Vertical lifting bridges - why or why not?

[magpie patrick]

I've become involved in a discussion about whether to build a moveable bridge on a canal restoration project rather than a fixed bridge - in this case the advantage of a moveable bridge is less ground load and less land take (utility services being a major influence in this) - in reviewing options we looked at others elsewhere for inspiration and among them is the vertical lift bridge, as opposed to the bascule bridge - an example below

 

 

This is Locomotive Bridge, Huddersfield, with acknowledgements to Martin Clark and Pennine Waterways. Cables pull the bridge vertically. When asked to consider the pros and cons of such a bridge I'm stumped - there is, as far as I know, no documented design considerations, and there are so few that I can't really work out the reasoning, a sample of one (that I used once, many years ago) doesn't really tell me what the advantages of this design are.

 

So does anyone have any thoughts on the pros and cons of vertical lifting ? And are there any others on the canal system? I'm aware of them on much bigger waterways where presumably the size of the span is a factor, but not really on waterways the size of our typical canals, where lift bridges are nearly all the bascule type. 

[BuckbyLocks]

There are lots of them ib Belgium near Charleroix and on the Roubaix Canal. All hydraulic I think. Cons are that the pistons must move together or the system jams and cannot be easily fixed, but the ones I have encountered have all been very efficient, although Bridge Keeper operated from slightly remote cabins.

[billh]

Rochdale Canal ,Grimshaw Lane, Chadderton. A modern hydraulic lift system. I can't remember what the old bridge was like, it's about 50 years since I crossed it. The modern system does not seem to be very reliable- fancy electrical control system and miles of hydraulic pipes and fittings ready to leak at a moments notice.

[David Mack]

There is one across the entrance to the canal arm at the Black Country Living Museum, formerly at Lloyds Proving House, Netherton.

 

https://www.geograph.org.uk/stuff/list.php?title=Lifting+Bridge+&gridref=SO9491

 

The three British examples quoted so far are all functionally different. Locomotive Bridge in Huddersfield is lifted by central chains, the BCLM example by chains at each corner, and the Rochdale example has hydraulic cylinders below the deck at each corner.

39 minutes ago, magpie patrick said:

So does anyone have any thoughts on the pros and cons of vertical lifting ?

Two of the three examples have a bulky overhead structure. Fine for a historic artefact, but would you want to build a new one? The underlifted Grimshaw Lane version looks neater (when down) but hasn't proved particularly reliable. I imagine any loss of synchronisation of the lifting cylinders could cause the whole thing to jam.

 

Why a lifting bridge anyway? Surely a swing bridge is less intrusive, more reliable, well established technology and probably no more expensive.

Edited June 7 by David Mack

[magpie patrick]

15 minutes ago, David Mack said:

 

Why a lifting bridge anyway? Surely a swing bridge is less intrusive, more reliable, well established technology and probably no more expensive.

 

At larger sizes I'd agree, indeed at very large sizes swing is undoubtedly better. But at narrow canal size, where a bridge can easily be hand operated, it's no contest. The main issue is that without jacks a swing bridge takes all the weight through the bearings and will tend to hog, a lift bridge doesn't do this. A manual swing bridge can have jacks, but it complicates operation, a lift bridge doesn't need them. 

 

Reading through stoppages and complaints about difficult bridges on the canal system, I'd say swing bridges give far more trouble. 

[Jonny P]

The downside of a vertical lift bridge is that it requires more work to be done to lift the full deck as opposed to half of it with a bascule bridge. That may be a very simple reason why bascule bridges were historically preferred to vertical lift bridges. It may not apply so much these days.

 

An advantage of a vertical lift bridge may be in the simplicity of the bearing design because you don’t have to consider how the deck will bear when being lifted and how the load will transfer from the ‘static’ bearings to whatever supports the deck when being lifted, and vice versa. I’m not sure how much of an issue this is with a bascule bridge but larger swing bridges have some complexity due to the fact that the turntable isn’t normally able to bear vehicle loading, so swing bridges with full road loading requirements tend to have a form of retractable bearings.

 

ETA - you’ve partly covered the above in your post while I was writing this.

Edited June 7 by Jonny P

[dmr]

57 minutes ago, billh said:

Rochdale Canal ,Grimshaw Lane, Chadderton. A modern hydraulic lift system. I can't remember what the old bridge was like, it's about 50 years since I crossed it. The modern system does not seem to be very reliable- fancy electrical control system and miles of hydraulic pipes and fittings ready to leak at a moments notice.

[TheBiscuits]

The Rochdale one has the advantage that cars do stop for it.

 

For some odd reason a couple of feet thickness of concrete and steel lifting up in front of them gets more respect than a plastic red and white tube slowly descending ...

[magnetman]

A vertical lifting bridge means full width headroom. I seem to recall that someone was badly injured or possibly killed at Aldermaston lift bridge on the K&A. 

 

If there is a choice fo do either there could be an elfin safety argument in favour of a vertical lift in terms of safety of people using the waterway.

 

I remember a vertical lift bridge in Paris which was impressive on hydraulics but I suppose it is a lot of additional equipment compared with a bascule or swing bridge. 

 

I wonder if anyone ever made a folding bridge where the deck lowers down into the water rather than lifting above. 

 

 

[David Mack]

1 hour ago, magpie patrick said:

But at narrow canal size, where a bridge can easily be hand operated, it's no contest. The main issue is that without jacks a swing bridge takes all the weight through the bearings and will tend to hog, a lift bridge doesn't do this. A manual swing bridge can have jacks, but it complicates operation, a lift bridge doesn't need them. 

Is this for a farm track or a public road? If there is an existing uninterrupted road at present I would have thought the highway authority would want to see a properly engineered automatically operated bridge, whether lifting or swing, rather than a manually operated bridge which could be left in the open (or partly open) position.

I agree that a swing bridge without jacks will leave weight on the main swivel bearing, which will get damaged under road traffic loading, and the bridge deck will 'bounce'. But then a lift bridge lightly enough balanced to be operated manually will also tend to bounce under heavy vehicles.

[magpie patrick]

18 minutes ago, David Mack said:

Is this for a farm track or a public road? 

 

Right of access to third party land (and even that's disputed but we need a bridge for other reasons e.g. maintenance and towpath access) - public road loading first choice is  for a swing bridge with jacks (edited to add - powered swing bridge) - it's not the absolute axle load but the frequency that does the damage. 

 

Last scheme I looked at on a public road though the gradient wouldn't work with a swing bridge! I am also looking at one in south Wales where it will have to swing as its half under a railway bridge - no room to lift

 

I can see it might be worth locking a lift bridge down though 

[ditchcrawler]

1 hour ago, dmr said:

What about head clearance for road traffic?

[BEngo]

21 minutes ago, magnetman said:

I wonder if anyone ever made a folding bridge where the deck lowers down into the water rather than lifting above. 

Yes.  There is one on the Corinth Canal.  I have been through by water..  The deck does not fold , it just descends vertically into the canal until there is navigable depth above the road. 

 

I have no idea how it deals with silt.

 

As for the original Q, I would think the starting point might be some sort of user spec.  Span, width, traffic details ( land side and water side, site  constraints, etc.  An engineering analysis of the options would  follow.

 

N

[Chris Lowe]

The Wey & Arun have one in store for future use, it came from the GKN factory in Birmingham.

[rogher]

A vertical lift would provide the same clearance across the full width of canal, but a lift bridge might allow a boat with tall chimney or mast through if it revealed enough sky.

If the majority of narrow canal moving bridges is a hinged lift arrangement, there must be good reason for that method over any other.

I assume that simple lift bridges are cheaper and more reliable than other types. 

The frequency of use may be an important factor to consider, also.

[magnetman]

1 minute ago, rogher said:

A vertical lift would provide the same clearance across the full width of canal, but a lift bridge might allow a boat with tall chimney or mast through if it revealed enough sky.

If the majority of narrow canal moving bridges is a hinged lift arrangement, there must be good reason for that method over any other.

I assume that simple lift bridges are cheaper and more reliable than other types. 

The frequency of use may be an important factor to consider, also.

It could also be related to available technology and materials when the canal was constructed. Of course part of the reason for narrow canals was low construction costs so maybe a simple lift bridge was the cheapest way to accommodate land owners without putting in fixed bridges. 

 

 

 

 

[Momac]

The vertical lift bridges shown above are economical on materials and probably also economical on foundations. But they are not very elegant.

But I would say this bridge on the New Junction Canal although requiring more steel are in some respects less complex but certainly  a feature on the landscape. 

[rogher]

15 minutes ago, magnetman said:

It could also be related to available technology and materials when the canal was constructed. Of course part of the reason for narrow canals was low construction costs so maybe a simple lift bridge was the cheapest way to accommodate land owners without putting in fixed bridges. 

 

 

 

 

True, indeed, but a restoration project will probably need to watch the budget.

 

[ditchcrawler]

 

But on a much smaller scale

Edited June 7 by ditchcrawler

[matty40s]

Another from Glasgow

 

[Phoenix_V]

There are a few in France or Belgium but presumably being more expensive than a  normal lift bridge only seem to be used where there is lack of space for the counterbalance here is a modern one near Bruges where they have moved the counterbalance at 90 degrees to the bridge

and here is another modern one on a roundabout in Lille actually 2 one each side of the roundabout but thesehave has a rather large machine room  and the support wall appears to have a large crack in it so probably not one to copy

[magpie patrick]

9 hours ago, ditchcrawler said:

 

But on a much smaller scale

 

I note the video claims 1890s for the rolling bridge idea, but the Oxford Canal bridges roll, and the concept there is presumably a century older. This is just a huge Oxford Canal Bridge!

[pearley]

Centenary Bridge and Lowry Bridge over the Manchester Ship Canal

Edited June 8 by pearley

[Russ T]

Kingsferry Bridge - Isle of Sheppey

[Pluto]

52 minutes ago, magpie patrick said:

 

I note the video claims 1890s for the rolling bridge idea, but the Oxford Canal bridges roll, and the concept there is presumably a century older. This is just a huge Oxford Canal Bridge!

The Schertzer type rolling bridge was introduced towards the end of the 19th century, the large rolling section ensuring that the bridge deck did not interrupt the bridge hole when raised, the deck rolling clear of the passage. Materials and demand affected the design of dock swing bridges, with the moved from cast iron to wrought iron being necessary when the width of boats increased with the introduction of paddle steamers. For small canals, I always liked the old L&LC design which used two concave circular cast iron plates as the bearing, with a spigot to centralise the deck. The plates could crush most stones, making them easy to swing, but the increasing weight of road traffic resulted in cracked plates which could jam. Alas, none survive. The lift bridge at the BCLM was used as a children's swing prior to being moved to the museum. They would swing the counterbalance weights energetically, resulting in the support columns and drive shafting becoming bent. There are lots of problems to be overcome with opening bridges, and I would recommend trying to keel any design as simple as possible.