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RichInTheUSA
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# Posted: 7 Jul 2014 09:12
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I have a road that goes over my creek... right now there are 3 culverts in the creek, with lots of concrete pored over it (not my doing). This bridge has been in existence since the 70's.
I'd like to have several loads of gravel delivered, and the weight of the truck + gravel is just under 30 tons.
I'm in the process of checking liability insurance with the quarry who contracts drivers to deliver.
My other option is to buy a bridge. Anyone know how to go about finding small bridges to buy? Any thoughts on load?
Anyone been down this path before, and can give good advice?
Thanks, Rich
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OwenChristensen
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# Posted: 7 Jul 2014 18:54
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Sounds like your culverts are strong enough to me. We had a 20' bridge made from steel I-beams and a wood deck. It was very strong. Many loads of gravel and concrete trucks went over it. It lasted for about twenty years, then washed out. The new owners asked the DNR if they could replace it. They said , no, you need to use culverts. What a shame, the bridge had a lot of charm.
Owen
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Don_P
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# Posted: 7 Jul 2014 19:01
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The load capacity of a culvert works around the diameter and the amount of cover. A larger diameter pipe with little cover is weak where the same culvert with a healthy cover is quite strong, the force flows through the arch in the soil rather than bearing directly on the pipe. You can also timber plank over the culvert to help distribute a load.
Culverts beat bridges any day if possible. Old flatbed trailers or flatbed railcars can be used as bridges. We also have several dealers in salvaged I beams in the region.
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bldginsp
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# Posted: 7 Jul 2014 22:16
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I knew a guy who needed a bridge, considered getting a flatbed rail car, but after looking at cost concluded that a bridge made by him out of Doug fir trees on the property was far less in cost even after he factored in replacing the wood every 8-10 years. Costs might be different in different areas. A truck or rail flatbed isn't permanent- they will succumb to the elements too- just takes a little longer.
Wouldn't be surprised to find that the reason they covered covered bridges was to save the bridge, not for the comfort of travelers. But that's speculation.
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Don_P
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# Posted: 7 Jul 2014 22:34
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That's the reason for covering a wooden bridge, as long as the roof is kept intact they are very long lived. Those bridges were actually drive through trusses, the wall framing usually contained kingpost, queenpost, bowstring, pratt, howe or lattice type trusses, many of these truss types are names you will recognize still, in common roof truss types... although the members were a good bit beefier. With the advent of large steel and the machinery to set it we reverted back to simple span beam bridges, the type we commonly see today. In the neighborhood is one remaining camelback truss bridge made of lightweight steel, the type they could erect around the turn of the century, angle iron, rods and rivets in a pratt truss configuration. Still in use as a one lane bridge, it used to be a train bridge back when they hauled iron ore to a nearby furnace. At a century old and poorly maintained it has outlasted the next bridge over the same creek by 70 years, a modern concrete decked steel beam bridge, they redid the deck on that one just a couple of years ago.
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RichInTheUSA
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# Posted: 8 Jul 2014 05:33
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Owen, The concrete over the current culverts has cracked and the earth underneath the concrete has washed out after flooding this past winter... we now have a hollow space under the bridge. (I should have mentioned this in the first posting.)
This has happened before, and my neighbor mixed up 10 bags of sakrete and pored it into the holes/cracks. Perhaps we just repair this bridge again in the same manner.
Don, thanks for the advice on culverts over bridges.
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OwenChristensen
Member
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# Posted: 8 Jul 2014 08:25
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This is interesting, please keep us posted.
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old243
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# Posted: 8 Jul 2014 14:25
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possibly you could get the gravel delivered in a smaller single axle truck. that would weigh less rather than the tandem. Or have them deliver a load to your culvert, repair the washout and add additional cover, over the culverts, then haul the other loads later. old243
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