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moosehead
Joined: 05 May 2007
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 Posted: Tue Feb 17, 2009 8:28 pm Post subject: highway bridge near Hannam Market |
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if you've ever been to Hannam Market chances are you walked across this bridge - it's an overpass for pedistrians spanning a multilane highway - 6-7-8 lanes? very wide.
the thing is, the bridge is 5x as long as it is high - I've counted the supports on either side - the beams are the same - there is no support in the middle.
walking across one can feel the shaking from the cars, not just a little (as in other bridges) - but real shaking, shuddering. I've never seen a bridge this short span such a long distance before with no support in the middle.
reading another poster's thread about dangerous construction I thought of this bridge immediately. I've even thought about photographing it because it will come down eventually, either of its own accord or if someone actually decides to rebuild/reinforce it.
the bridge is also completely horizontal - no archway which would also even out the stress - virtually all the stress is spanning the length with the weakest in the middle.
it doesn't take an engineer (which I'm not and make no claims to be) to realize this bridge isn't stable. |
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Return Jones
Joined: 06 Feb 2004
Location: I will see you in far-off places
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| Posted: Tue Feb 17, 2009 9:33 pm Post subject: |
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There's a sign in Korean on the railing of the bridge that states that it's normal for that bridge to shake. I believe there's a brief explanation on the sign as well.
All bridges shake to a certain degree. If they don't, then they break. Same with airplane wings. There have been several high-profile roadway bridges collapse in North America over the past few years. It can happen anywhere. I agree, though, that the bridge you're mentioning does shake quite a bit, but I wouldn't worry about it. |
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wylies99
Joined: 13 May 2006
Location: I'm one cool cat!
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| Posted: Tue Feb 17, 2009 11:42 pm Post subject: |
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| All I can say is RUN across it! |
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sojusucks
Joined: 31 May 2008
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| Posted: Wed Feb 18, 2009 1:57 am Post subject: |
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| I have never noticed enough vibrations to make me worry. But who knows, it could fall apart underneath me. |
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moosehead
Joined: 05 May 2007
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| Posted: Wed Feb 18, 2009 3:16 am Post subject: |
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| Return Jones wrote: |
There's a sign in Korean on the railing of the bridge that states that it's normal for that bridge to shake. I believe there's a brief explanation on the sign as well.
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because it'd cost so much to replace it - 
look at the location - major thruway - and who wants to admit it needs to be replaced? I can just see the politicos lining up to declare it needs an upgrade
yes, all bridges do have what is referred to as sway - but this one is more than that. not only that but considering the amount of concrete on it - and the way it freezes and thaws due to weather - I mean honestly - just look at the bridge sometime - one can see how incredibly unbalanced it is.
I hate walking across it - but I do walk pretty fast any more - and if I didn't know better - I swear it shakes more these days than it used to. |
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JungMin
Joined: 18 May 2005
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| Posted: Wed Feb 18, 2009 3:35 am Post subject: |
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| Quote: |
| walking across one can feel the shaking from the cars, not just a little (as in other bridges) - but real shaking, shuddering. |
Ya, that bridge does get a bit wild in the middle sometimes. I wouldn't worry about it though, as hopefully its been designed properly - a bit of flex is a good thing sometimes. People don't notice it most times as engineers (yes, I am a civil engineer) try to keep it to a minimum because it tends to scare people like you. The tops of tall buildings can move a few meters in either direction under certain loads, but that doesn't mean it will fall down. Quite the opposite actually. |
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ellegarden
Joined: 01 Sep 2007
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| Posted: Wed Feb 18, 2009 3:39 am Post subject: |
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| JungMin wrote: |
| Quote: |
| walking across one can feel the shaking from the cars, not just a little (as in other bridges) - but real shaking, shuddering. |
Ya, that bridge does get a bit wild in the middle sometimes. I wouldn't worry about it though, as hopefully its been designed properly - a bit of flex is a good thing sometimes. People don't notice it most times as engineers (yes, I am a civil engineer) try to keep it to a minimum because it tends to scare people like you. The tops of tall buildings can move a few meters in either direction under certain loads, but that doesn't mean it will fall down. Quite the opposite actually. |
Couldn't it have a Tacoma Narrows effect happen to it? |
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JungMin
Joined: 18 May 2005
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| Posted: Wed Feb 18, 2009 3:46 am Post subject: |
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It could, but probably wouldn't be from the wind. It shakes now because of the traffic. So if the frequency of those forces generated by the traffic matched the natural frequency of the bridge, then yes, it the vibrations would grow out of control.
But like I said, if it's designed properly, that should have been taken into account. |
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itaewonguy
Joined: 25 Mar 2003
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| Posted: Wed Feb 18, 2009 8:11 am Post subject: |
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could always go around  |
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R-Seoul
Joined: 23 Aug 2006
Location: your place
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| Posted: Wed Feb 18, 2009 7:01 pm Post subject: |
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Moosehead, you�re a genius. You�re well thought out and not at all stupid sounding arguments lead me to suggest a career in civil & constructional engineering. Hey, why not apply for the entrance exams today � don�t bother studying as I�m sure you�ll fly through! ESL�s loss will be the world of constructions gain.
p.s. next time you visit that bridge, might I suggest jumping off it. |
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moosehead
Joined: 05 May 2007
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| Posted: Thu Feb 19, 2009 4:07 am Post subject: |
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| R-Seoul wrote: |
Moosehead, you�re a genius. You�re well thought out and not at all stupid sounding arguments lead me to suggest a career in civil & constructional engineering. Hey, why not apply for the entrance exams today � don�t bother studying as I�m sure you�ll fly through! ESL�s loss will be the world of constructions gain.
p.s. next time you visit that bridge, might I suggest jumping off it. |
let me get this straight - I post about a bridge that is clearly unbalanced, badly constructed and has the potential of killing and maiming people and you come back and fire off personal attacks against me?
that's really rich, dude, very very rich. |
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Ut videam
Joined: 07 Dec 2007
Location: Pocheon-si, Gyeonggi-do
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| Posted: Thu Feb 19, 2009 4:25 am Post subject: |
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| moosehead wrote: |
| let me get this straight - I post about a bridge that is clearly unbalanced, badly constructed and has the potential of killing and maiming people and you come back and fire off personal attacks against me? |
Granted, the guy was out of line in the way he said it...
... but I think the point he was trying to make is that you are utterly unqualified to be making statements like these. And it's a valid point. |
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moosehead
Joined: 05 May 2007
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| Posted: Thu Feb 19, 2009 10:32 pm Post subject: |
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| Ut videam wrote: |
| moosehead wrote: |
| let me get this straight - I post about a bridge that is clearly unbalanced, badly constructed and has the potential of killing and maiming people and you come back and fire off personal attacks against me? |
Granted, the guy was out of line in the way he said it...
... but I think the point he was trying to make is that you are utterly unqualified to be making statements like these. And it's a valid point. |
excuse me?? you know me personally do you??
obviously you don't - because if you did - you would know I am absolutely qualified to make this kind of statment - not only that - but ethically speaking I'm obligated to do so.
furthermore and as much as I detest repeating myself - this post is NOT about me - it's about what is a potentially lethal hazard to the health and well being of citizens who may use that bridge now or in the future.
jees - look at the bigger picture already |
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JungMin
Joined: 18 May 2005
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| Posted: Fri Feb 20, 2009 1:42 am Post subject: |
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You're not an engineer, but 'ethically' your qualified and obligated to do so? That's quite the different statement from your first post. Anyways, like YOU....I am looking at the bigger picture. I wouldn't label this walkway as unsafe without much more investigation. IF, and i said IF, you know what you are talking about then you know that deflections are a normal part of engineering and it depends of what the designing engineer had planned in his original designs. I wouldn't outright label this walkway as unsafe without much more information even though it get quite bouncy at times.
Anyways, you sound confused dude.....figure it out.
Last edited by JungMin on Fri Feb 20, 2009 2:42 pm; edited 1 time in total |
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mt01ap
Joined: 04 Nov 2006
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| Posted: Fri Feb 20, 2009 1:50 am Post subject: |
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I know that bridge and shop, it's right by the bowling alley.
Bouncy? yes.
Dangerous? I don't think so.
I don't think it's going to fall but I'm no engineer. |
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