Suspension bridge in Phichit collapses before opening

[metisdead]

A troll post with racial slur has been removed.

[phoenixdoglover]

This is a 2-tower cable stayed design.

The towers (concrete) are in compression from the downward force of the cables (weight of the bridge)

The cables are in tension.

The deck longitudinally (lengthwise) is also under compression.

The towers are basically intact. The one failed horizontal tower member probably failed during the collapsed due to the tower being "torqued" by uneven weighting. That suggests the left side weight unloaded, the tower torqued counter-clockwise, and the horizontal beam failed, before the right side also unweighted.

The cable counterweights (ground level attachment points, with a massive hunk of concrete below ground) at one end appear intact; and there are no views of the other end. It is conceivable the counterweights on the far end moved, but unlikely, as they are normally over-designed. However, if they were truly eroded underneath, that would be a major factor.

The deck design looks light duty. The railing system provides no structural stiffening, and the deck beams look like a simple arrangement without much diagonal bracing. It looks like the railing posts were directly welded to the tops of the main deck beams. This does not inspire confidence; the beam strength could have been compromised by welding.

I am speculating it was deck failure, followed by cable failure on one side, then cable failure on the other side. Photos from the far end would be necessary to make a truly educated guess.

It is typical in bridge design/construction to copy a successful design and reapply it. Over time, the design may be used for longer and longer spans; which means the design viability ultimately will be exceeded. Longer spans require more attention to the strength/stiffness of the deck. I believe this was the main issue with 20th century suspension bridges, which led up to the spectacular Tacoma Narrows failure...too long and too flexible for the longer span.

Will there be a real engineering investigation in the case of this bridge? I highly doubt it.

[Artisi]

Meanwhile back in Farangistan..

http://www.foxnews.com/us/2015/07/22/interstate-10-in-california-to-reopen-friday-after-bridge-collapse/

And, even better:

https://www.google.com/search?q=bridge+collapse&es_sm=93&tbm=isch&tbo=u&source=univ&sa=X&ved=0CDoQsARqFQoTCLOxwvvD7sYCFUGnlAod7xsBHg

Let's not forget Galopping Gertie built in the almighty, all powerful, all wonderful, all perfect yoo-ess-eh?

I think if you cared to investigate closely and review the engineering reports on the Tacoma bridge failure you might see / learn there is a major difference in the mode of failure between these two events.

The I-10 bridge in California that failed was nearly 60 years old.

You can always find a reason to claim that an "engineering misjudgment" back home isn't the same as a "complete and utter incompetent screw-up" here in Thailand.

But they really are the same thing.

It's that 4th Law of Thermodynamics: "Poop happens".

The main difference being that a bridge failure in the west would normally undergo a full and througher engineering study to establish the cause. Will it happen here -'--

Edited July 24, 2015 by Artisi

[eddie61]

Phichit with suspension bridge was pushing the envelope......

nice little earner I suspect

[kaorop]

"Local authorities said fortunately it collapsed before the official opening otherwise many people would have died and injured."

Nice spin.

Sometimes I think they are trolling us.

No difference to every statement from the authorities.

they've been trolling the locals, since for ever