Collapse of New Bridge Underscores Worries About China Infrastructure

[qwerrty]

Not anti-Chinese at all but typical "if it bleeds it leads" mind-set of our media. Everyone gets tarred with the brush and few get painted nicely.

A new bridge should not fail so quickly..

not when you have 4 trucks weigh 100 tons each on a bridge section that can only take 55 tons max.

dont they have check points at each end for checking.. or they have, but get bribed by freighter companies and let through?


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It is not overloaded.

It's funny when people blame 4 truck made overloading a bridge. It's not as fragile as you think, unless it was stolen too much material.

Cần Thơ Bridge today:

we're taking about concentrated load from 1 vehicle, not small cars spreading evenly through out the bridge like in your pictures. the chinese bridge has 4 giant 100 tons overloading trucks on a single section. do the math..

 

[Solomon2]

not when you have 4 trucks weigh 100 tons each on a bridge section that can only take 55 tons max.

I learned in engineering school that the American practice is to design for 10x the rated static load. Four 100 ton-trucks moving across a new 55-ton bridge should not have collapsed it.

dont they have check points at each end for checking.. or they have, but get bribed by freighter companies and let through?

That's what weigh stations are for.

the chinese bridge has 4 giant 100 tons overloading trucks on a single section. do the math..

If they were all to the side the bridge might have suffered torsion box or torsion plate failure. But the bolts would have to be bad for that to happen. Such a failure would be expected within a few weeks of the section entering service.

 

[qwerrty]

I learned in engineering school that the American practice is to design for 10x the rated static load. Four 100 ton-trucks moving across a new 55-ton bridge should not have collapsed it.

pointless.. 10x of how much static load? 1t? 2t? 5kg? 100kg? 3000t?
why don't you post the legally weight of a vehicle can be on a concrete landbridge in america? i know in ausrtralia only allowerd no more than 43 tons. it shouldn't be different anywhere else in the western world..



from wiki

In the late 1950s, the American Association of State Highway and Transportation Officials (AASHTO) conducted a series of extensive field tests of roads and bridges to determine how traffic contributed to the deterioration of pavement materials. In 1964, the AASHTO recommended to Congress that a bridge formula table be used instead of a single gross weight limit for trucks. The Federal-Aid Highway Act Amendments of 1974 established the bridge formula as law, along with the gross weight limit of 80,000 pounds (36,000 kg), still in use as of 2009.[2]

 

[Solomon2]

^^^^
qwerrty, that's to avoid deforming asphalt or crushing concrete into sand. Not so much to do with bridge loading. Specially constructed trucks are permitted to carry loads heavier than 40 tons.

 

[VCheng]

^^^^
qwerrty, that's to avoid deforming asphalt or crushing concrete into sand. Not so much to do with bridge loading. Specially constructed trucks are permitted to carry loads heavier than 40 tons.

The key figures are load per axle and tire contact patch and pressure.

 

[shuttler]

But this seems a case of a new scissor getting broken because the thickness of the shirt was higher than normal...

you are lost. what I meant was referring to the great name simple mind that "new"-ness of any material can be easily succumbed to a much greater pressure exerted on it !

 

[shuttler]

A section of the bridge broke because it could not withstand the pressure exerted on it, as simple as that. It was not known that vietnam can build the greatest bridges on its own. Nor canada / american's civil engineering prowess at building bridges can rule the world as if no body can match that. civil engineering - india? forget it.

The standard procedures are
1. architectural blue prints have to be submitted to structural depatments for approval 2.the material to be used have to be lab-tested to comply with a stipulated ksc requirement. 3. During commissioning, there are site supervisors to safeguard the quality standards and 4. quality surveyors to certify the final quality of work. As I said, the overweight of the trucks were the biggest problem but I do not rule out foul play.

We have world class engineers and have built more high quality state of the art bridges than the ones that have collapsed.

 

[qwerrty]

wrong link

 

[Black Widow]

Really? unfortunately reality don't agree with you though, vietnamese bridge collapsed even unloaded, how do you like it?
Bridge section collapses in Vietnam; 43 dead - Houston Chronicle

BRIDGES COLLAPSIN

Thats why Indian don't make bridges...

 

[qwerrty]

^^^^
qwerrty, that's to avoid deforming asphalt or crushing concrete into sand. Not so much to do with bridge loading. Specially constructed trucks are permitted to carry loads heavier than 40 tons.

this is AASHTO legal safe loads for typical highway bridges in america. still need to go through checking at the station and may need spercial permits and change configs if heavier.

the chinese truck is type 3-3 unit and four of them way more heavier than america legal loads. some of you here say not overloading?

 

[huskie]

this incident is astonishingly similar to the one that took place one year ago in the Zhejiang Province: both ramps tipped over due to extremely overloaded trucks stopping/driving in the same lane, causing extreme uneven pressure distribution beyond the design limit. keep in mind that this is very different from the scenario where regular trucks jam the road during rush hours--the ramp is designed to handle this but not extreme overloading. quality issues do arise in various Chinese infrastructure projects, but based on the picture showing that the concrete box girder is almost intact after the fall, there is not much evidence of quality issue being the major cause in this particular case.

now there are two ways to prevent this from happening. the first approach is to increase the designed limit that the elevated roads/bridges can handle, just like a lot of brainless liberals are crying for: the design "should have" considered overloading issues. unfortunately handling extreme overloading in the design phase is unrealistic and impractical, it's like asking the car manufacturers to make all vehicles as strong as military tanks to prevent injury from crashes. the second approach is to keep the insanely overloading trucks off the roads. now this is much more realistic, however, I don't see any possibility of eliminating the epidemic overloading problem in the near future due to a lot of complicated reasons. So sadly I won't be surprised to see more such incidents.

 

[HellzHere]

One collapse should not be used to generalize.
China has developed its infra at a great rate,have to agree to that!

 

[ahfatzia]

One collapse is one too many, however, dwelling on past mistakes is not a solution. An oversight committee must set up to recheck all the bridges and overpasses to ensure future mishaps do not happen. Any new projects also must sign off by the same committee.

 

[Riteon]

How the heck could one truck weigh 100 Tons !!....whihc truck was it !!....that must be one awesome trailer !!1