Highlandman Posted September 26, 2013 Share Posted September 26, 2013 Hi everyone, I wonder if anyone can help me find out how a plate girder bridge was constructed across a cutting on a slope. Everything I have looked at, so far, on RMweb and in the reference books I have, show or write about bridges on the flat. My layout Salcombe Harbour is based in South Devon and I am trying to put a lane along the upper slopes of a hill and then turn down to cross the railway and on round the corner to the harbour. Would the bridge be constructed as above, with the road levelling out across the bridge and then continuing down the slope. Making both piers the same height but putting the upper road in a gradually deepening cutting to cross on the horizontal. Or would they have built the top of the piers with an angle to match the slope as per the top example. Or would they have made each pier a different height with horizontal tops and have the girder section slope down but have the end sections horizontal to rest on the piers as per the lower example and highlighted in dark pencil. The more I look into it flat seems the most common but I'm sure I've seen examples of the inclined girder bridge, especially across single track branches. If anyone can help throw some light on this a would be very grateful. Apologies for the rough sketches. Many thanks Andy Edited to make sure piers are vertical in pictures, many thanks Glorious NSE for pointing that out. Link to post Share on other sites More sharing options...
Glorious NSE Posted September 26, 2013 Share Posted September 26, 2013 If it helps, Saltash has an example of a 'sloped' plate girder bridge - to my eye the middle example best matches that particular one. Link to post Share on other sites More sharing options...
BG John Posted September 26, 2013 Share Posted September 26, 2013 Is Llandysul any help? http://www.disused-stations.org.uk/l/llandyssul/index.shtml Link to post Share on other sites More sharing options...
Campaman Posted September 26, 2013 Share Posted September 26, 2013 As Llandsysul, the piers would be vertical so that the loads are carried straight down, if they were at the angle of the slope I would have though that there would be a tendency to collapse, a bit like falling dominoes. Link to post Share on other sites More sharing options...
Glorious NSE Posted September 26, 2013 Share Posted September 26, 2013 I was presuming that's just the angle the drawings have been scanned at, and not a suggestion that the whole world (bridge, abutments, track and grade!) would be at an odd angle. Link to post Share on other sites More sharing options...
Campaman Posted September 26, 2013 Share Posted September 26, 2013 Yeah I here what you are saying, I think a combination of the second two designs would be correct as they are basically the same thing, the main thing is that the piers are vertical with the bridge deck following the grade of the slope. Link to post Share on other sites More sharing options...
Edwin_m Posted September 26, 2013 Share Posted September 26, 2013 There's one at Diggle that is an inspiration for something I have modelled, which looks like the second example assuming the piers are vertical. I realise this isn't GWR! Link to post Share on other sites More sharing options...
28XX Posted September 26, 2013 Share Posted September 26, 2013 In grand style, the Lickey Incline crosses the A448 at 1:37 (as any skoolboy knos). The road is cambered due to a slight left hand curve and is rising in this view towards Redditch, so very little of this structure is plumb or level. Link to post Share on other sites More sharing options...
Highlandman Posted September 26, 2013 Author Share Posted September 26, 2013 Many thanks to those that have replied so far. I have corrected the drawing verticals, which, as Campaman said, were created by an incorrectly scanned picture. Funnily enough Glorious NSE, I looked at Saltash but it's very difficult to tell from Google Earth or Maps how the bridge is constructed. I'll have another look and also try and visit when I am next in Devon. BG John Is Llandysul any help? http://www.disused-s...sul/index.shtml Thanks for this BG John. The picture is quite clear and it was one that never appeared in any Google search I did, no matter what words and terms I used for the search. Edwin_m There's one at Diggle that is an inspiration for something I have modelled, which looks like the second example assuming the piers are vertical. I realise this isn't GWR! Many thanks for that. I will definitely have a look at that one. I can also see I am going to have to try and get L.V. Woods book Bridges for Modellers. It's Scaleforum this weekend in Aylesbury i'll see if they might have one there. Meanwhile if anyone has further examples or ideas, or has built a model I would be very interested in hearing about it. Once again many thanks for your help. Andy Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted September 26, 2013 RMweb Gold Share Posted September 26, 2013 Here's the Saltash one, taken in July 2011 and clearly in need of some TLC (yes, that is a hole you can see) - Link to post Share on other sites More sharing options...
Edwin_m Posted September 26, 2013 Share Posted September 26, 2013 Here's the Saltash one, taken in July 2011 and clearly in need of some TLC (yes, that is a hole you can see) - DSCF3475.jpg Unless it's an optical illusion this is yet another variant - are the flanges (?) vertical or perpendicular to the beam? Link to post Share on other sites More sharing options...
Armchair Modeller Posted September 26, 2013 Share Posted September 26, 2013 Look for photos of Bargoed station - this used to have a girder at quite an angle at the south end of the station http://www.britishrailwayphotographs.com/collection.asp?folder=stations and others Link to post Share on other sites More sharing options...
Flymo748 Posted September 27, 2013 Share Posted September 27, 2013 I can also see I am going to have to try and get L.V. Woods book Bridges for Modellers. It's Scaleforum this weekend in Aylesbury i'll see if they might have one there. Meanwhile if anyone has further examples or ideas, or has built a model I would be very interested in hearing about it. You may also be interested in the new book from the Scalefour Society: "A Modeller’s Guide to Civil Engineering Structures by John A. Smith THE SOCIETY is pleased to announce their latest book, which should be available for sale at Scaleforum later this month. This book is a first; it is published as a CD, readable on your computer screen, which allows for a large and detailed book to be made available at an affordable cost. Our model railways have one thing in common whether they are steam-era historical layouts or are up-to-date systems running the latest traction technology. That one factor is the civil engineering works that are under, over and either side of our trackwork. In this book, the author addresses the basics of civil engineering that can be encountered on British railways and through a series of diagrams outlines the basics of design considerations as well as illustrating the various styles of bridges and other structures. As well as chapters covering a comprehensive range of structures, bonus files are included that feature some prototype and model photographs by the well-known modeller, Richard Chown and some photographs of prototype structures from Mark Tatlow. This disk-based book is simple to use and allows you access to a wide range of exceptionally useful information for the modeller working in any scale or gauge. Price per disc is £7.00" Review copies have been sent to the various magazines, although other than the current Rail Express I haven't seen any published. If you're visiting Scaleforum, come over to the Society Stand and have a chat about the contents of the book... Cheers Paul Willis Scalefour Society Deputy Chairman Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted September 27, 2013 RMweb Gold Share Posted September 27, 2013 Unless it's an optical illusion this is yet another variant - are the flanges (?) vertical or perpendicular to the beam? I think the problem (optically) is that the two lots of 'upright' flanges don't look parallel to each other - and my angle of view (from the Down platform) doesn't help either. If/when I get back down there I'll try a pic from the Up platform and from the road as well. Link to post Share on other sites More sharing options...
rovex Posted September 27, 2013 Share Posted September 27, 2013 I can also see I am going to have to try and get L.V. Woods book Bridges for Modellers. It's Scaleforum this weekend in Aylesbury i'll see if they might have one there. Meanwhile if anyone has further examples or ideas, or has built a model I would be very interested in hearing about it. Andy Page 111 of his book shows a girder bridge on a "considerable angle" apparently near Teignmouth, copyright prevents me posting an image and I can'y find the original on google earth - sorry Link to post Share on other sites More sharing options...
Rivercider Posted September 27, 2013 Share Posted September 27, 2013 My last post seems to have disappeared into the ether...... at Teignmouth there are several sloping bridges in the station area including the high one which features in many photographs, I think these are of GWR build, probably date from 1895 when the line was doubled here and the station rebuilt, edit, here is an arty shot that shows the location of some of them, though no worthwhile detail Teignmouth station, looking towards Newton Abbot, taken 1/3/2011 cheers 2nd edit here is one of the bridges west of Teignmouth, albeit a footbridge 47301 heads west on a summer saturday, 21/7/84 Link to post Share on other sites More sharing options...
Portchullin Tatty Posted September 30, 2013 Share Posted September 30, 2013 Andy It is perfectly acceptable to have a steel or iron girder bridge on an incline. For what it is worth you have to have the sliding bearing at the top; but I am assuming you are not too excited about this as it will be invisible! Quite how the abutments would be dealt with will depend on the nature of the situation; particularly the incline that you are putting on the road (I assume you are doing an overbridge?). The pictures below show Divie Viaduct at Dunphail which formerly had the Highland's original mainline go over it at (I think) 1:50. You can see that the main parapet is much lower at the north end than the south; as the deck of the bridge has droped the couple of feet difference and they kept the stonework courses level. north end parapet south end parapet; showing the relative drop Alternatively; as the picture of the footbridge at Teignmouth from Rivercider shows you get the capping stones on the pier level and then the parapets to the approach abutments following the slope of the road. As a final alternative, particularly for steep slopes, you get both the parapets and the capping stones at an incline as per the Llandysul pictures from BG John. Link to post Share on other sites More sharing options...
Highlandman Posted October 1, 2013 Author Share Posted October 1, 2013 Here's the Saltash one, taken in July 2011 and clearly in need of some TLC (yes, that is a hole you can see) - DSCF3475.jpg Many thanks for the picture Mike. It appears to show the ledge that the bridge sits on to be level on the horizontal plane, with enough height to hold the stone or concrete pads the bridge sits on and the bridge itself so that the deck is level with the road surface. The great thing this picture shows is the retaining wall which I could incorporate into the build as I assume the track starts to rise out of the valley within the fiddle yard. You may also be interested in the new book from the Scalefour Society: "A Modeller’s Guide to Civil Engineering Structures by John A. Smith THE SOCIETY is pleased to announce their latest book, which should be available for sale at Scaleforum later this month. This book is a first; it is published as a CD, readable on your computer screen, which allows for a large and detailed book to be made available at an affordable cost. Our model railways have one thing in common whether they are steam-era historical layouts or are up-to-date systems running the latest traction technology. That one factor is the civil engineering works that are under, over and either side of our trackwork. In this book, the author addresses the basics of civil engineering that can be encountered on British railways and through a series of diagrams outlines the basics of design considerations as well as illustrating the various styles of bridges and other structures. As well as chapters covering a comprehensive range of structures, bonus files are included that feature some prototype and model photographs by the well-known modeller, Richard Chown and some photographs of prototype structures from Mark Tatlow. This disk-based book is simple to use and allows you access to a wide range of exceptionally useful information for the modeller working in any scale or gauge. Price per disc is £7.00" Review copies have been sent to the various magazines, although other than the current Rail Express I haven't seen any published. If you're visiting Scaleforum, come over to the Society Stand and have a chat about the contents of the book... Cheers Paul Willis Scalefour Society Deputy Chairman Thank you for this information Paul and it was good to meet you at Scaleforum. I have had a look at the disk and there is plenty of information available for the budding civil engineer. I will need to look at it in more detail, but what I have already seen has been of some help. For £7 I can recommend adding it to your library. Page 111 of his book shows a girder bridge on a "considerable angle" apparently near Teignmouth, copyright prevents me posting an image and I can'y find the original on google earth - sorry My last post seems to have disappeared into the ether...... at Teignmouth there are several sloping bridges in the station area including the high one which features in many photographs, I think these are of GWR build, probably date from 1895 when the line was doubled here and the station rebuilt, edit, here is an arty shot that shows the location of some of them, though no worthwhile detail IMG_3588.JPG Teignmouth station, looking towards Newton Abbot, taken 1/3/2011 cheers 2nd edit here is one of the bridges west of Teignmouth, albeit a footbridge scan0030.jpg 47301 heads west on a summer saturday, 21/7/84 Thank you rovex for that information. I did know that Teignmouth had a few inclined bridges but could not find any images of any other than the regular lattice girder you can see from the seawall. It sounds as though I really do need to add that book to my library. The picture of the footbridge over the cutting from Rivercider is useful in that it shows upright abutments with horizontal capping stones. Again it seems to show a horizontal ledge for the inclinded deck to sit on. MAny thanks for everyones help so far. It is very much appreciated. Link to post Share on other sites More sharing options...
Highlandman Posted October 1, 2013 Author Share Posted October 1, 2013 Andy It is perfectly acceptable to have a steel or iron girder bridge on an incline. For what it is worth you have to have the sliding bearing at the top; but I am assuming you are not too excited about this as it will be invisible! Quite how the abutments would be dealt with will depend on the nature of the situation; particularly the incline that you are putting on the road (I assume you are doing an overbridge?). The pictures below show Divie Viaduct at Dunphail which formerly had the Highland's original mainline go over it at (I think) 1:50. You can see that the main parapet is much lower at the north end than the south; as the deck of the bridge has droped the couple of feet difference and they kept the stonework courses level. _DSC0241compress.JPG north end parapet _DSC0245compress.JPG south end parapet; showing the relative drop Alternatively; as the picture of the footbridge at Teignmouth from Rivercider shows you get the capping stones on the pier level and then the parapets to the approach abutments following the slope of the road. As a final alternative, particularly for steep slopes, you get both the parapets and the capping stones at an incline as per the Llandysul pictures from BG John. Good to hear from you Mark. Many thanks for that info. It looks as though I have a lot to think about. I might have to come up with a sketch just to see what it might look like and give me some idea how to go about it. I've just had a lokk at the viaduct on Google Earth as it wasn't one I was familiar with in Scotland. Pretty impressive and some nice stonework there as well. Link to post Share on other sites More sharing options...
Highlandman Posted October 1, 2013 Author Share Posted October 1, 2013 I'm not the best of artists but this is a rough sketch of what I have in mind. I'll see how it goes now I know the fixed point is at the bottom of the bridge an the sliding plate is at the top. Link to post Share on other sites More sharing options...
jastrain Posted November 11, 2013 Share Posted November 11, 2013 Hello I've only just read your query and have attached a sketch which may be of some assistance to you. Jastrain.sloping bridge girder.doc Link to post Share on other sites More sharing options...
Highlandman Posted November 12, 2013 Author Share Posted November 12, 2013 Hello I've only just read your query and have attached a sketch which may be of some assistance to you. Jastrain.sloping bridge girder.doc Many thanks for that Jastrain. It's a useful bit of information to add to that I have already received. Link to post Share on other sites More sharing options...
RMweb Gold simonmcp Posted November 13, 2013 RMweb Gold Share Posted November 13, 2013 Hi Higlandman, Don't forget that the girders have to sit on a ledge or concrete plate at each end. Like this: http://www.thewhistlepost.com/forums/attachments/o-scale/2498d1302137717-l-crr-plate-girder-bridge-img_0271.jpg or this :http://www.thewhistlepost.com/forums/attachments/o-scale/2497d1302137717-l-crr-plate-girder-bridge-bridge-shoe.jpg which also shows what is called the shoe. or this: http://www.johnweeks.com/river_mississippi/pics03/mn23new62.jpg which shows it at the grey painted end. or this in model form: http://www.valleymodeltrains.com/catalog/images/151/151-7923.jpg Simon Link to post Share on other sites More sharing options...
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