Photo-a-Day (Friday, 22nd June, 2012)
Sennicar Bridge (Bridge 61)
Photo: Harry Cunliffe (Panasonic DMC-FZ38)
Brilliant photo Harry with reflections of the narrowboat and trees, bridge and `perfect` sky with cumulus clouds.
Wonder why the bridge is slightlty arched? Is it for strength or clearance of water traffic?
Put `bridge 61 leeds and liverpol canal` on Google to find several photo`s of this bridge.
Fantastic picture,great composition .One of the nicest walks canal in Wigan ,New Springs bridge-Crawford Arms(Bridge 63).
At a pleased pace aprox.,an hour,this bridge
roughly halfway .
Nice shot Harry. Nice reflection - and the bit of red makes the shot for me.
The bridge looks very nice now, but I wish they would start doing up the Seven Star bridge on Wallgate because that in worse shape than all of them.
I feel proud to live in Wigan when I see scenes like this.
Ernest, the bridge is arched for both the reasons you suggest. It's quite old - made of cast-iron sections - and will probably have been built in a similar fashion to the stone bridges on the canal - over a timber former. The arch is probably not technically necessary to achieve the desired strength for the traffic for which it was built, but they tended to replicate traditional building methods when using the new-fangled technology of building in cast-iron - so, like the stone bridges, it was built with an arch.
It may be noted that the stonework of the abutments is of two different types, that the bridge itself sits proud of the parapets, and that the stones on which the bridge sits do not line up with their neighbours... and the mortar around them has been renewed.
All this suggests two things: firstly, that there may have been a stone bridge here originally, but that it sank because of mining subsidence (which we discussed at length back in April concerning the Rowing Club bridge). It may indeed have collapsed, or have been so difficult to deal with, and future subsidence was predicted, that it was demolished - and replaced with this iron bridge. Then, secondly, subsidence did occur - and the iron bridge was simply jacked up on either side, and new stones inserted to give it the height required for boats to pass beneath.
Lovely pic, too, Harry.
I remember the canals when the only thing that lived in them where leeches.Harry's photo illustrates what a thing of beauty they are now.
How very different to the pictures of old Wigan - (Stuff - Picture Post 1939- page 7.) which include a photo of trenches being dug near the top of Great George St, Wallate. These trenches were supposedly to be covered with earth and sown with grass for playgrounds. From what I can remember, they were mainly covered with building rubble but were still used as playgrounds by the local children
it is a lovely experience to sail a narrow boat along this canal. The only sadness we had was that we were advised not to moore for the night near the Pier, it was too dangerous.
Thanks Rev David - I knew you would come up with the `goods`!!. I suspected the replication of traditional building methods.
You haven`t replied to my comment on P-a-D 19th June`12 at 23:40 when I asked you for present position of St.Catherine`s spire re-build.
Thanks all, the next bridge down leading to Haigh Hall has also just been finished, another nice job but already the yobs have been busy scratching the new paintwork.
Thanks for the info Rev. H.
The two bridges are made of steel ,not iron ,or so the welders told me.
Cast iron, as opposed to wrought iron, is a form of steel, I believe... according to Wikipedia.
Ernest, with all the toings and froings associated with my retirement, removals, etc., I've yet to catch up with events at St Cath's. Should be able to get over there again next week.
Where are you now Rev.. do you still live in Wigan. Hope you are enjoying retirement and its nice to hear from you.
Cast iron is not normally regarded as a form of steel. Cast Iron has large amounts of carbon (relatively speaking) compared with a normal steel. The large amount of carbon, in the form of graphite, makes cast iron weak in compression but strong in tension. Cast Iron bridges need an arch form to keep most of the structure in compression under its own weight and the loads carried by the bridge (this also applies to stone). Wrought iron has very little carbon, which make it fairly soft but can carry tension. A steel has a little more carbon than wrought iron which makes it "very strong" in tension and compression (steels usually have small amounts of other elements to improve structural properties.)
Hello Neil,I`ve looked at Wikipedia which gives all the info on cast iron and steel. When I first looked at this photo I would say this bridge is made from steel and was surprised when Rev David said it`s cast iron. Ron D then said it`s made of steel.
Being a retired mechanical engineer I never thought that cast iron was a form of steel, as we treated them separately.
Photo on ;_
shows the rivetted plates and thus this bridge is definitely made of steel
Mick, to see a photo of Seven Stars bridge refer:-
It states that the seven stars in the name refer to those in the plough constellation.
A correction to my last (late-night) post. Cast iron is weak in tension and strong in compression. Yes Ernest, any mechanical/structural engineer would need to treat steel and cast iron separately or be in real trouble. The reference to "welding" and the presence of rivets both point to a steel construction, as cast iron is extremely difficult to weld and fixing of rivets is difficult due to the brittle nature of cast iron. Cast iron sections would be bolted together, when the "jointing forces" can be applied smoothly at assembly. Even then, extra thickening of the cast iron in the area of the bolts may be required to reduce local stress concentrations induced by assembly process. Aren't we all glad of the development of steel! Wikipediea may be using the word "steel" as a synonym of iron-carbon alloy/mixture which would then include wrought-iron/mild steel/high carbon steel/cast-iron.
OK Neil, may i enquire what you do/did for a living?