Bridge lifting

[CdBrux]

An alternative to knocking down and rebuilding bridges, or track lowering, has been trialled. If it works then the time the lines need to be closed is much reduced so a cost reduction thanks to the rail lines remaining open much longer. It would be interesting to know the cost implications for the bridge itself when not counting the cost of closing the lines.

http://www.railwaygazette.com/news/.../view/bridge-lift-to-increase-clearances.html

some quotes from the article:

The ElevArch technique has been developed by Freyssinet under the RSSB-sponsored ‘Avoidance of Bridge Reconstruction’ competition. This was launched in 2014 to find cost-effective ways of increasing clearances under fixed structures to accommodate overhead electrification. According to the safety and standards body, around 500 masonry arch bridges in the UK need to be raised or rebuilt as part of Network Rail’s electrification programme.

....

The patented technique involves cutting the arch free from its abutments and wing walls so it can be jacked up to increase clearances. According to Freyssinet, ‘the sequence of operations is key to maintaining the all-important thrust line’. A horizontal saw cut is made through each abutment, just below the arch springing, and five holes cored horizontally into each abutment. Vertical lifting jacks are inserted into the holes to support the weight of the bridge.

.....

Whereas a full bridge reconstruction or track lowering can require the railway to be closed for several days, Freyssinet believes that ElevArch could reduce this to a matter of hours, with many of the preparatory and completion tasks taking place behind protective barriers while the line is operational.

 

[najaB]

Very interesting - as they say the key is controlling the lateral thrust. Would be nice to see more photos of the slip joint that they mention.

 

[The Planner]

How close to the running railway would they be when this is going on?

 

[30907]

How close to the running railway would they be when this is going on?

looking at the demo pix confirms my instinct that it needs a complete possession

 

[najaB]

looking at the demo pix confirms my instinct that it needs a complete possession

The actual lift would require a possession, but much of the prep work could be done without needing one, depending on access.

 

[The Planner]

But it still depends on how close they think they can work to a running railway.

 

[najaB]

But it still depends on how close they think they can work to a running railway.

Indeed. Hence why it depends on access - some bridge abutments are quite far from the tracks, others a lot closer.

 

[Tio Terry]

The actual lift would require a possession, but much of the prep work could be done without needing one, depending on access.

How long would the road need to be closed? It's great that this technology can be developed and used to reduce significantly the costs of providing adequate clearances but a sudden, say, 500mm step rise in the roadway would be likely to cause a few problems to road and pathway users and, of course, many bridges also have other services in the roadways like telephony, water, gas and electrical services which would need to be catered for.

 

[najaB]

How long would the road need to be closed? It's great that this technology can be developed and used to reduce significantly the costs of providing adequate clearances but a sudden, say, 500mm step rise in the roadway would be likely to cause a few problems to road and pathway users and, of course, many bridges also have other services in the roadways like telephony, water, gas and electrical services which would need to be catered for.

I would imagine that the road closure would be of similar duration as with conventional methods.

 

[pdeaves]

If it's the bridge lift method I think it is, then the actual lift requires a full possession, not least because of the temporary rods used to tie the two sides of the bridge together.

 

[najaB]

If it's the bridge lift method I think it is...

There's a full description - along with pictures - on page linked to in the OP.

 

[edwin_m]

Longer article:

http://www.railengineer.uk/2016/08/...ds-first-elevarch-masonry-arch-jacking-trial/

 

[rebmcr]

The Merseyrail Loop had its ceiling re-done from behind barriers, with trains passing underneath the workers and plant.

 

[edwin_m]

The Merseyrail Loop had its ceiling re-done from behind barriers, with trains passing underneath the workers and plant.

Not the Loop, the old tunnel southwards from Liverpool Central. The tracks have been lowered to form part of the Link, so there is plenty of headroom to insert a deck above them. This is also featured in the Rail Engineer magazine.