Friday, August 03, 2007

How Indiana Bridges Fare

About 25% of Indiana bridges are considered "structurally deficient" or "functionally obsolete" according to the U.S. Department of Transportation. By comparison, Minnesota reported 13% of its bridges fell into one of these categories, including the I-35W Bridge over the Mississippi River, which collapsed on Wednesday killing dozens. I'm bothered by how transportation engineers can't agree on the meaning of these designations. As INDOT explains to the Star:

But Indiana Department of Transportation officials on Thursday called those terms misleading, arguing that they signal only a need for repairs or an update of bridge design, not a breakdown in the safety of the bridge.

"These are engineering terms, and they sound a lot more severe than they are," said INDOT spokeswoman Megan Tsai. " 'Structurally deficient' could be the paint on the beams was chipping."

A Purdue engineering expert totally disagrees with INDOT on this point. If it's 'structurally deficient,' then that's a serious problem," Kumares Sinha said. "I would consider it a serious matter, not just paint peeling off or something." "In classifying a bridge 'structurally deficient,' inspectors might identify a crack in a bridge's steel structure, or significant deflection -- bending -- of the bridge's deck when a vehicle drives across it, Sinha said. Those are serious problems, he said.

I suspect Sinha is more right than INDOT on this one. I had the pleasure a few years ago of working with a very distinguished retired engineer from INDOT who shared with me potential disasters all over the place. He warned me pre-Katrina there would be a massive failing of the levy systems in New Orleans. He talked about Indianapolis' crumbling sewer system. How many times have you witnessed a cave-in of a public street occurring before a city sewer has gotten fixed? He talked about how the city's water pressure is so inadequate in many locations around the city that IFD would be unable to fight a major fire. As I recall, that's exactly what happened when a skating rink caught fire a few years back. Firefighters lacked enough water pressure to fight the fire so the building just burned. And yes, he complained about the state of many of our bridges around the state and across the country. So the answer to the question can like what occurred in Minneapolis this week happen here? Absolutely.


Anonymous said...

Infrastructure repair isn't "sexy" as a political issue. Who would fondly remember the Bart Peterson Memorial Storm Sewer Project? Nowhere to put up cool plaques with the names of all the cronies who helped spend their way through the rest of our inheritances?

Worse, it costs quite a bit of money, which currently isn't a popular subject.

Mike Kole said...

I think it will become a popular subject now.

During my time at the Hamilton County Surveyor's Office, I reviewed bridge plans coming out from the HC Engineering Dept. Hamilton County has been very aggressive about replacing bridges in the past 10-15 years, and yet, a good number are very deficient. I was reviewing no less than 10 per year, which represents a lot of money. But in light of the fact that there are more than 300 bridges in HC, and then more than 100 more "small structures" that aren't long enough to technically be classified as bridges, you start to see that this can be a major, major expense for any county's taxpayers, but a necessary one.

To the county's credit, there is a schedule for replacement in place. But bridges aren't cheap, so they are rated and then tackled in order. It's a very rational and sensible way of doing things, but I think that even in an aggressive county like Hamilton, many would be shocked at the condition of some of the older bridges they may pass over every day, never thinking about it- until now.

I think this incident will help focus attention in other counties that may not be so proactive or aggressive about replacing or repairing deficient structures- not just bridges, but also culverts.

Wilson46201 said...

Bridges aren't painted to make them look pretty but to protect from corrosion. Paint chipping is merely a sign of incipient problems of rust and decay...

Anonymous said...

Wow, not only Wilson an expert when it comes to politcal matters, now he offers words of wisdom on bridge engineering. How does he find time to be an expert on so many things, I mean with all the time he spends on blogs, how does he do it????

Anonymous said...

I wouldn't know either way. It does seem like anymore people treat big bridges as pieces of art or architectural wonder instead of a means to an end destination.

Hopefully everybody will learn from this and move forward.

Wolfrham Hart said...

A friend of mine who is an Purdue trained engineer explained his opinion of what most likely happened (a major structural joint connected to a pier failed) and how bridge inspections are performed. My friend admits he wasn't a structures engineer, but his firm did perform bridge inspections.

1. Bridge inspections are as much art as they are science. The art part comes into play with parts that aren't visibile. Performing an inspection is very hard, especially when the structure is 60 feet above water.

2. Bridges are engineered and the inspections are set up to be very conservative. Given that you can't see all the critcal parts conservative seems like a good idea.

3. Despite conservative engineering and inspections that err on the side of caution the system isn't foolproof as noted by this incident.

4. Any phrase such as "structurally deficient" doesn't mean a bridge is going collapse tomorrow. The terms in bridge inspection reports are
specialized to that field. The connotations and meanings can be
subtly different from their use in everyday life. [My opinion the PR flack from INDOT took things too far by saying it could only mean the paint is flaking, but the flack's basic concept is correct.]

And now for some final thoughts: if you watch the History Channel or Discovery Channel often they always have a show about great engineering disasters. While the events in the Twin Cities was tragic, bridges, buildings, airplanes, ships, and other infrastructure failures aren't uncommon. It's the risk we take to live in our mechanized, urbanized world. We hope the things our society depends on are built, maintained, and replaced properly, but sometimes they aren't. Even when they are that isn't a guarantee that all goes well.

Anonymous said...

"I'm bothered by how transportation engineers can't agree on the meaning of these designations."

You mean, the way lawyers always agree on the meaning of laws?

As someone who works with both engineers and lawyers but is neither herself, it never ceases to amaze me how little understanding each profession has for the other.

Anonymous said...

"Bridges aren't painted to make them look pretty but to protect from corrosion. Paint chipping is merely a sign of incipient problems of rust and decay..."

All this from someone who claims he doesn't know how to drive.

garyj said...

"Wow, not only Wilson an expert when it comes to politcal matters, now he offers words of wisdom on bridge engineering."

I am not a fan of Wilson by any means, but in this case he is dead on. (yes, it pains me to say that Wilson is right about something)

The elements, (rain,snow, sun, etc..) along with road salt and the acids that linger in the air from exhaust, combined with oxygen, cause corrosion. Painting protects the metal and wood from the aforementioned items.
While these bridges could be painted a lot more appealing to the eye, it does cost money to do so.
The paint is also sepcially desigend to withstand the elements for a specified time. Ugly but effective

garyj said...

And once again, I prove that I can't type!

Wilson46201 said...

Sadly, an anonymous nobody seems more interested again in discussing me than the thread topic. Am I so much more important than war or bridge collapse? Why do they try so hard to disrupt this Blog?

Anonymous said...

I don't think that garyj is anonymous, Wilson. He post under his name, just like you! Even on indyu, TDW, and here. Looks like he even agreed with you.
Can't you just say "thanks" and let it go?
Man, you relly need to get a clue on life

Wilson46201 said...

I wasnt referring to Gary Jennings but the anonymous nobodies at 8:28am and also at 2:52pm ... they seemed more interested in disrupting this Blog.

Anonymous said...

Come see what the railroad bridges look like in Gary , Indiana and see
The video of them.

It is time for the legislature to step in!

IDOT is passing the buck instead of removing dangerous structures tha cross state highways.

Anonymous said...

Pease come view the topic of bridges here @