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Posted by mr williams (Member # 1928) on :
 
The news reports say that part of the bridge collapsed onto a freight train - anybody have any more details? Was it parked up or moving, and what was it carrying? Thankfully, it seems that the cargo must have been non-flammable or it could have been an even worse disaster.

Is this the same rail route as taken by the Empire Builder?
 
Posted by TwinStarRocket (Member # 2142) on :
 
The freight train under the bridge was on dead end track, that used to be the feeder into the Great Northern Passenger Station. It was very likely those train cars had been sitting on the tracks for weeks.

These tracks led to the famous Stone Arch Bridge built by James J. Hill, known as the "Empire Builder" for whom the train is named. Built strictly as a way for passenger trains to get into downtown, this winding s-curved bridge over the Mississippi is said to be so strong and well-built that it is nearly indestructable.

Now it is a beautiful pedestrian overlook of St. Anthony Falls and the locks, and it is an attraction I highly recommend for visitors to Minneapolis.

The Empire Builder runs parallel to these tracks about a mile away, and has not gone through downtown Minneapolis since Amtrak moved to a station midway between the Twin Cities.

There are always quite a few pedestrians and bikers (including me) enjoying the river who pass underneath the bridge that is now collapsed. I hope there were none unfortunate enough to be there last night.
 
Posted by RRRICH (Member # 1418) on :
 
The news media said this was NOT a terrorist attack, but I am not so sure about that.........

Citizens reportedly heard some distinct "explosions" before the bridge collapsed, and it collapsed in 4 specific places -- very well could have been bombs, couldn't it have? I know there are no earthquakes in Minnesota......

What is the feeling up there, Mr. Twin Star?

For George H - news media says the bridge had a "structural collapse." Is this possible?
 
Posted by train lady (Member # 3920) on :
 
Rich, they also said that there was a work crew of 24 repairing the bridge so there are a number of possibilities. Don't you think if it were a terrorist deed the responsible group would have made a claim? Frankly I don't think it serves any useful purpose to speculate, Here in the DC area we are so attuned to terrorist possibilities thatis the first thing people think about. We have been sent notices by the local gov't and the red cross to prepare for emergencies, supplies to have on hand and how to evacuate the area or shelter in place etc. I assume there are other places doing te same. So lets just wait and see.
 
Posted by TwinStarRocket (Member # 2142) on :
 
The repair work on the bridge was surface work and not structural. Lanes were closed and traffic was funneled into a smaller area.

They ruled out terrorism quite early, but an investigation will probably take months to determine the cause. As for explosions, citizens also reported seeing pedestrians and bicycles fall off the bridge. It's a freeway bridge. No pedestrians and bicycles allowed. They take the parallel bridge, built to last in the '20s.

Minnesota did have a very slight earthquake in the 80's but they would never be strong enough to take a bridge down.

On another thread (Grandluxe & booze)I mentioned there was a same day article before the collapse about the next bridge downstream, built at the same time, being judged unsafe for light rail.
 
Posted by RussM (Member # 3627) on :
 
The same thing happened in Connecticut in 1983, when the Mianus River Bridge on I-95 collapsed. Cause was determined to be poor design, and lack of maintainence. CT embarked on a major program to beef up just about every bridge in the state.
 
Posted by bmpbmp (Member # 4537) on :
 
If it was a terrorist act, which I really, really don't think it is, it hasn't created terror.

I appreciate the info above concerning where the Empire Builder goes thru twin cities - I've been curious if it passed under that bridge.

I've heard it collapsed on a rail car that had "chemical beads", but exposure wasn't deemed risky.
 
Posted by 20th Century (Member # 2196) on :
 
Well TwinStar, happy to hear that you weren't biking under that bridge. I knew you would offer some detailed info of the area around the bridge. Thanks. I seem to think that it was the bridge's design which was the problem. But time will tell. I'm no expert on it. I read a brief explanation about the design on internet news.
I myself have a problem transversing some bridges. everytime I travel to Long Island, NY to visit family I hope traffic is not stopped on the Verrazano-Narrows bridge which connects Staten Island and Brooklyn. If they still had ferry service between Staten Island and Brooklyn I would use it instead of crossing that bridge. Of course direct Amtrak service to Long Island would be a fantasy come true.
 
Posted by Gilbert B Norman (Member # 1541) on :
 
This is not the first of such incidents; a thought with which I'm certain Mr. Harris will concur, is that our infrastructure is simply "worn out".

I was "out there" visiting family when this incident noted earlier by RussM occurred during 1983:

http://www.ntsb.gov/publictn/1984/HAR8403.htm
 
Posted by Mike Smith (Member # 447) on :
 
I saw a video of the bridge collapse. It appeared the structure failed at one of the supports and took the other support and bridge with it.

I've seen wrought iron being held in place by the numerous layers of paint Perhaps they will find the interior of those rectangular structure members had rusted from the inside-out.
 
Posted by TwinStarRocket (Member # 2142) on :
 
For those interested, more info on the Minneapolis Stone Arch Bridge, built in 1883 and used by the Empire Builder until about 1978.

http://www.mrdbridges.com/stoneArch.php

This bridge is just upstream of the I-35W collapse, and will probably outlast its replacement.
 
Posted by George Harris (Member # 2077) on :
 
Sometime between six months and a year from now there should be a fairly exhaustive report from the NTSB on this collapse. Until then you can regard what is said about this collapse as guesswork. (The level of certainty in most early comments is usually inversely proportioned to the level ofknowledge behind the comment.) I am not about to make any guesses in public because 1. I don't know enough about what happend to comment, and 2. If that was not enough, it has been "strongly suggested" by our management that if asked to comment about this subject in public to refrain from doing so.
 
Posted by Gilbert B Norman (Member # 1541) on :
 
quote:
Originally posted by bmpbmp:
I've heard it collapsed on a rail car that had "chemical beads", but exposure wasn't deemed risky.

Looks like ExxonMobil is out one covered hopper(scroll "Page Down" seven times):

http://hotair.com/archives/2007/08/01/breaking-horrific-bridge-collapse-in-minneapolis/
 
Posted by musicfan (Member # 4673) on :
 
Along with the majority of regional residents, I used this bridge several times each week, so it is a strange feeling to say the least to hear of this collapse.
Many times while driving over this bridge I would sneak a look over my shoulder to the view of the stone arch bridge lighted up at night and the beautiful view of downtown Minneapolis.
Just the other week I went to the Guthrie theater to a play nearby to this bridge, and watched the aquatennial fireworks over the river.
I think I heard it averaged around 140,000 cars a day, so it will certainly be difficult to replace in the short term.
I saw in the paper before all of this, that the highway bridge they were planning on using for the new light-rail central corridor line to St. Paul was not able support the additional weight and would have to be fixed up.
That is a short distance downriver from this one.
It perhaps would be impossible to combine the two projects, but I hope they at least are aware of each other and get either one or both bridges built or rebuilt as quickly as possible.
It's predictable, but I think it is disingenous for people to immediately cry for more taxes and spending and claim all the infrastructure in the country is going to H in an H basket.
Infrastructure is important, but it is also a special interest of people just like education or health care or the environment or defense.
It's like claiming you need a cop on every street-corner every time there is a murder or crime.
Public Policy is full of compromises.
Everyone in education claims their issue deserves the most money because it's "for the children", people in health care say our natural health is the most important thing in the world.
Defense claim national security, crime and punishment, claim police and jails.
Somewhere the right balance must be struck, but acting like we can replace every bridge in the country right now is not a plausible notion.
Does the infrastructure need fixing?
Of course.
Can you prevent all possible accidents by spending money and having the latest designs?
NO!
I'm reminded of the Bible passage where Jesus asked rhetorically "Or those eighteen on whom the tower in Siloam fell and killed them,.(A bible times news story).
Do you think that they were worse sinners(or more guilty) than all other men who dwelt in Jerusalem?
I tell you, no; but unless you repent you will all likewise perish.”

My personal interpratation being that Accidents happen, and take care of your own personal and spiritual situation because you don't know the when's and the why's of future events.
 
Posted by sojourner (Member # 3134) on :
 
I am sorry to hear about this happening, and glad you are well, Twin Star. And you too, Music Fan; didn't know you lived in the area.

Have they looked into the possibility of the fireworks damaging the bridge?
 
Posted by Gilbert B Norman (Member # 1541) on :
 
quote:
Originally posted by TwinStarRocket:
For those interested, more info on the Minneapolis Stone Arch Bridge,...and will probably outlast its (I-35) replacement.

Lest we forget, Mr. TwinStar, the 1965 floods did a pretty good job on Stone Arch.
 
Posted by Kiernan (Member # 3828) on :
 
Highway bridges are inspected every other year, at a minimum. Even the small low-traffic-volume bridges that we have on the Santa Fe National Forest are inspected every other year. What happened to the people on the bridge is terrible, but I also worry about the people who inspected the bridge last time.

It is quite likely that witnesses heard "explosions." When a structure like that fails, the sounds of the pieces coming apart can seem to be explosions.

This is a problem of money. You can solve problems by throwing money at them, the Defense Department does it all the time. It is way past time for us to increase taxes to pay for the infrastructure problems that we have in this country. We have roads and bridges and airports and railroads and ocean ports that we have to fix. You can't have an economy and society like ours without transportation.
 
Posted by notelvis (Member # 3071) on :
 
I'm feeling a bit of relief.....my wife and I between us have several old friends living in the Twin Cities. They also have responded that they are well.

One friend has a daughter who is an ER nurse at what I presume is the University of Minnesota Hospital....close enough that those who could walk away from it walked in for medical care. Another friend knows someone who was driving on one of the sections that fell flat for only 30-40 feet and walked away unhurt.

Simply devestating to watch the pictures and realize that many were not so fortunate/
 
Posted by Mike Smith (Member # 447) on :
 
In 1993, Congress added 4.25 cents onto the gas tax and dumped every bit of that into their general fund. What Congress could do is take that tax money and put it back into transportation, like 2.25 cents for bridge repair and 2 cents for passenger rail.

I'm writing my Congress Critters.
 
Posted by notelvis (Member # 3071) on :
 
The following article in Trains Newswire might be of interest regarding the destroyed rail cars.
 
Posted by Tanner929 (Member # 3720) on :
 
the ny papers and tv are in the can it happen here modes with pictures of the blooklyn bridge. as in past discussions about the hudson river tunnels and bostons big dig odds are the brooklyn bridge will be standing far longer then some of todays modern marvels.
 
Posted by TwinStarRocket (Member # 2142) on :
 
Minnesota's Governor Pawlenty has vetoed most transportation infrastructure funding bills passed by the legislature, because of his no-new-taxes pledge. Even this year's 5 cent increase in the gas tax, which hasn't increased in over a decade, was vetoed. As a result, many schedules for replacement and maintenance have been been lengthened due to lack of funding.

He appointed his Lt. Governor Molnau to double as Transportation Commissioner. She was an infamous anti-rail legislator, who called the Minneapolis Hiawatha Light Rail line the "train to nowhere", and still opposes all rail projects.

Previous Gov. Jesse Ventura (a rail advocate) had a very qualified full time Transportation Commissioner, who strongly supported new rail projects and accelerated bridge replacement, and opposed reductions in staff and outsourcing of inspections.

Republican Pawlenty won both times with vote percentages in the 40's due to third party candidates running. His budget cuts have resulted in many lawn signs going up in the Twin City area that say "Willing to Pay for a Better Minnesota".

Gov. Pawlenty reversed his original opposition to the Northstar Commuter Rail Line (on the Empire Builder route to St. Cloud), which primarily will serve a heavily Republican district and is very popular with gridlock-weary voters he needs.

This is not to say the tragedy that just occurred is the direct result of political policy. But like we may feel about Amtrak, it is cheaper to invest in transportation now than to let the situation get so bad that we spend even more money to get out of a high profile crisis. The same politicians who saved our hard earned money from wasteful government spending will now show us they can demonstrate leadership by spending even more money in reaction to an event that maybe could have been avoided. It makes one long for the days when politics had visionaries like Jesse "the Bod" Ventura.
 
Posted by train lady (Member # 3920) on :
 
Well Tanner, I certainly support freedom of the press as necessary in a democracy. BUT it seems to me that whenever there is a crisis the media grab on like a *** with a bone and won'tlet go. They go on ad nauseum with the same pictures and facts which in some cases are few. Then they seem to go into their would, could, should, what if, and "we have heard from our sources unconfirmed reports that..." modes. There must be a better way.
 
Posted by train lady (Member # 3920) on :
 
Addenda, Regardless of political party we hear "the white house, the pentagon etc says" " we have the situation uner advisement etc." I think DC must be the only city where the buildings talk to each other.
 
Posted by musicfan (Member # 4673) on :
 
Disappointed Twinstar that you would stoop to such political invective.
This accident had absolutely nothing to do with the Governor's political policies whether they are right or wrong and it is a cheap shot and cheap political point scoring to try to assign blame to him or his appointees,I'm not surprised, but discouraged that leaders or members of any party would try to turn these heart-wrenching images into votes.
The inspections showed the same thing when Governor Ventura was in office for heaven sake.
This bridge would not have been replaced whoever was in the Governor's office from whatever party, or if they had a gas tax of five dollars. It was not recommended to be replaced for at least 20 more years.
Besides just being an accident, if any failure occurred it was in the inability of bridge inspectors to differentiate and bring attention to serious safety concerns apart from that of regular issues that need to be addressed but don't have a safety component.
These inspections and their recommendations are carried out outside the political process by bridge engineers.
The bridge was inspected more than often enough, so there is something wrong in the process, either the inspection must be conducted in a new way in order to catch a safety issue and highlight it, or if the inspections themselves are fine, to find new words and form to properly describe an actual structural safety issue in lay-mans terms apart from ratings that also include factors like "we need a new lane, signs, resurfacing, paint or guardrails",
If a bridge report showed a potential for actual collapse, it should actually use those terms in any report to the Governor, not minutia like "fatigue cracking not likely in deck truss, but stress in the structure ya da ya da ya da"
It sounds like the last time they had a chance to avoid the accident was that MNDOT was given an option to add some steel reinforcement plates earlier this year or late last and decided instead to proceed with more detailed inspections to determine where to put them.
Obviously this was an grave error.
But this all has nothing to do with funding or politics.
If somebody would have told the Governor or any governor that the bridge was unsafe, he would have shut it down in about five minutes.
In order for a Governor to listen to advice like that, you cannot "cry wolf" every week and claim that 50% of the state's or countries bridges are in trouble and need huge amounts of spending to fix them. If you do that, it will just sound like an agency trying to get their share of the budget, which is what they all do every year.
And properly, each agency makes the best case for their projects and funding, then compromises are made in order to make it fit.
But this bridge was different, it needed to be fixed quickly or shut down
It sounds to me like this could have been fixed very cheaply with a little steel reinforcement, but as is typical for Transportation people, they decide to "study" it some more and wait for the perfect all encompassing insanely expensive solution how ever many years or decades in the future to come about, instead of just providing a quick solution to actually fix the problem in the short term.

Incidentally, I was in Minneapolis last evening and it went pretty well driving wise coming from 35W North, I first took 280 to University and got something to eat in Dinkytown at the "Loring Pasta Bar.
http://www.loringpastabar.com
Very cool place!! totally awesome architecture and atmosphere.Probably one of the most interesting places in the Twin Cities to eat. The pictures don't do it justice.
I thought the food was good, although I'm not a real connoisseur and don't drink wine or any alcohol so I can't give detailed recommendations on that score.
Then I went over and took the Hennepin avenue bridge downtown and saw a great band.
Coming back home I took the recommended route of I-94 to 280 back to 35W North.
They blocked off certain exits and made the traffic lights stay green to turn 280 into a freeway, which worked well.
I think drivers in the Twin cities will primarily lose a little time, but little else due to the bridge collapse if they were not directly affected by the tragedy.
Too bad we don't have the central corridor light-rail up and running,
That would have helped mitigate the traffic problems.
Respectfully
 
Posted by Mike Smith (Member # 447) on :
 
Every year, when we arrive into St Louis from the south, the Eagle passes under this bridge, just before entering the station.
 -


Here's a picture of a school bus passing over that very same bridge.

 -

I wonder just how bad the collapsed bridge was?
 
Posted by Mike Smith (Member # 447) on :
 
quote:
Originally posted by train lady:
Well Tanner, I certainly support freedom of the press as necessary in a democracy. BUT it seems to me that whenever there is a crisis the media grab on like a *** with a bone and won'tlet go. They go on ad nauseum with the same pictures and facts which in some cases are few. Then they seem to go into their would, could, should, what if, and "we have heard from our sources unconfirmed reports that..." modes. There must be a better way.

There is a better way. However, the "media" MUST quit hiring journalists and start hiring reporters. Instead of trying to be the National Enquirer or Entertainment Tonight, the media should start reporting the news and have some intelligent people on the payroll. Right now, the "media" employees are way more interested in producing an entertainment program, instead of a news program. {Please note: Fox was NOT excluded!}

We get what we expect from our "media". Fortunately, we all have access to the internet!
 
Posted by Gilbert B Norman (Member # 1541) on :
 
Mr. Smith, I find that 'journalist" is the term those within the profession desire to be called.

I've been called it before, but I do prefer CPA to "Tax Man' or 'Bookkeeper'.

I believe your term entertainer regretably all too often is "right on'. Would O'Reilly and Hannity have their ratings if they treated their hostages with a little decency and respect?

I further understand that in some demographic groups, infotainment shows such as Jon Stewart and "the News" outrate the likes of Katie, Brian, and Chuck.

Further, I'm starting to learn that the world at large's day does not stop when network evening news comes on (I don't think Fox Brodcast even offers it) as has mine for the past 40 or so years.
 
Posted by Mike Smith (Member # 447) on :
 
Mr. Norman:
If the main stream media employed real reporters, we would have no need for Hannity or O'Reilly. They would not have anything to talk about.

Journalism has devolved into the dumbest profession on this planet. They do not need common sense, logic, analytical abilities or even facts. All they need is emotional impact.

A modern-day journalist would have to be shown which end of the shovel to use. The warnings you see on all ladders were put there because journalists couldn't figure out how to safely use one.

And the major networks still have their evening news shows??? Who knew...
 
Posted by train lady (Member # 3920) on :
 
Mike while I agree with you on the entertainment notion I must say I don't find the internet any better. I read as many different explanations of the new "free drinks" bit on the net as I have heard on TV. It gets to the point where it is hard to know what is for real. Then you add the politicians slants and it gets to "whatever"
 
Posted by Mr. Toy (Member # 311) on :
 
I've thus far refrained from getting into this topic because it really opens up a can of worms for me. I see the collapse as merely one of many symptoms of an ailing nation that seems more interested in cosmetic problems than structural ones.

I've been hearing for 20 years that America's bridges were deteriorating. But it was always back-page news. It doesn't get anyone's attention until a bridge actually falls down.

Instead politicians and reporters go into ecstacies over O.J, Elian, Monica, Princess Diana, Gary Condit, Terry Schiavo, Paris, Brittany, etc. all while bridges are rusting and levees are eroding. For years there were warnings that New Orleans couldn't withstand a major hurricane, but nobody who could do anything about it paid any attention. And I notice the public went right along for the ride.

What is Gary Hart best known for? Monkey business. Hardly anyone even knows, much less cares, that he and Warren Rudman headed a commission that warned of potential terrorist attacks two years before 9/11. About that same time security people at the World Trade Center even predicted that the next attack on that landmark would probably be by air, yet nobody paid attention.

We as a nation just aren't focusing on things that matter. We boast about how great America is, while we let it crumble around us. Only when something crumbles spectacularly enough to make TV news does anyone notice. Then we vow "never again," for awhile anyway, then we go back to fussing over Paris, Brittany, etc.

At this rate our favorite subject, Amtrak, won't get noticed until the NEC slides onto the sea.
 
Posted by Mike Smith (Member # 447) on :
 
In other words, Mr. Toy, you are stating that the USA is following the same path that Rome followed in it's latter days.

I tend to agree.
 
Posted by notelvis (Member # 3071) on :
 
I nominate Mr. Toy's entry for

'Post of the Year'

After a successful email and telephone campaign accomplishes my stated objective, I will then make the time to schedule an appointment for that physical exam I've been putting off and maybe even have the brakes checked on my vehicle.

And that's the way we do it I'm afraid.
 
Posted by train lady (Member # 3920) on :
 
Thank you for saying what I have been muttering for many a long year. We are watching the decline and fall of the American empire. I couldn't care less about the poor stars and athlete who make millions and have drug problems. I care that we always find the money to help other nations, fight wars,give all sorts of services to illegals but never have enough to fix our infrastructure, fund a decent rail system, help our own citizens ( and legal immigrants). Oh yes Congress seems to find the funds for their own perks and pet projects like the bridge to no where in Alaska. Think of what some of that misused money could do if it were used for Amtrak!! Now I shall get off my soap box.
 
Posted by TwinStarRocket (Member # 2142) on :
 
Posted by Mike Smith:
"In other words, Mr. Toy, you are stating that the USA is following the same path that Rome followed in it's latter days."

And on the cutting edge of our march down that path is our passenger rail system.
 
Posted by zephyr (Member # 1651) on :
 
The sky is falling. The sky is falling.
 
Posted by Gilbert B Norman (Member # 1541) on :
 
After reviewing this material appearing in Today's New York 'Mini' Times (today they adopted the 12" width format of most other papers), I am lead to wonder to what extent it is possible to estimate the load on a highway bridge at any given time?

http://www.nytimes.com/2007/08/06/us/06collapse.html

Railroads are not confronted with this problem, as the weight of any train is known. Railroads can and do restrict the weight of trains on bridges. Case in point is the Kate Shelly Bridge in Central Iowa where even though double tracked, only one train may be on the bridge at any time.

Of course, for those around here who contend that UP is letting their property "go to rack and ruin', it should be noted September TRAINS has an article stating how this bridger is being rebuilt so that two trains can be accomodated simultaneously.

http://www.hdrinc.com/Assets/documents/Publications/RailLine/june2007/KateShelley.pdf
 
Posted by train lady (Member # 3920) on :
 
well Zephyr, just make sure you are not under it when it does.I'd hate to lose a valuable member of the forum.
 
Posted by train lady (Member # 3920) on :
 
Since I am clueless to the structuring of bridges could one of our civil engineers answer a question? What other factors other than weight can cause a collapse? Would there be a situation where weight had nothing to do with the problem? On crossing the Mississippi on the Zephyr I am always a little uneasy,especially when I look down and see nothing but water.
 
Posted by George Harris (Member # 2077) on :
 
Train Lady:

You are asking a question that would take a long time to give a good answer to. However, for your part 2 worry: Relax. First there is nothing that gets the care and concern on a good railroad line line a major bridge, even if it looks bad. Second, a passenger train is far lighter both per axle and in total than a freight train, so if the freight train before made it across, you will too.

George
 
Posted by Kiernan (Member # 3828) on :
 
Since I'm a registered professional civil engineer in two states, I'll try to answer Train Lady's question.

Lots of things can cause a bridge to collapse. We've all seen film of the Tacoma Narrows Bridge--sometimes called Galloping Gertie--as it failed in wind. No weight at all on the bridge. Certainly an earthquake could make a bridge come down, as happened in the East Bay during the Loma Prieta earthquake, which also took down the bell tower at my high school. What happened in Minnesota was probably the failure of some specific component on the bridge. That bridge was designed in the B.C. years--Before Computers. It's quite simple now to make a computer model of a bridge and allow the computer to simulate component failure. And then modify the design.

The Minnesota bridge was a steel arch. Arches are common bridge structures, the Roman aquaduct bridges were built with arches. The Roman bridges, though, used stone or masonry for their arches, an ideal material. Steel arches are generally made from pieces that are connected together, usually with rivets or high-strength steel bolts. These bolts or rivets can fail, particularly when the road maintenance crews use salt in the winter.

For these reasons, bridges have to be inspected carefully. Federal law requires inspections every other year. Many years ago, my first civil engineering job was as a bridge inspector. Inspectors now take a two week training class and regular update classes. I don't do that kind of work any longer, but my office mate does and he's off to Seattle next month for his refresher class. I guess it would take weeks to inspect a bridge like the one that collapsed.

Scoll up in this thread and look at the picture that Mike Smith posted of the St. Louis bridge. The white stuff that hangs down is call "efflouresence." I think I got the spelling right. It's a sign of concrete deterioration, and huge chuncks of the concrete have fallen off exposing the reinforcing steel, which is hanging down. The steel carries the tension load in the reinforced concrete, but to carry the load it needs to be bound to the concrete. Which it is not in that picture. If that bridge was to fail, would it be "weight" or bad maintenance? When I was riding the Acela from D.C. up to Stamford, CT, a few weeks ago, I saw lots of bridge like that, and I wondered how are we going to pay for that.

Generally, bridges are quite safe. Transportation management, though, needs to listen to the inspectors and act on the recommendations.

Sometimes the way a bridge acts can be deceptive. I remember being stopped in traffic on the Interstate 10 bridge in Baton Rouge and feeling the bridge bounce under the deflection caused by the eighteen-wheelers. Bridges deflect and it's perfectly normal.

It is creepy, though, to look out the window and see the water when you're crossing the river.
 
Posted by George Harris (Member # 2077) on :
 
Kiernan:
Are you sure it was an Arch? My impression was that is was a Cantilever, just by having the roadway on top was essentially upside down from the normal steel truss cantilever arrangment. You are the former bridge inspector, so I could well be wrong, but it sure did not look arch like to me.

Also in could well be in the early days of computer use in design. I began my engineering education in 1962, and we did have one course in the curriculum on computer (an IBM 1620. I may not remember the model of my first PC, but that I will not forget.) in which we actually got to be in the presence of the computer for a couple of classes. It was treated about like entering a temple and approaching the idol, only lacking the burning of incense to make it complete.
George
(currently PE in only one state)
 
Posted by TwinStarRocket (Member # 2142) on :
 
The 35W bridge was a "spandrel braced" arch bridge, a combination of beam and arch bridge. The arch was very slight, which is probably why the bridge deck could fall 64 feet into the river while remaining mostly horizontal. It is amazing so many survived this fall, some even walked away. The truss hitting the river bottom probably absorbed some shock, along with car suspensions and tires.

I was an engineering school dropout who watched this bridge being built.
 
Posted by George Harris (Member # 2077) on :
 
Thanks
 
Posted by train lady (Member # 3920) on :
 
Thanks to both of you for answering the question. But George seeing that long range worrying and an over active imagination are some of my specialties I wonder if the freight couldn't weaken an already weakend spot and the addition of a passenger train cause the final blow. I realize that this is a very slim chance but couldn't it occur?
 
Posted by George Harris (Member # 2077) on :
 
Train lady, I don't know quite how to deal with your long range worrying other than to quote, "Sufficient unto the day is the evil thereof" which realize really does not solve anything for you.

Yes, it is a very slim chance, more like extremely slim. You must also understand that a lot of design and analysis effort deals with thing that approach the slim and none level of possibility. It must, because slim and none occassionally happens.

Katrina was a good example of this. The engineers involved wanted stronger and higher levees because they knew that they were only good enough for the likely largest likely storm in 50 years. The politicians basically told them go away, you are being worry warts and scare mongers. Of course they were aslo thinking, "50 years. So what? I will be gone long before then." (A "50 year" storm means the likely largest in any given 50 year period, but it also means that you have a 2% chance every year of having one.) Katrina was something like the 200 year plus interval storm, and by the nature of its path hit New Orleans hardest at the weakest point. The New Orleans levee system started off and and is still primarily oriented toward protection against flooding from the Mississippi River with Lake Ponchartrain being the relief from the flood, not the source of the flood. We may never again have a storm hit the New Orleans and Gulf Coast as hard as Katrina did, or we may at sometime, anytime, over the next century have an even bigger one. No one really knows and those that talk like they do are talking nonsense.

Back to your original question: As I said, yes, but highly unlikely. It was not a bridge, but the sort of thing that you describe is exactly what derailed the Texas Eagle near Marshall, Texas in 1983. Without going into a lot of details, the Texas Eagle was the third train to pass over what was a poorly done broken rail replacement. The new rail, not the old rail, shattered under the second or third car AFTER the TE's engines had passed over it. That is after carrying a few hundred axle loads of 20 to 32 plus tons, it shattered under an axle load of only about 15 tons. First and foremost lesson learned: The particular metallurgy of the new rail, a 1% chromium alloy, which was then being experimented with in the US, is no longer used, and so far as I know there is none left in track in the US. The improved hardness was gained at the cost of too much increase in brittleness. This is another of those things that supposedly worked great in Europe that some how rotted on the Atlantic crossing. It is no longer produced in Europe anymore, either.
 
Posted by train lady (Member # 3920) on :
 
Thanks George.
 


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