August 7, 2007

List Of Bridge Suspects Expands To Pigeons -- And Minnesotans

The inspections of the St. Anthony Bridge were difficult and dangerous affairs, according to a Star Tribune report. Spiders thrived on the support girders, and pigeons occupied the steel box sections where fatigue would have caused catastrophic failure. Those dangers don't compare, however, to the treatment inspectors got from passing drivers when lanes had to close to conduct the inspections:

Three experts familiar with the bridge said Monday that the impediments faced by inspectors included piles of pigeon guano, poor lighting, road rage and spider webs that could be mistaken for metal cracks.

A former MnDOT inspection supervisor told the Star Tribune that even the best inspectors had difficulty making a thorough evaluation of the I-35W bridge. Its sheer length, nearly 2,000 feet, was part of the problem, they said. ..

State traffic engineers would close lanes on the bridge for the inspections, and most of the time the lane closures were from 9 a.m. to 3 p.m. The snooper arms could operate from 10 a.m. to 2 p.m. That put inspectors under continual pressure to finish work before the evening rush hour, said one of three experts.

When the lanes were closed, it was not uncommon for inspectors to be the target of insults -- even thrown objects -- from inconvenienced motorists.

The length of the bridge and its position high over the water made it impossible to conduct inspections from below. The only possible way to complete them was to work as fast as possible for four hours straight, hanging over the edge while getting taunted and abused by the driving public. That's four hours for a 2,000-foot structure, of which 500 feet were over the Mississippi River.

One inspector called it a "balancing act of bridge safety and the driving public". Minnesotans should ask themselves why those two should be in opposition to each other. Those inspections were intended to keep those very people from falling into the river. It might be something to remember when driving over other bridges.

Pigeons may also have contributed to the collapse, and even bats as well. They nested in the junctions of the girders, and they left "piles" of guano on the very parts of the bridge that most concerned inspectors. The droppings both covered the areas where inspectors needed to check for fatigue and also corroded the metal over a long period of time. MnDOT tried installing screens to keep the pigeons out, but to no avail. The 2006 inspection report complained of "severe pigeon debris" in the box members.

Tim Pawlenty has already demanded a "stem to stern" re-evaluation of the bridge inspection process, which clearly is needed. We Minnesotans need to examine our own attitudes towards those who repair and maintain our roads and bridges. When we chase bridge inspectors away from their work, we shouldn't be surprised when structures fail later.

UPDATE: Earlier this morning, a friend sent me a series of photographs taken just after the St Anthony Bridge collapse. I've assembled them into a slideshow for easier viewing and hosted it at YouTube. These give a little more intimate look at the immediate aftermath -- and show some of the heroic rescue work that followed.


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Comments (19)

Posted by stackja1945 [TypeKey Profile Page] | August 7, 2007 7:17 AM

Or it could be written:
When we chase "protectors" away from their work, we shouldn't be surprised when the civil structures fail later.
Any public official stopped from performing their duties leaves the public open to such events.

Posted by mark | August 7, 2007 7:37 AM

Whining about bridge inspections and pigeons?

1) Do the inspections on the weekends.

2) 12 Gauges with 8 shot work well on pigeons.

3) Use a tennis racket on bats.

4) Tell PETA bridges are more important than pigeons and bats.

Posted by JeanneB | August 7, 2007 7:50 AM

I think you missed the larger irony (shame) in this article.

So now MnDOT is telling us how hard, if not impossible, it was to inspect the bridge. The pigeon guava alone insured that critical joints went uninspected.

BUT...wasn't it the same MnDOT that "chose" inspections over reinforcement? How are we to believe them now when they tell us they thought more frequent inspections would suffice?

Posted by deadrody | August 7, 2007 7:53 AM

Sounds like this and any other new bridge ought to be designed to facilitate these inspections. Think catwalk and permanent access platforms.

You have to weigh the security needs and the ability to keep out trespassers, but you shouldn't have to hange upside down from a manlift to perform critical safety inspections.

Posted by Lyle | August 7, 2007 7:55 AM

1. I read an interesting article published about a month ago in a professional civil engineering journal, which argues that visual inspections don't really work anyway, and that bridges must be actively monitored with electronic sensors.

2. re: natural environments. Civil engineers have great tools for modelling their structures under stress from wind, water, traffic, even earthquakes. But I don't think any of that software models the behavior of birds and the effects of piles of caustic poo.

3. stackja1945 makes an interesting point. It seems that every time I see an ambulance rushing somewhere with sirens sounding, I see some motorists who utterly fail to yield. People become incredibly self-important when they're behind the wheel.

Posted by athingortwo | August 7, 2007 8:15 AM

Captain Ed - how can I say this without seeming ungrateful for all the other highly interesting posts you usually deliver to your readers here on .... but, as to the I35 bridge story, ENOUGH ALREADY!

It's time for an intervention by your friends!

If your blog is to be nothing more than a local interest Twin Cities blog with an occasional mention of something from the outside world, just let us know ... and then most of us will stop visiting your blog. That unfortunate bridge's allotted 15 minutes of fame expired about 5 days ago.

Since the 13 or so people died in the bridge collapse that one day in the Twin Cities, an average of 120 Americans have died on the highways every single day since. And let it be said now, almost NOBODY - even in Minnesota - cares about the minutiae of bridge inspections, or the effects of pidgeon poop on structural steel.

Please, Captain, step away from the bridge story .... yes, there now .... careful .... ahhh, yes ... isn't that better now?

Are you ready to return to the real world, Cap'n?

Posted by Captain Ed | August 7, 2007 8:20 AM

Excuse me, but this is a pretty big story not just for my city but for the nation. If you don't want to read more about this story, skip to the 8 or 9 other topics I cover every day.

Sheesh. I'll send you a refund.

Posted by Greg | August 7, 2007 9:44 AM

I couldn't help noticing that some of the vehicles on the bridge and in the water had their airbags deployed. I wonder just how quickly someone can recover from the deployment of one or more airbags, and then how obstructed they'd be in exiting the vehicle?

Posted by sherlock | August 7, 2007 10:17 AM

Why not get the PR department at MnDOT to do the inspections... they not only seem to be willing to work overtime, but they seem to be incredibly creative in doing their job!

But if they don't have the training to do the inspections, then I guess we should just quit inspecting bridges - it is clearly just too difficult, what with them being way up in the air over and water and all. Why don't we build bridges on flat dry land where we can inspect them real easy? Maybe build a couple in the parking lot at the MnDOT. Just don't block any stalls, or people might give you nasty looks.

In case it isn't obvious, this whole Strib piece is a load of drivel - I think you need to find out which editor's kid is a junior manager there.

Posted by Laurence Sheldon | August 7, 2007 10:23 AM

I have driven a few miles. And I have observed a few things.

One of the things is that there is a regional character to a number of things in this story.

Minnesota is among the worst for rude drivers. The way they treat each other, road workers, and truckers it beyond description.

Nebraska (where i now live) is among the worst (maybe THE worst) for the deadly way (and maximally inconvenient when not deadly) in which road construction areas are maintained.

There are better ways.

Just last night as I was approaching an area where there were trucks (with all the flashing lights, spot lights and all) replacing a line of poles that had been destroyed earlier in the day in a storm) a car pulled out (to the wrong side of a rural road, on a blind hill, in the dark) to pass me because I had slowed because of the workmen on the road ahead. Fortunately the lights of a large truck blocking that side of the road persuaded the idiot to pull back in line.

And I suspect, but can't prove, let the text messaging go for a bit.

Posted by Enlightened | August 7, 2007 10:34 AM

Did anyone see Geraldo Rivera 2 nights ago? He was close to blowing a gasket over some what appeared to be x-ray pictures or some other type of picture of some of the joints on the bridge that looked like they were being held up with bricks or something? Geraldo made a claim that sometime this week he would be exposing the MNDOT for this failure? He was literally apoplectic in his denouncing the MNDOT.

I haven't seen a single thing close to his story on the MSM or anywhere else.? Just wondering if the MN local news agencies got wind of any of this?

Posted by Ari Tai | August 7, 2007 10:35 AM

My heart goes out to the victims and their relatives. May everyone who helped be helped themselves.

An aside. Another reason to privatize road ownership. What are inspectors doing working during the day on a busy overpass? Who's time is more valuable in the aggregate? If there was money in speed and efficiency and minimum disruption, the inspectors would be paid like surgeons and never see the light of day (or an irate motorist), and be happy about it..

Posted by athingortwo | August 7, 2007 11:20 AM

Cap'n - no "refund" is necessary (nice comeback, tho!) ... I was just trying a gentle little noodge away from seemingly all-bridge-all-the-time reporting by employing a small (non-existent?) touch of humor.

The national story of the I35 bridge failure, with tons of video, including the actual video of the bridge falling, and the inevitable human interest stuff, rescues, heroes, etc. was fine as far as it went ... but your decent into bird poo journalism was a sign that this story's been beaten to death more than any poor horse ever was.

Maybe it's because I live in Florida, and most of the time most Floridians get really sick of seeing the cable news networks going hog wild on one unbecoming Sunshine State story or another, til it's been thoroughly flogged to death. Local Florida stories gone national are neither unusual here, nor particularly welcome in most instances. After all, we've had the privilege of sharing our dirty underwear with the entire world, whether it was our damaged chads, or a Congressman with a penchant for pages. Not to mention those all-too-common stories of disastrous hurricanes. So I will allow that being from Minnesota, you might be tempted to bask as long as possible in the bright lights of 24-hour per day cable channel overexposure.

But with the war in Iraq at a turning point - along with the fate of our overall greater war with the Islamists ... and a wide-open Presidential campaign (for the first time since 1952) in full swing ... not to mention that another NFL season is about to start ... the startling news from the emerging science of pidgeon poo-ology, and the implications for the future of Minnesota bridge inspection doctrine, are pretty far down the lists of most people in most other parts of the USA..

But you're the Cap'n! No refunds demanded.

Posted by sherlock | August 7, 2007 12:57 PM

I hope it goes without saying that my sympathies go out to those who were involved in this tragedy.

With that disclaimer, I want to bring up something that may be considered distasteful. The Strib piece is an apologia pure and simple, and so much so that one has to wonder if my admittedly snide comment about what Strib Editor's kid is a MnDOT manager actually may have an ounce of truth in it....
does someone at the Strib have a conflict of interest re the MnDOT? Such reluctance to criticize does seem a bit out of character, doesn't it?

ps. I am not from Minnesota, and my information on this has been mostly from nationally-oriented coverage, so I may have a false impression of who has said what - which I would be happy to see corrected.

Posted by Conrad Wareham | August 7, 2007 1:22 PM

I think the paper also said that because of the threats to the inspectors the inspection reports were also going to be pulled from internet access. It seems to me that the state is expecting lawsuits so this story is a way of letting the public know that all inspection reports are now off limits to the public.

By the way, I appreciate you keeping this story going. There is much apathy out there concerning the deterioration of our public infrastructure.

It is ironic that the hardest places to inspect and the most likeky place the cracks would be is also the dirtiest? One would think that an effort would be made the clean these areas (perhaps steam cleaning) and a method for proper inspections would be developed. Where is our "can do" attitude?

And since when are we more corcerned about some idiots in the public complaining about inconvience than the public safety in general?

Posted by sestamibi | August 7, 2007 2:25 PM

Full refund for athingortwo. This story has national legs and should be followed. Furthermore, some of us are former Twin Cities residents (1972-80 in my case, plus MA University of Minnesota 1976) and still have ties to the area.

Posted by pk | August 7, 2007 4:27 PM

imagine doing this hanging a couple of hundred feet in the air.

1. sandblast clean the entire bottom of the bridge and all of the steelwork.

2. spray the whole thing with a thick dark red liquid being sure to cover quite thickly the entire sturcture.

3. leave it for about a half hour.

4. wash all of the red stuff off with a firehose (and listen to the complaints of "BLOOD" running down the side of the bridge and polluting the country side.

5. spray a white paint (called developer) over the whole thing. developer is bought in small (one pint) spray cans and tends to blow away from where you want it to land in any kind of breeze. one can will cover about a 4' square table in good conditions.

6. take out a mark 1 mod 0 eyeball and look for blood red cracks. do not be confused by "indications" which are not cracks but can be figments. eyeball everything and if you find something mark it and photograph it because rain washes the whole thing away. and if you don't have the camera and marker with you, you may not be able to find it when you come back.

ladies and gentlehomos, thats the way water washable dye penatrant crack detection is done. for this application it is about the most practical system there is. keep this in mind when you hear bigmouths advocate "testing".


Posted by poodlemom | August 7, 2007 9:39 PM

I think the issue is of interest and importance to many of us. Here in NEPa our local newspaper pointed out that we have 2 such bridges here in Wyoming Valley. One is considered fairly "new". It was built after Hurricane Agnes caused massive flooding in 1972.

Bridges that weren't washed away all needed massive repairs and some replacements. It's boggling my mind to realize the one bridge I thought I wouldn't have to worry about, is of the type spanning I35.

Posted by Niccolo | August 8, 2007 2:28 AM

With due respect to those who lost loved ones on the I35 bridge, I'd like to plant a meme in hopes some bridge engineer or engineers read it and take off with the idea:

Bridges should be designed or retrofitted with service-vehicle areas on each approach. The sides of the bridge should have trolley rails built in such that an articulated service/inspection trolley capable of reaching every part of the bridge can be offloaded from its transport vehicle and hung onto the rails on the bridge without impeding traffic. This system should be uniform for every bridge within a (fairly large) jurisdiction.

The cleaning crew goes first with pressure-washing equipment, blasting off any bird- or bat-guano, and any rust or paint flakes. After suitable drying time, the inspection crew can come through.

If all is well, or remedial actions are completed, the trolley is loaded back on its transport vehicle and goes to the next bridge.

So there it is. Newer bridges could have it designed in. Older bridges could often have the rails added. No traffic problems. Anybody who reads this and wants to take the idea and run with it, Godspeed.

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