Bridge collapse on M20

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Discussion

Getragdogleg

8,766 posts

183 months

Wednesday 31st August 2016
quotequote all
saaby93 said:
DAVEVO9 said:
Bit of an update..

Taken off trucknet.com

On Auto Renovations FB page.

After speaking to a mate just now, i now have some facts for you all the lorry was on the hard shoulder as i said he had stopped with a possible blow out after checking the tyres were ok the driver headed up the hard shoulder gaining speed to join the carriageway the vehicle its self is tracked and in the tracker the maximum speed the lorry got up to before the impact was 21mph and then stopped dead, yesterday the police measured the height of the digger arm and was found to be at 16'7" with the bridge still on the front of the trailer and the airbags on the trailer at full stretch on the axle straps, today once the bridge had been removed and the trailer had settled at running height the digger arm was measured again and was found to be 16'6, so as it states that all bridges on any motorway should be no lower than 16'6 unless stated. And as the driver had picked the digger and dumper up from the roadworks on the London bound section under junction 4 the lorry and load had passed under at least 4 other bridges in lane 1 before coming to this one and never touched any of them. These are facts and not opinion. Thanks for reading
Depends whether height over the hard shoulder is allowed to be lower.
I know everybody hates Lorries and lorry drivers but this times this is a case of the bridge being too low, the 16ft 6 height of the load is not really the problem here its the bridge height on the far left side. The hard shoulder was in use for its intended purpose and the driver of the lorry was acting as he should by checking his tyre and then when leaving the hard shoulder building up speed before joining the main motorway.

The pictures of the end of the jib that struck the bridge show marks that are quite a lot lower than the top of the jib, several inches lower in fact.

The bridge is at fault, even more so if the height was not marked clearly as required if its 16.6 or lower.

If the bridge was 16.6 and the digger was 16.6 this would have been a scrape on the underside of the bridge and a scratch on the top od the digger arm.

Nice to see the driver secured the load well, even after a massive impact the digger stayed put and did not come loose or fall off.


Digga

40,317 posts

283 months

Wednesday 31st August 2016
quotequote all
Exactly as I thought yesterday.

scenario8

6,561 posts

179 months

Wednesday 31st August 2016
quotequote all
Remarkable, if true, for the issue not to have arisen earlier in the life of that bridge. It's not like it is a road less travelled by HGVs.

The physics involved is interesting too. That many tonnes travelling at that relatively low speed tapped that much mass that distance while creating that little damage (to the truck and load). Do it again so I can watch, please!

Digga

40,317 posts

283 months

Wednesday 31st August 2016
quotequote all
scenario8 said:
Remarkable, if true, for the issue not to have arisen earlier in the life of that bridge. It's not like it is a road less travelled by HGVs.

The physics involved is interesting too. That many tonnes travelling at that relatively low speed tapped that much mass that distance while creating that little damage (to the truck and load). Do it again so I can watch, please!
There were a fairly unique set of events to cause this. It would seem the only reason it had not previously occurred is that no HGV ever traveled under the bridge whilst on the hard shoulder.

As for the physics and the damage to the excavator being so slight, it did fox me at first, because every other instance of "digger on low loader hits bridge" looks something like this:



or this:



Severe damage to the excavator, and a clear 'contact' mark on the bridge itself. Loaded in a controlled way, the box-section boom arm on a digger is extremely strong and this took the load very well.

SilverSpur

20,911 posts

247 months

Wednesday 31st August 2016
quotequote all
Immovable object that bridge, probably weights 5000 tonnes and is security attached to the ground, and is reinforced in order to carry traffic. not some lightweight 300 tonne pedestrian bridge that's in two sections already and dos the have to carry weight.

saaby93

32,038 posts

178 months

Wednesday 31st August 2016
quotequote all
SilverSpur said:
Immovable object that bridge, probably weights 5000 tonnes and is security attached to the ground, and is reinforced in order to carry traffic. not some lightweight 300 tonne pedestrian bridge that's in two sections already and dos the have to carry weight.
Did the pedestrian bridge have anything in its mountings to prevent it being tapped sideways?
There may have been nothing as they might prefer the section to move rather than topple the whole bridge

KTF

9,805 posts

150 months

Wednesday 31st August 2016
quotequote all
CAPP0 said:
DAVEVO9 said:
Bit of an update..

Taken off trucknet.com

On Auto Renovations FB page.

After speaking to a mate just now, i now have some facts for you all the lorry was on the hard shoulder as i said he had stopped with a possible blow out after checking the tyres were ok the driver headed up the hard shoulder gaining speed to join the carriageway the vehicle its self is tracked and in the tracker the maximum speed the lorry got up to before the impact was 21mph and then stopped dead, yesterday the police measured the height of the digger arm and was found to be at 16'7" with the bridge still on the front of the trailer and the airbags on the trailer at full stretch on the axle straps, today once the bridge had been removed and the trailer had settled at running height the digger arm was measured again and was found to be 16'6, so as it states that all bridges on any motorway should be no lower than 16'6 unless stated. And as the driver had picked the digger and dumper up from the roadworks on the London bound section under junction 4 the lorry and load had passed under at least 4 other bridges in lane 1 before coming to this one and never touched any of them. These are facts and not opinion. Thanks for reading
Kinda stacks up with what I said/asked yesterday evening.
Would the fault still be on the driver or is it now a grey area if the bridge wasnt quite in spec?

SilverSpur

20,911 posts

247 months

Wednesday 31st August 2016
quotequote all
I think it's a grey area, the truck isn't dramatically badly loaded. How exactly does a driver know if a truck is loaded to 16'6" anyway? Wonder how many special instruments the police have had to use to determine its exact load height? To the inch?

And what exactly was the height of the bridge at the impact point?

All seems to be very marginal to me.


Let's just call it an unfortunate accident due to unforeseen circumstances, be thankful it didn't involve a bus load of school kids and a petrol tanker, learn from it, check all other bridges, help the injured motorcyclist.

Digga

40,317 posts

283 months

Wednesday 31st August 2016
quotequote all
Well to the letter of the law, it's not the truck driver's fault now. The police appear to have satisfied themselves that the load did not breach guidelines, therefore the only conclusion is that the bridge does not meet spec. That the main traffic carriageways were in spec is incidental, this truck just happened to need to use the hard shoulder and should have been able to do so.

All IMHO of course.

DAVEVO9

3,469 posts

267 months

Wednesday 31st August 2016
quotequote all
Digga said:
Well to the letter of the law, it's not the truck driver's fault now. The police appear to have satisfied themselves that the load did not breach guidelines, therefore the only conclusion is that the bridge does not meet spec. That the main traffic carriageways were in spec is incidental, this truck just happened to need to use the hard shoulder and should have been able to do so.

All IMHO of course.
I agree with all of that Digga.

Trif

748 posts

173 months

Wednesday 31st August 2016
quotequote all
SilverSpur said:
Let's just call it an unfortunate accident due to unforeseen circumstances.
So who pays? I can't see the insurance company taking it lightly with the lorry being in spec.

SilverSpur

20,911 posts

247 months

Wednesday 31st August 2016
quotequote all
Trif said:
So who pays? I can't see the insurance company taking it lightly with the lorry being in spec.
HA for the met part, insurers to cover other costs.

essayer

9,065 posts

194 months

Wednesday 31st August 2016
quotequote all
Ultimately, if 16'6" (or 5m?) is the minimum height of motorway bridges, it doesn't seem at all sensible to run with a 16'6" load height.

The trailer will move about under motion, roads get resurfaced and repaired, a concrete bridge would have some amount of temperature-related expansion .. etc

Think the driver will be on the hook for this

heebeegeetee

28,735 posts

248 months

Wednesday 31st August 2016
quotequote all
essayer said:
Ultimately, if 16'6" (or 5m?) is the minimum height of motorway bridges, it doesn't seem at all sensible to run with a 16'6" load height.

The trailer will move about under motion, roads get resurfaced and repaired, a concrete bridge would have some amount of temperature-related expansion .. etc

Think the driver will be on the hook for this
I agree re the wisdom of running with a load 16'6 high, however if the law states that bridges below that must be signed, and here is a bridge that is lower and not a warning sign in sight...

There are road markings that seem to indicate vehicles must not pass on the hard shoulder under the bridge, but I wonder how much advance warning there is of those?

AgentZ

272 posts

128 months

Wednesday 31st August 2016
quotequote all
heebeegeetee said:
I agree re the wisdom of running with a load 16'6 high, however if the law states that bridges below that must be signed, and here is a bridge that is lower and not a warning sign in sight...

There are road markings that seem to indicate vehicles must not pass on the hard shoulder under the bridge, but I wonder how much advance warning there is of those?
Those road markings are on the opposite carriageway and also just the end of the fourth lane rather than avoid bridge markings?


If it proves to be true the load was at 16'6 max then it was pushing things to the limit but Motorway bridge minimum heights before signage seems to be a very grey area. I've seen 16'3, 16'6, 16'9....

There are other low looking bridges he must have passed under so I would have those measured (and checked for recent damage) in lane one and hard shoulder and see what they are.

rolando

2,149 posts

155 months

Wednesday 31st August 2016
quotequote all
As I understand it, only bridges 16' 3" or lower require a warning

See https://www.gov.uk/government/uploads/system/uploa...

98elise

26,585 posts

161 months

Wednesday 31st August 2016
quotequote all
Elysium said:
CAPP0 said:
DAVEVO9 said:
Bit of an update..

Taken off trucknet.com

On Auto Renovations FB page.

After speaking to a mate just now, i now have some facts for you all the lorry was on the hard shoulder as i said he had stopped with a possible blow out after checking the tyres were ok the driver headed up the hard shoulder gaining speed to join the carriageway the vehicle its self is tracked and in the tracker the maximum speed the lorry got up to before the impact was 21mph and then stopped dead, yesterday the police measured the height of the digger arm and was found to be at 16'7" with the bridge still on the front of the trailer and the airbags on the trailer at full stretch on the axle straps, today once the bridge had been removed and the trailer had settled at running height the digger arm was measured again and was found to be 16'6, so as it states that all bridges on any motorway should be no lower than 16'6 unless stated. And as the driver had picked the digger and dumper up from the roadworks on the London bound section under junction 4 the lorry and load had passed under at least 4 other bridges in lane 1 before coming to this one and never touched any of them. These are facts and not opinion. Thanks for reading
Kinda stacks up with what I said/asked yesterday evening.
A 16'"6 truck is not going to pass comfortably beneath a 16"6' bridge!
That's what engineers would call an interference fit smile

AgentZ

272 posts

128 months

Wednesday 31st August 2016
quotequote all
rolando said:
As I understand it, only bridges 16' 3" or lower require a warning

See https://www.gov.uk/government/uploads/system/uploa...
The question I would ask: Is that leaflet only talking about non-Motorway bridges?

Trif

748 posts

173 months

Wednesday 31st August 2016
quotequote all
essayer said:
Ultimately, if 16'6" (or 5m?) is the minimum height of motorway bridges, it doesn't seem at all sensible to run with a 16'6" load height.

The trailer will move about under motion, roads get resurfaced and repaired, a concrete bridge would have some amount of temperature-related expansion .. etc

Think the driver will be on the hook for this
5.1m isn't it? So 1" of clearance at a minimum. If you are under the stated limit, you would reasonably expect to be able to travel under a bridge without it falling on you. Perhaps the guidance should be changed to you are not allowed to take a vehicle exceeding 15'6 on the roads (leaving a minimum of a foot of clearance).

You also have the problem of, bridges being a common site on motorways and if you end up approach one smaller then your load, you are very limited on what you can do to resolve the situation.

Edited by Trif on Wednesday 31st August 15:27

saaby93

32,038 posts

178 months

Wednesday 31st August 2016
quotequote all
Cant someone get out there with a tape measure to check the height of the abutment?
Or raise the arm of a digger to the same height