Clear Picture Analysis

I'm just a curious observer with no real knowledge of engineering or construction, but the first question that comes to mind is why this same technology has not been used to test (which I guess would be a hypothetical) bridges. Also, when it comes to human life how is a finding that a bridge is "deficient" acceptable under any circumstances? The word means "lacking some element or characteristic" (dictionary.com). So even if we assume that the bridge is functional, some "element" is still missing. Who decides what elements are superfluous? Apparently, in Minnesota the DOT does. I was appalled when I read the answer to why the bridge collapsed in this article http://minnesota.publicradio.org/display/web/2007/08/06/bridgetroubles/. Seems like there were many reasons to be wary already. Doesn't really seem like the reasons are such a big mystery based on the article. (And, yes, hindsight is 20/20.)

"Who decides what elements are superfluous?"

That word is abused. When ever I see that word "superfluous" is when it does not pertain to the person using it.

What may seem superfluous. May have a bearing on something you may not realize or understand. (which is a form of ignorance) which is something we all have.

And as far as safety or failure. tell me one thing manmade that is indestructible.

And then explain to me whats acceptable?

Follow by, who is going to pay for it?

When designing that bridge, one does not know what was involved or how it evolved. (engineering, bureaucracy, ect..)

It's not that I'm defending it, your questions about it are valid. It is just hindsight vision is 20/20.

And sometimes the best questions are asked by a party not familiar with it. Keeps us from becoming complacent.

dude, in exactly 144 words you made exactly 0 relevant points.

cr3

C Rummel3,

After looking my comment over, you were correct; I did dance around with examples and did not drive my point home. Thank you.

As TchrCreature was pointing out and coming to an obvious conclusion, as obvious as it may seem. My response to TchrCreature, one still have to try to keep an open mind, before coming to a premature conclusion, if for any thing missing a less than obvious short comings. Which may or may not have been to the design of, or specification callout, to inspection of that bridge, to who knows what else?

To fix or correct this from happening again. i.e., by learning everything one can from this disaster to keep it from happening again, by not coming to a premature conclusion.

Phoenix911

I am not certain of the inspection criteria of these products, the bridges. This is how they must be viewed, as manufactured products. They are most likely rated as to how they meet certain standards. I would assume that these criteria are sub-grouped as to a number of further rated factors, including: safety, accessibility, ability to meet future volume etc. Mind you I am just shooting off and do not know the exact criteria.

But the stated defficiencies might be paint, level of corrosion on railing, cracks in footings, road surface, striping, shoulder width or any thousand other determining factors, deemed relevant or noteworthy by the inspecting authority. So deficient is rather ambiguous at face value.

I am certain that something was overlooked or simply not recognized as structurally unsound or even just one of those things (we had an old building just fall down after standing for 200 yrs. Just gave up, and dropped).

Although this is an unfortunate accident, it is just that. An unforeseen, or unanticipated event resulting in an adverse outcome. We have tens of thousands of bridges in the US. They are not falling down about us. The matter is certainly worthy of all available resources in an effort to minimize, but alas a 0% failure rate just isn't possible. And unfortunately we can only hope to minimize the the impact of those failures.

please see... here or here.

cr3

"We have tens of thousands of bridges in the US. They are not falling down about us."

Actally they are. I-35W.

check this report http://www.fas.org/sgp/crs/homesec/RL34127.pdf

And I do not know the exact number of bridges it says about 600,000, but how are these many bridges being inspected and done throughly and competently in the time alloted.

Sure the man power to inspect is short, but are the bridges being inspected suffient and done thoroughly?

As far as the number of bridges, the majority of these bridges are rural and lower traffic bridges that belong to smaller towns, designed and constructed after WWII. with the materials and design techniques of the day.

And by todays standards will these bridges pass with the maintenence that is required?

Hardly, but they and are an integral part to the commerse of these areas.

Even though they are an integral part, is there money to repair them? no

Are there plans to repair them? for the majority of bridges, yes.

Can they be taken out of service until repairs are made? no

And what is being done to these bridges is putting load restrictions on them as a stop gap measure unto they can be repaired.

I believe there are allot of fingers being crossed until these bridges are brought up to a safe operating condition.

And the intent is take the bridge, building. tower or anything manmade out of service before its run into the ground.

Pheonix911,

Bridge Conditions Federal law requires states to periodically inspect public road bridges and to report these findings to the Federal Highway Administration (FHWA). This information permits FHWA to characterize the existing condition of a bridge compared with one newly built and to identify those that are deficient, either structurally or functionally.

A bridge is considered structurally deficient

if significant load-carrying elements are found to be in poor or worse condition due to deterioration and/or damage, or the adequacy of the waterway opening provided by the bridge is determined to be extremely insufficient to the point of causing intolerable traffic interruptions. A bridge classified as structurally deficient is not necessarily unsafe, but may requirethe posting of a vehicle weight restriction.

I don't know if you read the whole report, in it's entirety, fine print and all but there are a couple of points that support my previous statement taken from the report you posted the link to and I have include some, not all of those points above.

cr3

Sure these bridges are reported to FHWA, but what is the value of the reports, as to how throught how complete or thourgh.

If a bridge is deem unsafe and the report is passed along. that bridge is of course will be closed.

cr3,

We both basically agree, What was confusing when you replied to my earlier post.

"dude, in exactly 144 words you made exactly 0 relevant points."

Only to basically reinterate my earlier post with a different approach.

Thank you for being thourgh with your research though.

phoenix911

My pleasure, it's what I do.

From the television reports I saw it appeared (in some really good close ups) that corrosion was the culprit. The rust swollen pins which connected the bridge's moveable links to the supporting structure were shown sheared in graphic detail.

Anyone could see the rust in the pieces of broken links. The pieces of cracked metal had clearly visible rust stains marking the exteriors. Certainly the corrosion is at fault.

What I'm suspecting here is the deflection of culpability to the bridge designers and contractors, and away from the Highway Department and their clearly inferior "inspection" system As one Highway Department respondent, to a reporter's question, said "we look at it from over here ("here" being a quarter mile away) with binoculars".

I hate doing this........well not really.

"we look at it from over here ("here" being a quarter mile away) with binoculars".

That is typical. especally if its a government deployed rep. No matter what degree of importance. Because there is no accountablity.

An example though not as extreme or may not pertain to public safety. When I was on the farm we had the local people from what was called the ASCS office can't remember what it stood for "Agriculture and conservation service or something" . They look at our land to see how close the bedrock was to the surface for erosion control. They did that in the truck on the road, because it was raining, And guess what. they got it wrong. They were not held responsible, but their incompetent work also did'nt result in deaths.

With the bridge failure this is just one instance. remember that the next bridge you cross, or elevator you take, or ...... . Remember people that are there to reassure it's safe, are not doing their jobs. It may improve when they are held accountable, like the rest of us.

And yes it is not disappointing, it's disgusting.

As far as a designer, designing it to fail, I do not believe that happen intentionally.

But the techniques when it was designed, though using standard techniques, may not have been fully developed.

<Certainly the corrosion is at fault>

If one adopts the philosophy that accidents are caused, and don't just happen, then:

• Was the corroded material incorrectly selected?
• Was the corroded material overdue for replacement, repair or coating/protection?
• Was there a galvanically-enhanced rate of corrosion because of some other part that was incompatible with the corroded one?
• What changes were there in environmental conditions that enhanced the rate of corrosion compared with design?
• What other factors may have contributed to the enhanced corrosion of the failed part?

These are the sort of engineering questions that the legal profession might be seeking answers to in a public forum.

Excellent questions. I have always been somewhat fearful of things I can't control. I just started riding roller coasters six years ago. While I was able to avoid rides, I have not been able to avoid bridges. As remarkable in their technology as they are, I realize that a human being designed each bridge. Even a highly intelligent person cannot calculate the effects of the numerous variables that impact structures such as these over time. Nonetheless, I take it for granted that someone is watching (Big Brother?) and ensuring that my risk of making it safely to the other side is in my favor. Some people hold their breaths in tunnels. Maybe I'll have to start doing the same when I cross a bridge.