over the Mississippi River. The document is full of engineering details that are well over my head, but this passage from the abstract is a little chilling, given today's events:
The bridge's deck truss has not experienced fatigue cracking, but it has many poor fatigue details on the main truss and floor truss system. The research helped determine that the [sic] fatigue cracking of the deck truss is not likely, which means that the bridge should not have any problems with fatigue cracking in the foreseeable future.[Boldface added.]
As a result, Mn/DOT [the Minnesota Department of Transportation] does not need to prematurely replace this bridge because of fatigue cracking, avoiding the high costs associated with such a large project.
For context (of arguable relevance), the executive branch of the Minnesota state government is currently run by Tim Pawlenty, a strongly anti-tax Republican who is rumored to have designs on the vice-presidency. Pawlenty has of late come under harsh attack from progressives for obstructing sufficient funding for transportation and infrastructure--including a recent veto of an infrastructure-funding bill passed by the majority-DFL (Democrat Farmer Labor--the state Democratic party) legislature.
It should be noted, however, that the March 2001 study quoted above predates Pawlenty's term; when the above-quoted study was performed, the head of the state executive branch was independent Governor Jesse Ventura.