•by Alan McArthur
Last week's major bridge collapse in Minneapolis on Interstate 35 has caused many states to rethink the way they inspect bridges.
In Missouri, Gov. Matt Blunt called for an immediate inspection of the state’s 11 bridges with the same construction as the bridge in Minneapolis.
One of those bridges is in Platte County. The Fairfax Bridge across the Missouri River from Fairfax to Riverside contains deck truss construction on the approach portion of the bridge.
The inspections of all 11 bridges are expected to take up to five weeks to complete. The Fairfax inspection is scheduled to begin on Aug. 13.
Missouri and Platte officials are adamant that all local bridges are safe.
“If they’re open, they are safe,” said Chris Redline, assistant district engineer for the Missouri Department of Transportation, MoDOT, in Kansas City. “We won’t let the public pass over a bridge that is not safe. I don’t worry when I take my family across these bridges.”
Missouri has the seventh largest number of bridges in the nation with more than 10,200 bridges. Missouri also has the highest number of river crossing bridges with 55.
“Here in Missouri, we have plenty of bridges and roads that could use some work,” said Sam Graves, U.S. Congressman for this area. “However, considering the condition that Missouri roads were in just a few years ago, we have made remarkable progress. One recent study ranked Missouri’s roads 17th, a vast improvement from being 39th not too long ago.”
All bridges in Missouri are inspected by MoDOT every two years and given a sufficiency rating on a scale of 100. The rating takes into account factors such as age, condition, design, and daily traffic load.
In Platte County, three main entities maintain bridges, MoDOT, Kansas City Streets and Traffic Department, and the Platte County Public Works.
Platte County Public Works maintains 75 bridges that are over 25 feet long. According to public works director Greg Sager, the ages of bridges in Platte County range from having been built in 1920 to as new as 2006 and many are in various states of repair.
“Most of our bridges are in pretty decent shape,” said Sager. “Our bridges are safe, but we’ve got a dozen or so that have become functionally obsolete.”
Platte County inspects its bridges every two years and also uses the ratings from MoDOT.
“The sufficiency rating is based on a lot of factors,” said Sager. “It is not a safety rating. It measures if the bridge is sufficient for what it’s being used for.”
Some bridges are not rated with a 100 even immediately after construction.
“The Thomas Street Bridge in Weston will not receive a 100,” said Brian Scovill, assistant director of public works. “Less than 20 feet from the end of the bridge is the intersection with Blackhawk Street. The bridge will be brand new and still be scored lower because of the intersection.”
Even once a bridge receives a rating, the bridge can change due to many factors. Weather, traffic, and erosion all affect a bridge’s stability.
“The condition of bridges is constantly changing from day to day,” said Sager. “That’s the dynamic nature of the structures. It can be affected by weather problems.”
After the recent floods in June, all of the Platte County bridges were inspected for damage. According to Sager, these inspections found 22 bridges with damage or problems which need to be addressed.
“Lots of bridges last 50 to 100 years,” said Sager. “The majority of ours are nearing the end of their lives, and we watch them constantly. People’s lives are at stake. We take this very seriously.”
Sager pointed out that the transportation infrastructure of a community should be a major focus.
“The collapse in Minnesota shows us where our focus really should be,” said Sager. “If you don’t have a road or bridge to get to school it doesn’t matter how much money you put into the school.”
Another initiative of the governor is the plan to repair or replace 800 bridges in Missouri by 2012. The initiative is different from most because all of the 800 bridges are being bid in one contract.
The project is expected to cost between $400 million and $600 million. Under the project, contractors will bring all of the bridges up to good condition by 2012 and maintain them for at least 25 years afterward.
However, the plan has hit a legal pothole because of some performance bonds. The governor may call a special session of the General Assembly to help resolve the issue.
Under the initiative, 15 bridges in Platte County would be repaired. Those bridges include four along 45 Highway over the Bear, Sugar, Short, and Mission Creeks. The program would also repair a bridge along Route B over the Platte River and Route H over I-29. Interstate 69 over Line Creek is also included in the program.
One of the bridges not included in the project is the Highway 45 Bridge over the Platte River. According to Redline, the bridge scored a 12 on its last inspection.