Pratt Truss
Pratt Truss
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 Central Valley 1902 150 Pratt Truss Bridge  US $36.31
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 BRASS 162ft PIN CONNECTED PRATT TRUSS BRIDGE F P BLACK US $695.95
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 BRASS 162ft PIN CONNECTED PRATT TRUSS BRIDGE UNPAINTED US $495.95
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Great Deals On Amazon Products
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Atlas O Scale 3-Rail Single Track Pratt Truss Bridge List Price: $159.95 Sale Price: $137.49  |
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With a whopping 40" of realism, Atlas O's latest structure kit is an incredibly detailed model of the ubiquitous Pratt Truss Bridge, a common sight of the railroads of yesterday and today. Based on a Missouri Pacific Railroad prototype, the model is truly representative of a bridge style that fits right at home on any rail line... |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $8.99 |
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14. BRIDGE TENDER ALBERT REEVES (RIGHT) AND YOUTHFUL HELPER (WALLY HALES), HANDLING HUGE 'KEY' TO WIND OPEN THE CENTER SWING SPAN. - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $8.99 |
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11. EASTSIDE SHOWING SWING SPAN - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
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Historic Photo Baltimore & Ohio Railroad Parallel Pratt Thru-Truss Bridge, Limestone, NY Sale Price: $8.99 |
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1. GENERAL VIEW OF BRIDGES - Baltimore & Ohio Railroad, Parallel Pratt Thru-Truss Bridge, Limestone, Cattaraugus County, NY |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $8.99 |
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4. BRIDGE FROM SOUTHEAST - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $16.99 |
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10. STONE FOUNDATION AT NORTH END OF BRIDGE - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $8.99 |
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3. FROM NORTHWEST - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
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Historic Photo Maurice River Pratt Through-Truss Swing Bridge Spanning Maurice River Sale Price: $16.99 |
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6. NORTH END OF BRIDGE - Maurice River Pratt Through-Truss Swing Bridge, Spanning Maurice River, Mauricetown, Cumberland County, NJ |
bridge question?
I want to build a bridge that will provide the best weight to mass ratio.
A brick will be placed on the very top of the bridge (not on the bottom platform) and a machine will apply certain pressure to the brick.
So... say the bridge has a mass of 50 grams, and will hold a weight of 150 pounds, then the ratio would be 3, which is good.
I am currently considering building a pratt, howe, warren, or warren (w/ verticals) bridge. I do not knwo which one will be best for this project. Please help and give any tips. Thanks and happy holidays!
also, i do not know for the trusses, what angles i should use (for the triangles).
specifications:
>30cm long
6cm-6.5cm wide
Please help and give any tips. Thanks and happy holidays!
Any of those types can be made to work.
Your most likely failure modes are going to be joint failure and Euler buckling. You will want your joints to be so strong that the truss members break before the joints break.
Euler buckling is going to be where the strength to weight tradeoff takes place. If your truss members are slender, they will need flanges creating that "I" shaped cross section. This will add weight, however. You will have to decide if the added weight is worth the additional strength.
If a truss member breaks before the other modes of failure, then you have utilized the maximum capacity of your structure. If buckling or joint failure occurs, then you have not utilized the full strength of your truss members.