Could anyone put me onto a site or article showing how to build a curved trestle bridge? Have got the road bed curved by using the ladder method at an eight foot radius now not sure how to proceed.
tutpc Could anyone put me onto a site or article showing how to build a curved trestle bridge? Have got the road bed curved by using the ladder method at an eight foot radius now not sure how to proceed.
If you have the bridge deck comoplete (as I understand your post), you have the hard part done. Just build a series of timber or post bents and place them under the deck at 6 to 8 inch intervals.
Tom Trigg
Thanks Tom....... I may have not explained myself properly as I was after a through truss bridge type construction either on top or attached to the road bed that I have already made. Have managed to make straight bridges in the past but not a curved one. Would appreciate any input. Thanks.
The "curve" is just a series of straight sections wide enough to support the ends and the middle of the curve's excursions from straight. The longer the straight section the wider is has to be to support the track.
Semper Vaporo
Pkgs.
tutpc Thanks Tom....... I may have not explained myself properly as I was after a through truss bridge type construction either on top or attached to the road bed that I have already made. Have managed to make straight bridges in the past but not a curved one. Would appreciate any input. Thanks.
Truss bridges are built for the economy of materials that this form of construction provides. They rely upon the compression and tension of the bridge members for strength. Truss bridges cannot be built in a curve, by definition they must be straight. A series of truss bridges with one side shorter than the other meeting at a 10~15 degree angle can be assembled on intermediate supports thus supporting your curved rail deck.
You have not said how long your bridge is to be. If your bridge is not too long, say 30 inches (~60 scale feet) you could easly build a sieres of trusses under the rail deck with five or six straight trusses. These trusses would need to be wider than the the curved rail deck with crossmembers and stringers to support the rail deck and properly transfer the load across all the trusses.
In the real world all bridges built on a curve have been of the trestle type (timber or steel). Even then, the spans are straight, allowing the rails to curve.
Tom.... I bow to your superior knowledge and am now at the drawing board working out the degree on the angles.
Thank you and "God Save the Queen"
tutpc - Superior knowledge is only acheivable through multiple failures. In 1996 I was assigned a task of building a bridge to the top of our waterfall by 'She Who Must Be Obeyed'. I assembled the needed information and began my design work to accomplish that task. All the advise at the time said that anything above a four percent grade would not only be non-realistic but very destructive to my equipment. I presented the argument to not build the bridge. SWMBO said "DO IT" and here is the credit card go get at least five of the same thing to climb the hill. When you burn up one, just open the box for the next one and keep on climbing the hill. The bridge was built. The first segment is ground work of 8 ft that raises to 6% grade, then to the fist segment of bridge (13 ft) that averges 13% straight into an "S" curve of 13 1/2 inch radius without a straight transition in between (another "It CANNOT be done") to the final segment of the bridge at 22 ft and a 19% grade. I had anticipated burning through all five trolly sets in the first year. Each year we had an Anniversery Run and the four backups are retreived from their boxes and exercised for the day and returned to the box at the end of the day. It has been 19 years and the orginal trolly set is still making the climb. About 11~12 years ago an LGB Auto Reversing unit was installed with a dedicated power supply so that it runs all day up and down the hill. Just because someone says "It cannot be done" is no reason not to try.
Tom... as told to me when working in a village school in Lesotho, Africa, by a very young boy "better to try and fail than fail to try"
Post a pic if you can I need inspiration.
Alan.
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