Stringfingerling Posted December 1, 2014 Share Posted December 1, 2014 I'm constructing a road overbridge to span two tracks, based loosely on Rifle Range Bridge, seen on p116 of "The Coast Lines of the Cambrian Railways". I need my version to be skewed, and I am curious to know how the brickwork around the arch would have been done in reality. There are plenty of examples of skewed arch bridges with brick facing round the arches; was it necessary for each brick to be cut to an appropriate angle? Clearly the outward faces of the bricks in the centre of the arch would be at right angles to the surface facing downwards inside the arch, but as you move further and further towards the outer edge of the arch, the angle needed would change progressively. In the case of a bridge constructed with stone blocks I can picture the angles being estimated and cut accordingly, but in the case of a brick faced arch the huge numbers of bricks needing cutting to specific angles would seem daunting. Am I missing something here? I have explored Mill Lane Bridge, Leatherhead on Google Street View, which is a good example, but the distortion of the camera angles makes it hard to fully grasp how this works. Perhaps an expert in bricklaying could enlighten me? Link to post Share on other sites More sharing options...
Nick Holliday Posted December 1, 2014 Share Posted December 1, 2014 I work at Leatherhead, and every time I see the skewed arches of the two railway lines as they cross the River Mole I still find it difficult to grasp how they were built, despite having been in the construction industry for40 years! The main thing to remember is that the brickwork arch would have been built onto temporary centring. This would normally be semi-circular in section, and its long axis would follow the line of whatever was being crossed. The bricks would then be laid in a form of stretcher bond on the falsework, parallel to the main axis. The vertical face of the outside of the arch would follow the line of whatever was going over the arch, and hence be at an angle to the coursing of the underside. I think the treatment of this fascia can vary, often it would be stone, or a different type of brick, suitably toothed to pick up the various courses of the arch, although some examples seem to have managed to use the header end of the arched bricks. What must be remembered is that at the time most of these bridges were built, brickmaking wasn't the vast corporate business it is now, and the making of special bricks, and special specials, such as a skewed bridge might require, was all part of the process, and easily incorporated within the production cycle - just think of all those lovely polychromatic brick buildings from Victorian and Edwardian days, with rubbed arches, fancy dentils and other features now extremely rare in new construction. Often brickworks were set up near to major railway projects just to meet the immediate demand, and all the bricks would be effectively hand-made. The other factor is that the bricklayers then were probably more proficient at cutting bricks using the trowel or a cold chisel, producing, usually, very neat results, such as might be needed where the courses run into the vertical abutment walls, at the springing point. If that doesn't help, I can always pop out and take some more photos of the Mill Lane bridge for you! Link to post Share on other sites More sharing options...
Porcy Mane Posted December 1, 2014 Share Posted December 1, 2014 The Images on the Wiki page may be helpful. http://en.wikipedia.org/wiki/Skew_arch Can't be as complex as this one though... (Which just happens to be next to a pub called The Skew Bridge). http://en.wikipedia.org/wiki/Southdown_Road_Skew_Bridge Sticking "Skew""Arch" into the search facility in Flickr brings up plenty of images. e.g. https://www.flickr.com/photos/phill_dvsn/5082352426/in/photolist-8K7oiY-k7GqCU-rAyRe-7Pa3AA-8K7qUh-nERbhZ-aiZt1n-bjXZC9-5hkti7-5te1ZJ-oziRxk-fGYAWF-cVZKUG-oi64uM-oznxwA-8oBc54-7DJtdr-e7adg8-8bZz3S-bDGLrM-c1Svsq-9NVPQg-6eUtze-4KFhx4-cVZKGY-dhUL2v-9knqiC-9kkZqC-bjXZDJ-btkjVp-awSZ2e-5XyDE2-5MBUgJ-aZEb3P-8L81TN-8Ka1NR-awSYJ6-dkzyPY-awVHSw-awSXGa-awT1aF-awSZQi-awVGW1-awSZiV-awSYqg-awVFEs-awVFpY-78dVCf-q9YGvT-9KGAhz Guess what I'm helping to build... Porcy Link to post Share on other sites More sharing options...
Stringfingerling Posted December 1, 2014 Author Share Posted December 1, 2014 Thank you both so much for these replies! Oddly fascinating, and a challenge to my spatial lobes trying to visualise the different planes involved. I think my model will be much easier to build than the real ones. Link to post Share on other sites More sharing options...
Swindon 123 Posted December 1, 2014 Share Posted December 1, 2014 I have recently scanned these photos I took back at the end of March 2005 of the road overbridge on the A480 just out of Hereford where it crossed the Hereford-Hay-Brecon railway, shortly before it was demolished during road improvements. They may be of use to yourself or any one else. Paul J. Link to post Share on other sites More sharing options...
Stringfingerling Posted December 1, 2014 Author Share Posted December 1, 2014 Thanks very much. Link to post Share on other sites More sharing options...
Rivercider Posted December 1, 2014 Share Posted December 1, 2014 Here is one from the Cheddar Valley Line, built by the Bristol and Exeter Railway, pictured on an enjoyable walk along the route from Sandford to Cheddar earlier this year, This bridge is in Winscombe 13/9/2014 edited to add photos ! cheers Link to post Share on other sites More sharing options...
Bristol_Rich Posted December 2, 2014 Share Posted December 2, 2014 This previous thread may help or give you some ideas... http://www.rmweb.co.uk/community/index.php?/topic/85482-skewd-stonebrick-arched-bridges-minimum-angle/ Page 198 of this link may also help... http://books.google.co.uk/books?id=gZtB-RLzTw8C&pg=PA211&lpg=PA211&dq=skew+arch+angle&source=bl&ots=FoBsy70JE7&sig=YHteUTfOwuV8ouPhEXedAq2xslE&hl=en&sa=X&ei=Y21nU4PyOoKMOM38gIgM&ved=0CGAQ6AEwBg#v=onepage&q&f=false Link to post Share on other sites More sharing options...
jonhall Posted December 2, 2014 Share Posted December 2, 2014 Looking on streetview at the double skew bridge at Thames Ditton station might also be worthwhile, but I've no idea how they built it like that. Jon Link to post Share on other sites More sharing options...
RMweb Gold unravelled Posted December 2, 2014 RMweb Gold Share Posted December 2, 2014 These are a few pictures of repaired and original brick arches. The repair has been made with standard rectangular bricks while the original must have shaped bricks to produce the flush appearance. The bridge is over Bolina Rd, South London This nearby bridge is a shallower skew, and use of standard bricks has produced slightly less stepping. Surrey Canal Road This shows where the bridge was widened, and that the brickwork has been laid at a different angle for the extension. Dave Link to post Share on other sites More sharing options...
Stringfingerling Posted December 2, 2014 Author Share Posted December 2, 2014 These are a few pictures of repaired and original brick arches. The repair has been made with standard rectangular bricks while the original must have shaped bricks to produce the flush appearance. The bridge is over Bolina Rd, South London RIMG0617-001.JPG RIMG0620-001.JPG RIMG0629-001.JPG This nearby bridge is a shallower skew, and use of standard bricks has produced slightly less stepping. Surrey Canal Road RIMG0547-001.JPG This shows where the bridge was widened, and that the brickwork has been laid at a different angle for the extension. RIMG0557.JPG Dave That's really interesting to me, as it helps me to visualise the orientation of the bricks. Thanks! Link to post Share on other sites More sharing options...
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