September 1, 2009: Despite being less than 50 years old, the IA 136 bridge over the Mississippi River at Clinton is classified as poor condition and functionally obsolete.
Without any fanfare, the state has put a valuable resource online: A visual database of Iowa’s 24,000-plus bridges, at every level. It’s “real-time” inasmuch as it uses the most recent data available.
There was a press release/blog post on the DOT’s “Transportation Matters” site, but I found out about this via a trade publication, Equipment World magazine. That site, however, didn’t have the link to the bridge site, so it took more digging!
The Iowa Bridge Condition Index for each structure is set through an algorithm created by Scott Neubauer, the Iowa DOT’s state bridge maintenance and inspection engineer, according to the blog post. It takes into account condition, serviceability, and weight restrictions. It does not include the sufficiency rating number, which unfortunately hasn’t been updated in a PDF since 2010.
Through those key components, I scanned the map for the 33 state-maintained bridges in “poor condition” and hit 31 of them. There are 48 classified as structurally deficient, and 10 closed.
Among the important bridges in “poor” condition are many over the Mississippi River: the Black Hawk Bridge (IA 9 at Lansing), Julien Dubuque Bridge (US 20 at Dubuque), US 30 and IA 136 at Clinton, and the Savanna-Sabula Bridge, whose replacement should open on or about Halloween this year. On the other side of the state, both the IA 175 and I-480 bridges are on the list.
Nine of the bridges in poor condition are slated to be replaced over the next five years, including Business US 61 over IA 22, which just had a meeting last month.
There are five state-owned bridges that are both in poor condition and structurally deficient. Two of them, US 30 over the railroad at Grand Junction and old IA 207 over I-35, are being replaced this year; a third, IA 415 over Northwest 66th Street in Polk County, will be removed in 2019. The other two, however, are impossible to replace without major disruptions — they’re the US 67 Centennial Bridge over the Mississippi River and the Gordon Drive Viaduct in Sioux City.