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Building a Single Lane Covered Bridge

BHackford_'s picture

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I need to build a residential bridge that can cross a small creek, however, the dry creek bed of the small creek is about 45 feet long so the bridge must span about 50 feet. The preferred design is a covered wooden bridge. Any information (i.e. required permits, deck design, overall design, location of reference materials, etc) you can provide to help me build this is much appreciated.

(post #163609, reply #1 of 18)

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BH, I'd suggest a railroad flatcar as the structural element of the bridge. They can be had in lengths to 90'. Attach sides and roof to make a covered bridge. Should last darn near forever with minimal maintenance.

(post #163609, reply #2 of 18)

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As to permits, it ALL DEPENDS. You might not need any or you may need not only structural and building permits, but also enviormental and stream impact permits (and possbily others).

(post #163609, reply #3 of 18)

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Try this site. Lots of covered bridges for inspiration.
www.tfguild.org

(post #163609, reply #4 of 18)

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Where would I get a railroad flatcar? And any ideas on a fair price?

If I did not go the flatcar route, how many piers would I need and what span? What size timbers for the floor supports (joists)? Is there a code book specific to wooden bridges?

(post #163609, reply #5 of 18)

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Bill is absolutely correct, be careful or very sneaky.
The rule of thumb in WA state is that if you can't get by without permits, don't even try if any kind of stream is involved. Tried to build a 10 ft dam 20 years ago across a seasonal creek, ABSOLUTELY NO WAY according to game department, who got a vote. You'd need an environmental impact statement here now also. A deteriorating main thoroughfare bridge near me cannot be replaced because of possible alleged salmon per impact due to out of stream foundation work (heck, never mind the March earthquake sent 1000s of yard of hillside into the same small river 100 yds downstream)

(post #163609, reply #6 of 18)

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Don't know where you live, so I can't be too specific. Call the railroad nearest you, Car Department Manager (if listed), if not, the Superintendent's office (or the equivalent), ask the clerk who will probably answer the phone for the Car Department Manager's number. The manager will be able to tell you which contractor in the area scraps out their old and derailed cars. The contractor should have the equipment to move a flatcar to your site and set it on piers. Price varies greatly depending on how far the car will have to be hauled, the terrain, and the contractor's greed. I've seen some cars sold to ranchers adjacent to a derailment for $300, set in place. Expect to pay more.

(post #163609, reply #7 of 18)

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The bridge is being built in PA. Do you know what the weight capacity of the bridge would be? It would only need to hold about 3 tons at the max.

(post #163609, reply #8 of 18)

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Shouldn't have any problem finding a scrapper in PA. Flatcar capacity would vary with the design but should be good for 30-40 tons, minimum. Spent 5 months in Greenville in '74 at the Greenville Steel Car Company. I'm not really sure what RR's are left after the consolidations and mergers but I wouldn't think you would have a problem finding a car. Look in the yellow pages for railroad equipment and the business pages for a nearby railroad.

(post #163609, reply #9 of 18)

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BHackford,

Unless you happen to run into that guy with a pick-up load of Craftsman tools, you may find it cheaper to buy a bridge than to stick build it. See this site . . .

http://www.sweets.com/index/search2.htm?i=s&q=02852+-+bridges--pedestria...

The railcar idea is a good idea if transportation is possible. (ie; wide load permits, overweight permits, escort requirements, crane set-up and staging area requirements etc.)

Another source is scrapped bridge beams (precast or steel) Sometimes fabricators make an OOPS and the stuff just sits around the yard or goes to a scrapper. When our DOT takes a bridge down the precast beams are still in pretty good shape. Not sure where they scrap them though. A heavy/highway contractor in you area would know though.

Good luck,

Eric

(post #163609, reply #10 of 18)

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I got an estimate on the "flat bed idea" and it is $10K which I think is very high, but I am still shopping. I am going to re-measure and take another look at the creek to see if the span can be shortened. If I stick with the first thought of a wooden bridge, does any know what type of sub-structure would be needed to carry 3 tons plus the roof? What could the longest span between piers?

(post #163609, reply #11 of 18)

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In 1989 Congress funded the National Timber Bridge Initiative. In 1995 that was changed to the Wood in Transportation Program (WIT). This was adminstered by the USDA Forest Service. U of Maine in Orono was active and Mount Wachusett Community College in Massachusetts put up some bridges in state parks. There was some county in Ohio that did a lot or "re-decking" using laminates. Call your local congressman and have one of his helpful staff or interns get you the name of a local contact or at least find out if there are some approved plans. If you are lucky you may qualify for some grant money.

(post #163609, reply #12 of 18)

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You may want to reconsider that 3 ton loading. I'm assuming there is a house on the other side of the creek. Do you plan on using a moving van to move into your house. How about fire truck access or a fuel oil truck. You may want to consider a 10 ton loading. Timber bridge is probably the cheapest way to go. Laminated Concepts out of Big Flats, NY may be a place to start. 607-562-8110

(post #163609, reply #13 of 18)

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I am really not concerned with moving trucks because the bridge is only for a cottage and I would be moving myself but fire trucks are a concern. I was hoping I could make it very cheap with the use of old cover bridge technology. With two enhancements realistically carry 3 tons and last for 20 years of seasonal service. So if anyone has any plans for a bridge that fits this criteria please let me know. However, it looks like I am going to have to buy some form of a bridge or hirer an engineer for the design.

(post #163609, reply #14 of 18)

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In these lawsuit happy days I guess I'd be more concerned about any liability you would have if it collapsed with someone else driving over it. Would it have to be inspected by the highway department at fixed intervals or is this a private drive that you could limit access to?

Beats me, but I'd probably be asking.

(post #163609, reply #15 of 18)

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This is for a private driveway and the access would be limited by a steel gate at the road. So, does it still need to be inspected? Do I need permits?

(post #163609, reply #16 of 18)

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In New York, for a private bridge you would need a permit from the building inspector and a possibly a permit from the dept. of Environmental Conservation. The building inspector would probably require stamped plans from an engineer depending on your town. I would highly recommend it, especially for your foundations. It just takes one "100 year" design storm to scour out your foundation. And that storm could come next week!

(post #163609, reply #17 of 18)

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I need to build a residential bridge that can cross a small creek, however, the dry creek bed of the small creek is about 45 feet long so the bridge must span about 50 feet. The preferred design is a covered wooden bridge. Any information (i.e. required permits, deck design, overall design, location of reference materials, etc) you can provide to help me build this is much appreciated.

Single lane covered bridge - what did you do? (post #163609, reply #18 of 18)

After all the comments, what did you end up doing?  I need to build a similar bridge in Branson, MO and any advice would be appreciated.