A tragic bridge collapse in northern Kentucky

 

It is with sadness that I report the collapse of the South Fork Grassy Creek Bridge in Pendleton County, Kentucky. I first photographed the span in the winter of 2012 and revisited the collapsed bridge Sunday. Thanks to reader Brian for the tip on the collapse.

 

Constructed in the early 1900s by an unknown company, the Pratt through truss carried Lightfoot Fork Road - later known as Kentucky Route 1657 over the South Fork Grassy Creek. It was closed to traffic in 1964 when a new bridge was built approximately 1/4-mile downstream.

 

At approximately 5:15 PM October 28, 2012, the bridge collapsed when Craig Ruber of Dry Ridge attempted to cross while hauling hay. Ruber, a local farmer who served on the Grant County Farm Board and who was the owner of Ruber’s Landscaping and Lawn Care, died on the scene.

 

Below: Photographs from the winter of 2012.

 

 

 

 

 

 

 

 

 

Below: Photographs of the bridge post-collapse. These were taken with permission. An effort was made to find any steel manufacturer stamp or date, but most of what was etched has been covered with layers of rust.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

:(

Ohh man you scared the shit out of me. I thought people died. But I guess this is a huge tragedy for most of us

One individual did.

That's sad.

 

Wow! I could spend hours looking at these photos. Thanks for taking the time, and thanks for sharing. Sherman, you caught a before-and-after series that is very uncommon. The broken pier especially is striking.

 

I have a question, though: was the victim driving a vehicle, and if so, what happened to it? Was some of the damage to the bridge due to removal of the vehicle?

Hi - thanks for the warm comments again.

 

The individual was driving a John Deere tractor with a bale of hay. It collapsed about 2/3 into the span. I am not sure where or how the vehicle was extracted - it was removed before I was able to photograph it. It could not have been backed up the bridge and over the abutment as that had separated by about 1' and the grade to the abutment was very steep - not even walkable. There was not really space to extract it from the side unless a hanging component of the bridge was swung out. It may have been that a part was cut to remove the tractor but I did not see any immediate evidence of that.

 

I talked to a bridge engineer today who looked at my photographs. It looked to him as if the load of the tractor caused the span to collapse, which led the abutment to pull out by 1'. The abutment was already in poor condition and was cracked.

I'm sure that crossing was permitted "at your own risk" and probably nobody around there thought anything about taking farm equipment across it. It had always held, after all.

 

The old Oregonia Road bridge collapsed here (in Oregonia, near Lebanon) in March, 2001. Same situation - the bridge was closed to all vehicular traffic, although foot traffic was permitted. In this instance it just collapsed of its own accord. I was one of the local rubberneckers who drove by that weekend to check it out. The construction looked quite similar to this bridge.

Horrible that someone died.  Just observations..... Looks like the bridge failed in torsion and the bearings just pulled up and out of the opposite abutment. I'm not sure the cracked pier is primarily to blame for the incident, but it's telling of the condition of the bridge.  Your photos of the bridge piror to collapse show some distortion of members that create uneven load distribution over the bridge.  Just one connection failing is enough to twist the bridge and cause collapse.  It's like it bent under the load of the tractor, listed and sheared the bearings off the pier then plunged downward.  It's possible the cracked pier could have assisted by giving under tension forces of the twisting truss...but technically a truss should be able to perform on its own.

Wow, there are so many modes of failure in those photos, it is hard to work out which happened first.

 

Here's what I think caused the collapse:

 

Before:

<img src="http://bridgestunnels.com/wp-content/gallery/south-fork-grassy-creek-bridge-ky-1657/20111030-_dsc2503.jpg" alt="" class="bbc_img" />

Clearly, the gusset plate is nearly separated by severe section loss due to rust. Its interesting that the rust was cutting a fairly clean line across the plate.

 

 

After:

<img src="http://bridgestunnels.com/wp-content/gallery/south-fork-grassy-creek-bridge-ky-1657/20121104-_dsc3300.jpg" alt="" class="bbc_img" />

Here the gusset plat has separated.

 

Note that these two photos may not be of the same joint, but it is likely that all of the lower chord joints had similar defects.

 

The first separation may have happened here, or possibly the corresponding joint on the other truss:

 

This joint is underwater in the after photo. This would also be the joint with the highest loading at the time of the collapse, assuming that the tractor was positioned just ahead of the hay, which can be seen in the photos.

 

Once this joint was broken, the panel to the upper right of the circle would rack, causing bending of the overloaded upper chord. At the same time, the full weight of the tractor and bridge would be transferred to just one truss instead of two, effectively doubling the load on the remaining truss causing it to fail the same way, while also inducing a twisting motion. Progressive failure results, including in this instance, the bridge abutment, which was pulled toward the creek.

 

Thanks for that - you are correct on its location in the #1 and #3 image. The #2 image was taken on the opposite side towards the left and forward if you look at the #3 image. There were several that exhibited the plate separation.

a farm guy, just trying to get the work done, has to gamble with his life and lose on an old bridge. breaks your heart.

 

we really need an all out effort to improve infrastructure in this country. when we had the chance, i wish more of the meltdown bailout $ would have went to that kind of thing, like china did, instead of to the banks. china took advantage to invest in itself, unfortunately we did not or could not. i dont know whatthe answer is now, old bridges and the like arent going to fix themselves. ugh.

 

^Totally agree.  I had hoped that the bridge in Minneapolis a few years back would be the wake up call this country needed.  People were interested for a few weeks, then they forgot about it.  If that expressway bridge collapse isn't going to do it, I fear that nothing will.

^Totally agree.  I had hoped that the bridge in Minneapolis a few years back would be the wake up call this country needed.

 

Thirded. In Ohio the new I-71 bridge that replaces the Jeremiah Morrow bridge over the Little Miami is being rebuilt in direct response to the I-35 bridge collapse, because it used similar construction techniques and has similar age.

 

Government can't build or upgrade anything in this country today without being demonized as a left wing handout. The ideology from idiots has paralyzed us.

Not even left-wing handouts - there are some left-wing nutjobs here who only see it as a pet project for highway projects that should not have occurred. They point at it and call it frivolous spending for highways when it should all be spent on transit. One person on here even called the painting of bridges a waste of money - saying that it looked "fine" to him and that it was not needed as often.

 

All too often, we rely on our quick drive-by perspective for analysis, but it's our engineers and transportation officials who ultimately make the call because they are the most qualified. They understand how these bridges work, operate and ultimately deteriorate. For the I-71 Little Miami span, it is structurally and functionally deficient - and is fracture critical because of its construction type - its a deck truss. In addition, the gusset plates - like what was shown above, have been strengthened in various areas as they have weakened. The I-71 span is nearing its 50 year design life and either needs major structural rehabilitation or outright replacement. In the end, it was found to be more cost effective to do a replacement.

 

It's absolutely critical that these bridges be maintained or replaced as needed. It's stilly to think that some folks, who have no concept of engineering, want to pick and choose what our pet projects should be based on a particular ideology or political viewpoint.

When people look for egregious examples of deferred or neglected maintenance, they keep going back to the I-35 bridge collapse. If my memory is correct, the investigation showed that the collapse of that bridge was not caused by neglect or lack of maintenance, but by an engineering error; analysis of the stresses on the structure showed that the gusset plates should have been made from 1" steel plates, but the design called for 1/2" plates, and that's how it was built.

 

The bridge was in good condition and did not have corrosion problems; it failed because it was designed wrong and nobody caught the mistake before the bridge was built to the faulty design specs.

^Assuming that's true (and I'm sure that it is), diagnosing and repairing a design flaw is part of the maintenance that I hope would occur prior to catastrophic failure.  Finding out after the fact doesn't do much good.

^The Minnesota bridge apparently collapsed due to both a design flaw and extraordinary loading conditions during rehabilitation. The results of the design flaw, buckled gusset plates, were photographed in an inspection but nothing was done about it.

 

a farm guy, just trying to get the work done, has to gamble with his life and lose on an old bridge. breaks your heart.

 

we really need an all out effort to improve infrastructure in this country. when we had the chance, i wish more of the meltdown bailout $ would have went to that kind of thing, like china did, instead of to the banks. china took advantage to invest in itself, unfortunately we did not or could not. i dont know whatthe answer is now, old bridges and the like arent going to fix themselves. ugh.

 

 

This bridge was not part of the publicly maintained infrastructure system; so even with flush funding coffers this tragic accident would have still happened.

^ i know, it probably should have been inspected and closed. a shame.

We just tore out an old bridge at our farm because we were worried about this sort of thing. I'm glad we did it before something bad happened.