Should all bridges have height signs?

Davy

Something I have been thinking about lately, most bridges have no height indication whatsoever. Any thoughts?

mallachyrivers

why would you need to know the height of a bridge if you drive/walk over it anyway?

Davy

mallachyrivers wrote: »

why would you need to know the height of a bridge if you drive/walk over it anyway?

As you drive under them with a truck. Only low bridges have warnings with exact heights. Most bridges along main routes have no indication. A standard rigid or artic might do but how is any other load meant to know the bridge height

mallachyrivers

oh right, i never thought. thanks

Aidan1

Could it just be that the unmarked bridges are above the maximum height limit for road use (used to be 16'4'' I think?), and because you shouldn't be travelling with a load any higher than that, there's no need to mark it?

Davy

Aidan1 wrote: »

Could it just be that the unmarked bridges are above the maximum height limit for road use (used to be 16'4'' I think?), and because you shouldn't be travelling with a load any higher than that, there's no need to mark it?

Where does that figure come from? Never heard of a maximum height restriction

corktina

surely all bridges should have some form of marking in case a restriction sign should fall off a low one.

mike65

You'd imagine is self evident that there should be markings on every structure under which traffic passes. Whether anyone will take notice is another matter - isn't there a bridge in Portlaoise that keeps getting hit?

Davy

Davy wrote: »

As you drive under them with a truck. Only low bridges have warnings with exact heights. Most bridges along main routes have no indication. A standard rigid or artic might do but how is any other load meant to know the bridge height

I would say that only bridges that are lower than the current standards should be marked.

In Cyprus ALL bridges have height signs, this has the amusing result in some bridges in mountainous areas having signs that read 10.9m or more.

Aidan1

Where does that figure come from? Never heard of a maximum height restriction

I was wrong, it's 4.65m (which works out at 15.255ft). It's from S.I. 366 of 2008.

Davy

mike65 wrote: »

You'd imagine is self evident that there should be markings on every structure under which traffic passes. Whether anyone will take notice is another matter - isn't there a bridge in Portlaoise that keeps getting hit?

Are you talking about the railway bridge? Not sure which rail line it is, but that one is well protected and signed.

Aidan1 wrote: »

I was wrong, it's 4.65m (which works out at 15.255ft). It's from S.I. 366 of 2008.

Vehicles and trailers first licensed prior to 1st Nov 2008 have until 1st November 2013 to comply to that, so what if one of them hits a bridge. Even places like garages aren't marked properly some with no markings, are these are more around the 4.2m. Anything less then 5m/6m would make sense for compulsory marked imo

L1011

I've seen markings up to 5.3M but nothing higher than that, and few above 4.8M

corktina

Deleted User wrote: »

I would say that only bridges that are lower than the current standards should be marked.

.

just to repeat myself, what if the sign falls off? the bridge then would appear to meet the current standars.

Davy

MYOB wrote: »

I've seen markings up to 5.3M but nothing higher than that, and few above 4.8M

What kinda of roads? Based in the same local council?

-Corkie-

Davy wrote: »

What kinda of roads? Based in the same local council?

Are you the same Davy on Irishrigs???:)

corktina

corktina wrote: »

just to repeat myself, what if the sign falls off? the bridge then would appear to meet the current standars.

If a bridge is low enough to risk being struck, then the onus would be on the owners to ensure the (one and only) sign doesn’t fall off, painting it on for example or just by having multiple signs warning stripes etc.

L1011

Davy wrote: »

What kinda of roads? Based in the same local council?

Generally new motorway overbridges (well, underbridges in the motorway - where the newer motorways cross existing roads). Think the Luas bridge at Leopardstown Park Hospital is signed as 5.2 also. All over the country.

corktina

Deleted User wrote: »

If a bridge is low enough to risk being struck, then the onus would be on the owners to ensure the (one and only) sign doesn’t fall off, painting it on for example or just by having multiple signs warning stripes etc.

not much help in a scenario where the sign HAS fallen off and an HGV has hit the bridge, dislodging it and dumped a train in the bus lane!

I believe the OP was proposing a fail safe method where all bridges had an indication...maybe a sign painted on the bridge behind the nailed on sign saying "danger sign fallen off" (Irish solution, may not get an E mark from Brussells)

Davy

-Corkie- wrote: »

Are you the same Davy on Irishrigs???:)

Nope, never heard of the site till you mentioned it, sorry if I disappointed ya :pac:

MYOB wrote: »

Generally new motorway overbridges (well, underbridges in the motorway - where the newer motorways cross existing roads). Think the Luas bridge at Leopardstown Park Hospital is signed as 5.2 also. All over the country.

Just was curious if they were in the same CC area as in they had a plan/procedure to deal with it.

Just to be be clear, Im not really talking about bridges under 4m as they are already marked, well should be anyway.

murphaph

What about other overhead items like power and telephone lines? Should we sign every single one of them as well?

No. Once bridges are above a certain height then they are fine. Drivers of outsize loads know they have to take special precautions.

Davy

murphaph wrote: »

What about other overhead items like power and telephone lines? Should we sign every single one of them as well?

They are much higher in most cases. The only thing might be telephone lines on very minor roads.

Aidan1

Much more of a problem than you'd think - a lot of phone lines are very low, even in villages and towns. Normal artics don't have much of a problem in most cases (natural selection and all that), but even slightly outside loads (a load of big square bales being an obvious example) can cause problems if they're just taller than the average.

That's part of the reason for a maximum height - it makes the burden of responsibility clear if someone pulls something down.

I'm fairly sure there was a previous maximum height previous to 2008 - it may only have been advisory, but it was always used in loading trucks to ensure that you didn't have a problem with cables (or the Gardai!).

Saw a mobile haystack stuck under a bridge on the Athlone bypass on Tuesday evening.

Surely, it would make sense for transport companies to have loading gauges in their yards so that vehicles don't leave overheight.
Here is an example of one uesd on a railway yard.

spacetweek

I have never noticed a missing sign.
Why do people keep wondering what would happen if the sign fell off? When does that ever happen?

There is a maximum vehicle height restriction (controversially abolished in 1995 and reintroduced 2008 as a result of the Dublin Port Tunnel) and the rule is that if a bridge is over this height, it doesn't need to be signed. Pretty straightforward.
I really don't see what the problem is!

Deleted User wrote: »

Surely, it would make sense for transport companies to have loading gauges in their yards so that vehicles don't leave overheight.
Here is an example of one uesd on a railway yard.

It's highly likely they do have those.

Aidan1

Dolanbaker - the nature of hauling straw is that it's generally loaded in fields or farmyards, well away from hauliers own yards. Also, a lot of hauliers that bring straw westwards are very small operators (owner drivers) who often buy and sell on spec - they tend to pile 'em high on the basis that their margin per load is entirely dependent on how many bales they can cram onto a truck.

That said, because bales are a regular size, it's very easy to work out what height a load is, so there is really no excuse. Not that it stops people from overloading, or just plain failing to pay attention to low bridges.

Hoof Hearted

It's not a big deal if a bale of hay hits a bridge. Also if a low telephone wire is hit, again not so serious. But a driver will get the shíts approaching a bridge that may be missing its height sign due to corrosion, vandalism, etc. and I have seen this in the past.

Davy

Sorry for bumping, but I noticed some railway crossings and toll plazas had height signs and both were around the 5m mark so not exactly low. Nearly all bridges along the m50 have a mark or lump so it is happening

dubhthach

As far as I know the standard bridge height on Motorway bridges is 5.5metres. Obviously with widening of the M50 you get a situation where inside lane mighten be that high (I'm thinking up at N3 junction for example).

Davy

dubhthach wrote: »

As far as I know the standard bridge height on Motorway bridges is 5.5metres. Obviously with widening of the M50 you get a situation where inside lane mighten be that high (I'm thinking up at N3 junction for example).

Are you sure they are that high? Doesn't seen like there is that much clearance. The different heights is also a thing, least the railways used to mark their bridges width for the height

dubhthach

Davy wrote: »

Are you sure they are that high? Doesn't seen like there is that much clearance. The different heights is also a thing, least the railways used to mark their bridges width for the height

Well going by below from Dáil it seems I'm 20cm out (0.2m) it mentions 5.3m for Motorway bridges, compares it to 5.5m for the Dargan bridge in Dundrum (Luas)

http://historical-debates.oireachtas.ie/S/0179/S.0179.200502090008.html

Davy

dubhthach wrote: »

Well going by below from Dáil it seems I'm 20cm out (0.2m) it mentions 5.3m for Motorway bridges, compares it to 5.5m for the Dargan bridge in Dundrum (Luas)

http://historical-debates.oireachtas.ie/S/0179/S.0179.200502090008.html

Kinda odd but the first bridge southbound on the M7 at the ball has a sign in the median displaying 4.95m about 100 meters before it. Only noticed it on Wednesday, anyone know if it's new?

niloc1951

Davy wrote: »

Kinda odd but the first bridge southbound on the M7 at the ball has a sign in the median displaying 4.95m about 100 meters before it. Only noticed it on Wednesday, anyone know if it's new?

Its been there since the early naughties when SDS, now An Post parcel service, put some super cube trailers on the runs out of Dublin from their depot on the Naas Road to Portlaoise and Cork.

On a wet night while being unloaded rain was cascading down from the roof of one of the trailers onto the loading dock. On inspection it was found the the gutter had been bent flat, it was assumed that while running unloaded a bounce coincided with passing under the bridge in question.

In the UK bridges with a clearance of less than 16'6" (5.029m) are signed as super cube trailers are in common use there, the EU regulation for international traffic is 4.0m.

In Europe you will see many tractor units with reduced size rear wheels. This gives two benefits, it reduces the overall hight of the trailer to comply with the 4.0m rule, it also reduces fuel consumption by reducing the frontal area.

As an aside, would it not be better to plane off a few centimetres from the road surface beneath the bridge in question instead of routing HGV's through the centre of Naas with all the attended negative environmental impact such vehicles bring with them.

niloc1951

niloc1951 wrote: »

As an aside, would it not be better to plane off a few centimetres from the road surface beneath the bridge in question instead of routing HGV's through the centre of Naas with all the attended negative environmental impact such vehicles bring with them.

Probably better to jack up the bridges, otherwise motorway traffic would experience a "yump" as the vehicle drops and rises again, either that or plane several hundred metres and relay to avoid a sudden change in height.

niloc1951

Deleted User wrote: »

Probably better to jack up the bridges, otherwise motorway traffic would experience a "yump" as the vehicle drops and rises again, either that or plane several hundred metres and relay to avoid a sudden change in height.

Can't resist :D

'yump' originated from Scandinavian rally drivers way back in the '60's to describe their airborne travel after driving extremely fast over a sudden but short elevation in the road which caused the car to 'jump' off the road. A real expert in the art could travel over five car lengths before touchdown.

Couldn't really see a 44t artic doing this .

Seriously though, the phenomenon you describe is not at all uncommon on your primary route network, there is a particularly good one which can give the stomach a real sinking feeling on the westbound side of the N25 west of the Cobh slip.