August 23, 2007 at 7:14 a.m.
MnDOT's Kent Barnard looked into the Trunk Highway 243 bridge inspection report for the County Press.
Barnard explained the state's monitoring of the inspection findings will continue but there are no issues that are "imminent." The 243 bridge has no programmed work until 2010. At that time the bridge deck will be overlaid (resurfaced.) Barnard guessed that if there are defects that can feasibly be addressed along with this deck project MnDOT will look into those.
He stressed that none of the inspection conclusions posed any immediate concerns about bridge safety.
The 18-page inspection report, (plus photos and diagrams) several times refers to rocker bearings being at "maximum expansion." The 44-year-old bridge utilizes a construction method that's not used anymore, where rocker bearings sit atop the abutments and the bridge sits atop the rocker bearings. "Rocker bearings appear to be functioning as designed," the inspector wrote.
Deck drains are seriously corroded and the bridge deck is being exposed where the drains are disappearing. The drain downspouts directly beneath the deck (see photo) have "severe section loss." Page five in the inspection report noted the "deck has started to deteriorate" where half the downspout connection assembly, at specific points in each span, have rusted away.
Barnard mentioned that bridges built today do not drain directly, but are constructed with a stormwater collection system. If the bridge over the St. Croix were totally rebuilt these drains would go away. At this time there is no plan to replace or reconstruct the drains.
The riverbanks drop-off steeply where the bridge connects on both sides of the river to Trunk Highway 243. Under the bridge there is soft sand and dirt, shrubby growth, some riprap and cindered logs where campfires have been enjoyed beneath the bridge.
The inspectors noted a need for "slope protection" in their summary.
"Slope protections of some type should be placed at both abutments (east and west sides of river). The Press attempted to photograph the west side where a 10 foot section of plate beam was installed to control erosion, but the quality of the photo didn't adequately show how the beam is no longer supported by soil.
"Side slopes" also have little erosion protections, the inspection summary notes. The inspection summary adds, "Contract should be let to place slope protection."
Barnard said this is not part of the program currently scheduled for the bridge. If there should be a drastic change in the riverbanks, MnDOT will respond. Again, monitoring will be stepped-up on this site.
A visible concrete patch on one of the piers was also noted in the inspection report, but the four piers were categorized "in good condition below the water."
The Osceola bridge paint is in good condition. It was last painted 10 years ago (zinc system) and the paint is only 2 percent unsound, according to the report.