As of April 2017, the Shaw Road Bridge in Jones County, IA is closed indefinitely due to a fracture in the north span.
Sources:
http://monticelloexpress.com/content/farmers-express-issues-... (Full article is paywalled, but the summary mentions the approximate time of and reason for the closure).
http://www.jonescountyiowa.org/utilities (Source of the "closed indefinitely" qualifier).
Shaw Road bridge has been demolished 12/15/2017.