Bridges on bends

[steelaway]

Can some one explain to me the reason why so many canal bridges are built on a bend?

You can go across country for miles and as soon a the canal goes off around a bend do they put a bridge in !

Good old Brindley is the master of it.

 

Alex

[Chris J W]

A thought that's often gone through my mind, too ...

[Natalie Graham]

It is so people can get from one side of the canal bend to the other.

 

I wonder if the surveyors setting out the line of the canal worked from one point on a road or track to another, so the canal changed direction where it crossed a road and needed a bridge and went reasonably straight in between.

[Boatgypsy]

It is most likely that where possible canals followed property, parish or field boundaries. Bridges were then often placed at a boundary junction. Likewise old rights of way tended to cross fields at their margins or corner to corner. Bridges that accommodate old rights of way were therefore at the corners of fields - even though now the field boundary may have been ploughed up and disappeared.

 

I dare say the landowner could demand the bridge where he wanted it - maybe they were just being bloody minded.

That's my theory anyway!

[PhilR]

Can some one explain to me the reason why so many canal bridges are built on a bend?

You can go across country for miles and as soon a the canal goes off around a bend do they put a bridge in !

Good old Brindley is the master of it.

 

Alex

 

You will probably find that in these cases the road was built first and the canal was aligned (on a bend) to go under the road at 90 degrees. This would mean much simpler bridge construction.

 

Having said that, some of the skew bridges on the Macc Canal are real treasures of masonry skills.

[Guest]

Can some one explain to me the reason why so many canal bridges are built on a bend?

You can go across country for miles and as soon a the canal goes off around a bend do they put a bridge in !

Good old Brindley is the master of it.

 

Alex

 

I think this depends on which canal you are on...

 

we've been on sections and wondered the same ...

 

and we've been on sections where they all come in a straight line and not noticed.... or commented.

 

Possibly you've noticed the ones on bends a bit more because they need more attentionl...

[magpie patrick]

You will probably find that in these cases the road was built first and the canal was aligned (on a bend) to go under the road at 90 degrees. This would mean much simpler bridge construction.

 

Having said that, some of the skew bridges on the Macc Canal are real treasures of masonry skills.

 

Yup, and the Macc was a very late canal, some sixty years after the Bridgwater and the T and M. It's ruler straight in places

 

One reason is act of negligence rather than deliberate fault. The significance of what highway engineers now call "forward visibility" and "stopping distance" was not fully understood. The Peak Forest Canal Company slightly altered their line at one point (north of Hyde Bank Tunnel) to improve this.

 

Several canals (Chesterfield, Oxford, Coventry, T and M) made an awful lot of effort to stay very close to the contour. At Misterton on the Chesterfield the canal makes a sweeping detour to avoid a cutting that would only have been about 3 feet deep. In doing this, and respecting existing rights of way, you build bridges where they arise, not where you would ideally have them

[steelaway]

It is so people can get from one side of the canal bend to the other.

 

I wonder if the surveyors setting out the line of the canal worked from one point on a road or track to another, so the canal changed direction where it crossed a road and needed a bridge and went reasonably straight in between.

 

 

 

All great suggestions although I tend to lean towards this one.

Some then now seem to be simply bridges between fields and could have been placed any where, may well have been well used tracks in the 1790's.

I'll keep it in mind now and see if this theory could be right, although I will be on the Thames and GU for the next couple of months.

Being much later I can't imagine the GU having to abide by the same rules - we'll see.

Thanks guys (& gals) See - I have learned my lesson

 

Alex

[RLWP]

The flaming South Stratford can manage to put a bridge on a bend in the middle of a straight!

 

 

Richard

 

That's what happens when you build a cut on the cheap

[Sue1946]

They were angled just to defy me!

I recently had a superb week with friend on a well known canal.

Friend decided I need to learn to drive thro' bridge 'oles. I hit every one on the first try! (and cried a lot!!) (well some paint work was squandered)(and 'this way' is NO WAY to help a driver now is it? - fgs what is 'this' !!)

I hit several on the 2nd, but they were more like soft sort of bumps.

I can't wait for my next 'try'!

[Dr Bradley]

And why, on these bendiest bridges is there always a weeping willow next.

[Daio]

And why, on these bendiest bridges is there always a weeping willow next.

 

Because they are emoting with Sue1946. Weeping, crying a lot, geddit? Oh FGS

[NB Alnwick]

When I was at school at Welford in the 1950s, we were taught something about the local canals and one of the facts that I remember was that the Canal Company were obliged to put bridges in for public Rights of Way and to enable farmers and landowners to cross the canal - the latter being spaced at intervals of 1/4 mile - so when that canal (the Watford to Foxton section of the GU Leicester Line) was built there were bridges every 1/4 mile at least - some of them were made of wood and many (including all of the wooden ones) no longer exist. With so many bridges, there has to be a likelihood that many will be on or near bends.

 

Although this is off topic, in the summer we used to be taken out for walks along the canal and enjoyed a very practical (and memorable) combined history and geography lesson. What a pity today's children don't get similar lessons - they may then grow up with more respect for our heritage.

[Keeping Up]

I reckon Mr Brindley employed some cheap contractors to put the bridges in place, which they did only approximately because they were dreadful at map reading, and then he came along afterwards and somehow had to build the canal so that it fitted through the bridges.

[alan_fincher]

When I was at school at Welford in the 1950s, we were taught something about the local canals and one of the facts that I remember was that the Canal Company were obliged to put bridges in for public Rights of Way and to enable farmers and landowners to cross the canal - the latter being spaced at intervals of 1/4 mile - so when that canal (the Watford to Foxton section of the GU Leicester Line) was built there were bridges every 1/4 mile at least - some of them were made of wood and many (including all of the wooden ones) no longer exist. With so many bridges, there has to be a likelihood that many will be on or near bends.

Graham,

 

Have you ever been able to find any documentary evidence for such a claim subsequently ?

 

It does sound unlikely that much of the Watford to Foxton section would have had bridges at any interval as close as 1/4 mile, over large amounts of it's length.

 

On many canals where bridges have been removed, there is still strong evidence of their former existence, including narrowing at some of the points involved, or sometimes the raised approaches to them, if they were not lift or swing bridges.

 

I don't recall large number of bridge narrows with no bridges on that summit, and as commercial use of that stretch failed to reach anything like expectations, (think the economic failure of the Foxton Inclined Plane, due to low traffic levels), it seems unlikely that great expense would have been made to widen the cut as small bridges were removed.

 

I'm not disputing many bridges have gone missing on many canals - clearly they have, but that statistic you were taught about that stretch just doesn't sound right to me, particularly as it is one of the stretches most remote from significant civilisation.

 

I'm not saying it's definitely wrong, but I wonder if the claim can be proven ? Many of the educational materials about canals that are about today, for example, have some very strange ideas in them, (he says, donning his Boatman's bowler!).

[Laurence Hogg]

I have always been convinced James Brindley was either drunk, had a serious eyesight problem, was on Belladonna or something that distorts the mind. Why "contour canals" have to follow the contour when only a mile away is where it will take several to get to really beats me, anyone with an ounce of logic would have built an embankment or a bridge (as he likes those - mostly at a bend you know) to get there, even in the relativly flat Black Country the Old main line wanders here and there (often in the past near to many ale houses). Bless him, then came the Jeremy Clarkson of canal building, man Telford, dead straight and throught it! or over it, logical thinking, a shorter time between the ale houses ....

[Keeping Up]

I have always been convinced James Brindley was either drunk, had a serious eyesight problem, was on Belladonna or something that distorts the mind. Why "contour canals" have to follow the contour when only a mile away is where it will take several to get to really beats me, anyone with an ounce of logic would have built an embankment or a bridge (as he likes those - mostly at a bend you know) to get there, even in the relativly flat Black Country the Old main line wanders here and there (often in the past near to many ale houses). Bless him, then came the Jeremy Clarkson of canal building, man Telford, dead straight and throught it! or over it, logical thinking, a shorter time between the ale houses ....

Thinks - was James Brindley being paid by the mile?

[RLWP]

Thinks - was James Brindley being paid by the mile?

 

Thinks - were the directors of canal companies often mine owners. Goodness me, for the BCN, so they were! Funny how the meanderings of that cur made it pass nearer the shareholders businesses...

 

Richard

[magpie patrick]

I have always been convinced James Brindley was either drunk, had a serious eyesight problem, was on Belladonna or something that distorts the mind. Why "contour canals" have to follow the contour when only a mile away is where it will take several to get to really beats me, anyone with an ounce of logic would have built an embankment or a bridge (as he likes those - mostly at a bend you know) to get there, even in the relativly flat Black Country the Old main line wanders here and there (often in the past near to many ale houses). Bless him, then came the Jeremy Clarkson of canal building, man Telford, dead straight and throught it! or over it, logical thinking, a shorter time between the ale houses ....

 

 

Not sure whether tongue in cheek or not, but at wormleighton, the local landowner wasn't happy about locks to a short summit level, as it meant boatmen had reason to stop... So brindley went round

[Cosy Toes]

No, honestly...

You are all so very wrong.

It is of course so that everytime you come to a bridge you meet another boat going the opposite direction and if you look really close you can see them mouthing 'This is MY bridge' whilst accelerating.

Ha ha

[Henhouse]

Why "contour canals" have to follow the contour when only a mile away is where it will take several to get to really beats me, anyone with an ounce of logic would have built an embankment or a bridge (as he likes those - mostly at a bend you know) to get there,

 

 

Because they were virtually all dug by hand. Digging deep cuttings or building lock flights was expensive and time consuming. Embankments could also be prone to subsidence.

 

Working to the contour may involve a longer route, but was more simple and cheaper to construct and operate.

[Theo]

And why, on these bendiest bridges is there always a weeping willow next.

and a boat!

 

bbb

 

Bridge bend boat

[Guest]

Working to the contour may involve a longer route, but was more simple and cheaper to construct and operate.

 

But was it best for the carriers though?? surely the greater distances involved cost the carriers money - hence projects like the shortening of the North Oxford when the technology and funds allowed...

Edited June 28, 2010 by NB No Deadlines

[Machpoint005]

Forward visibility would not have been a problem in the 1790s when a boat was always preceded by a horse!

[Pluto]

There was a rapid development in canal engineering from the 1760s. Early canals, those built prior to 1780, tend to be contour canals, with the engineering avoiding major cuttings and embankments. The 1780s saw a lull in canal construction due to wars affecting the economic situation, with canals built from the 1790s being much more confident from an engineering point of view. The L&LC is a good example, with the early sections being contour canals, while from 1794 the route was changed in East Lancashire to cross much more challenging countryside. There are eight major embankments between Barrowford and Johnsons Hillock, those built first around Burnley taking years to settle and consolidate, putting back the opening of sections of the canal. The design of good embankments only reached some sort of maturity around 1800. Also, the level of the Burnley Pool had to be designed such that the earth excavated near to the valley crossings was sufficient to build the embankments, setting against this the difficulty and expense of the cutting near Rishton.

 

The location of bridges was only settled during construction. A survey for a canal was produced as part of the Bill to be presented to Parliament, and this identified the land owners affected. The majority had to be in favour of the canal before it could obtain an Act. The Act then had clauses which allowed the line to change by perhaps a couple of hundred yards during construction in order to overcome problems, such as the levels for the original survey not being correct. Such deviations increased the number of fields divided by the construction of the canal, and land owners could insist on accommodation bridges to connect such divided fields. It was sometimes cheaper for the canal company to buy the land than to build a bridge. The land actually purchased for a canal could only be legally identified after the canal had been built.

 

Over bridges on early canals were usually a simple arch or swing bridge, and the bridge had to be square on to the canal, sometimes making it difficult for boating if the bridge was on a bend. Skew arch bridges, where the road crosses the canal at an angle, were first used on the Grand Canal in Ireland circa 1794, but were not widely used - or understood technologically - until around 1810. There are skew bridge from this time, such as Eanam Bridge on the L&LC, formed by building a simple arch with triangular additions on either side. This was not a good solution as, for the best load bearing solution, the stonework of a skew arch needs to twist, a bit like a screw thread.

 

So why are bridges sometimes on bends? For a canal following a contour, there will be a bend where the canal crosses a side valley, and roads would often follow valleys as the easiest route up or down a hillside. Consequently, you get canal bridges on bends. Sharp bends can also indicate where the route of a canal has been changed. For example, the sharp bend at Parbold is actually a junction, the mainline of the canal from Liverpool should have continued towards Leyland, the canal up to Wigan being a branch. At Church, also on the L&LC, the canal was originally designed to go further into Accrington, the right angle bend resulting after the route was changed.