Flyover collapse in Hubei, China

[bugbus]

"Four people died and eight were injured after a section of a highway flyover in China’s central Hubei province collapsed, according to Chinese authorities."

https://apnews.com/article/business-china-beijing-accidents-a955fd8cd41d5819581ac223b1799172

Looks like some kind of heavy load platform caused the section of bridge to overturn. The structure itself appears to be in surprisingly good shape.

I would be interested to know what the platform was carrying and how heavy it was.

Does anyone know if bridges in China are designed for these sorts of vehicles, and whether there are any restrictions on lane position as there are in other parts of the world (e.g. Australia)?

 

[bugbus]

A couple of clearer pictures of the payload.

Maybe some kind of electrical equipment?

 

[Cool_Controls]

Looks like SPMTs carrying something. The heads on those columns look a bit small.

 

[bugbus]

The heads on those columns look a bit small.

Are you referring to the width of the crosshead/headstock at the two end piers? The proportions don't look unusual to me.

 

[hokie66]

Many wheels/axles on the trailers, probably intended to distribute the load longitudinally, but that was never going to happen. The single column intermediate supports didn't help, especially on a horizontal curve. And there doesn't appear to be anything at the end supports to prevent rotation.

 

[bugbus]

And there doesn't appear to be anything at the end supports to prevent rotation.

There would have (or should have) been a pair of bearings at the end piers, which would provide rotation restraint to the bridge section.

Seems like it wasn't enough to prevent one side lifting up.

Was the load platform right along the edge of the bridge? In Australia these things have to drive along the CL of the carriageway +/- 1 m.

 

[hokie66]

Maybe the bearings were only for gravity loading, not uplift?

 

[bugbus]

Maybe the bearings were only for gravity loading, not uplift?

That seems to be the reason for the failure in my opinion. In my (limited) experience it is not common for bearings to be specifically designed to resist uplift, though it can be done. And even where uplift tends to occur, there can be easier way to avoid it, e.g. by adding ballast to certain parts of the superstructure, mandating particular positions for very heavy vehicles such as this one, etc.

My bet is that the load platform / SPMT was driving close to the barrier on the outside of the curve for some reason.

 

[AusG]

"The newspaper Beijing News said the truck (198t) was four times over the allowable weight limit on the flyover..." The load has a little extra leverage on the outside of the curve too, of course. Can we put this one down to operator error?

 

[mk3223]

The extra long SPMT isn't really help to reduce the load per axle as the overweight equipment was concentrated in a small section. It's an operation error in combination with the engineer and maintenance mistakes.

 

[JStephen]

Those orange pieces are a bridge section that spans between the two ends to spread the load out. See typical rig here:

https://www.youtube.com/watch?v=FZq2Y4dh4hk

In the US, anything over the normal weight limit requires permits from the state (and perhaps local) highway departments. I have no idea how things work in China.
Electrical transformers are a common compact super-heavy load on the Youtube videos, but no idea if that's what that was.
A failure like this could be due to somebody routing the load the same way, or an underdesigned/underbuilt bridge, or operator getting on the wrong road, or operator being instructed to use the wrong road, etc. IE, could have been a failure in a lot of different ways, and no way to tell without detailed information.

 

[hokie66]

So perhaps those orange load spreader were themselves unstable. If one or both rotated, the transformer falling onto the trailer bed would be a massive impact force.

 

[JohnRBaker]

Yes, it looks like the WRONG thing in the WRONG place at the WRONG time.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Artisi]

Would have been better travelling on the "wrong" side of the road closer to the centre strip, more than likely wouldn't have rotated the roadway. Poor planning /advice, as this is China - heads will roll, the hierarchy will have to save face.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[JohnRBaker]

Yes, if he had been hugging the inside of the radius it might have held. If this was a two-way section of highway, they should have blocked that road so that he could have driven in the left lane, thus being nearer the inside of the radius.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[davidbeach]

Whether it would have helped in this situation or not, those types of loads need enough leading and trailing pilot cars (usually pickup trucks) to allow the load to have what ever part of the roadway it needs. There was a situation in Portland many years ago where a large concrete beam rolled over, on the upper deck of a two level bridge. No harm to the bridge in that case fortunately, but there was a fatality. It was believed afterward that the load would have been fine if it had kept moving, but stopped in late afternoon traffic (at a place and traffic condition that that type of load should never have been allowed), the load eased over. The "driver" of the rear support reported that it very slowly rolled over until it completely fell over. One fatality as I recall. That direction on that bridge, closed at that time of day and all heck broke loose as could be expected.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[TugboatEng]

As large as this transformer is, this may have significant ramifications considering the blackouts China is already experiencing.

 

[davidbeach]

We can only hope that it was intended for the local market and not enroute to a seaport for shipment elsewhere...

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[TugboatEng]

I must assume local use as a company delivering transformers of this size for worldwide use would likely have a track record of doing so and not suddenly quadruple the ratings of the local infrastructure.

DB, here in California one of our more modern constructions (1970's I think) was the merge of highway 24 and 680. I have heard truck drivers comment on the perfect banking of the curve so that they don't need to slow at all. The trouble is, few trucks actually use that route.

 

[hokie66]

That load, and thus the transformer, is not THAT big. 200 tons. Some two axle mining trucks are heavier than that. And the heavy lift which JStephen linked about was something like 460 tons.

It looks like the roadway over the bridge was closed. Otherwise, a bunch of cars would have been dumped, and the pictures don't show that.