Iowa ranks 30th of all states in population but has the dubious honor of being tops in the number of structurally deficient bridges, according to a new national report.
Of Iowa’s 24,184 bridges, 4,968 — or 21 percent — are classified as structurally deficient, according to a report released Thursday by the American Road & Transportation Builders Association. This designation means one or more of the key bridge elements— such as the deck, superstructure or substructure — is considered to be in poor or worse condition.
Despite extensive repairs in 2014 and 2015, the 77-year-old Centennial Bridge connecting Rock Island and Davenport is the most-traveled structurally deficient bridge in Iowa, according to the report.
“Just because a bridge is structurally deficient does not mean it’s not safe to travel,” said John Wegmeyer, project implementation engineer for Illinois Department of Transportation District 2. He said a main reason the four-lane Centennial Bridge is considered structurally deficient is its lack of shoulders for vehicles to pull off.
“It’s been something talked about for years. We know we need to replace the bridge,” he said of the arched span that averaged 32,000 daily crossings last year. “There’s only so much money available. We try to set priorities in the area, and now the I-74 bridge is the No. 1 priority.”
Thursday’s report found the average age of a structurally deficient bridge is 67 years old, compared to 39 years for nondeficient bridges.
From June through November 2015, General Constructors Inc. of the Quad Cities repaired the Centennial bridge deck as part of a $3.35 million project. In 2014, the bridge was closed August to October to replace two beams that span the width of the bridge. Initially set to reopen Sept. 6, 2014, additional repairs were required, including its handrail and concrete median.
“There’s nothing we’re gonna do about the geometry” of the bridge, Mr. Wegmeyer said. “It will never get any better than that until can get a new structure. We’ve done a lot of repairs the last year or two.
“There are a thousand members of that bridge getting old — all the joints, everything riveted and bolted together,” he said. “We do an extensive investigation every year, inspections on the whole structure, and we’re making repairs to keep it serviceable, to keep it safe.
“Like the (Interstate) 74 bridge, the only way get much better is to replace it.”
Iowa and Illinois share the costs of maintaining Mississippi River bridges in the Quad-Cities. Iowa is leading the $1.2 billion I-74 bridge project planned to open in 2020. The new bridge between Moline and Bettendorf, just east of the existing one, will have two spans — each with four lanes and full shoulders.
Recently released U.S. Department of Transportation data states vehicles cross the nation’s 55,710 structurally compromised bridges — including about 1,900 interstate spans — 185 million times daily. State transportation departments have identified 13,000 Interstate bridges that need replacement, widening or major reconstruction.
To help ensure public safety, bridge decks and support structures are regularly inspected for deterioration and remedial action, the release said.
Thursday’s report also showed another Davenport bridge among the top deficient bridges in the state. The fifth most-traveled deficient span is Division Street over Duck Creek, built in 1963, which averages 20,000 daily crossings.
Other key Iowa findings in the ARTBA analysis:
— The state ranked second behind Rhode Island in the percentage of bridges deemed structurally deficient.
— 1,039 bridges, or 4 percent, were classified as functionally obsolete, meaning the bridge does not meet design standards in line with current practice.
— Federal investment in Iowa supported $1.6 billion of improvements on 2,088 bridges between 2005 and 2014.
— Over the last 10 years, 1,915 new bridges were built and 270 underwent major reconstruction.
— 14,829 bridges have been identified as needing repairs; total estimated cost is $7 million.
Illinois ranked sixth in deficient bridges with 2,243, or 8 percent of its inventory.
The inventory of deficient bridges has declined 0.5 percent since the 2015 report. At that pace, it would take more than two decades to replace or repair all of them, according to ARTBA chief economist Alison Premo Black who conducted the analysis.
“America’s highway network is woefully underperforming,” Dr. Black said. “It is outdated, overused, underfunded and in desperate need of modernization. State and local transportation departments haven’t been provided the resources to keep pace with the nation’s bridge needs.”
Source: QCO Online