Can we improve/implement bridge-strike protection measures?

[themickster.mg]

America has the Can-opener Bridge. It has a girder set above the road, to protect the bridge from being hit by high vehicles. Why don't any of our bridges have them? I'm guessing it's not that simple, otherwise we would.

 

[Bletchleyite]

I've seen these so it is possible. I guess just cost, but probably worthwhile if a given bridge is hit frequently. Though cost is still relevant in that case because the vehicle's insurer would be paying for repairs if they hit the bridge, not Network Rail.

 

[Egg Centric]

The usual reason given is that bridge strikes very rarely damage the bridge. OTOH if you add a sacrificial girder there's a reasonable chance of e.g. something nasty happening to pedestrians if they're next to it.

Having said that I don't see why those reasons don't also apply in the USA.

 

[Snow1964]

Most European countries have a default limit of 4.0m, ours are about 1m higher (just over 5m before being signposted as low)

Quite a strong case for any A and B road bridges that are low (because large vehicles tend to use them) to have a physical barrier. It is better to hit a beam than dislodge the deck

 

[Annetts key]

The most common vehicles that hit bridges are vans, lorries and HGVs. Of these, most have lightweight structures that form the top section. Against a brick, stone, concrete or metal girder bridge, the road vehicle normally comes off far worst.

The railway normally still inspects a 'bashed' bridge to check that the bridge structure hasn't been damaged. Because you never know what was inside the road vehicle that hit it. Or if the vehicle has left the scene, what the vehicle actually was.

Hence it's hardly surprising that the cost of providing protection beams means that they are only likely to be considered or provided for the highest risk locations.

 

[Narrowgauge725]

I know of at least two UK bridges that have a beam before the bridge

 

[Nottingham59]

An accelerometer fixed to the bridge could measure if the bridge moved, and give reassurance that the railway could continue operations after a bridge strike before any inspection team gets there.

 

[EyeKay]

The A5 bridge near Hinckley, which is one of the most frequently bashed bridges, has a sacrificial beam in front of it in both directions.

 

[RailwayRookie]

An accelerometer fixed to the bridge could measure if the bridge moved, and give reassurance that the railway could continue operations after a bridge strike before any inspection team gets there.

Another piece of equipment that could possibly fail?
There's already a system in place allowing the railway to continue based on each individual bridges characteristics...

considering the fail-safe need of equipment and the potential for a bridge bash, I'd imagine equipment failures and false positives would provide more job stopping events than the current system