Posted 1/25/2008 17:43 (#293036) Subject: Center pivot irrigation bridges
We are working on a farm where I am installing a center pivot. There are three ditches that are anywhere from 15' to 30' wide from lip to lip. I am considering using used concrete highway bridge beams where each tower will cross a ditch. Another idea was to buy 20' or 30' culverts and cut them into 10' pieces and use these for tower crossings. Nothing at this point has been decided.
Please share ideas that you have tried that worked well. I am wide open to suggestions. Many thanks.
Posted 1/25/2008 18:23 (#293056 - in reply to #293036) Subject: RE: Center pivot irrigation bridges
South East/Central Nebraska
I know that Geneva Welding in Geneva Nebr. has been making pivot bridges for at least 10 years. He ships all over the US to pivot dealers. It looks like the span goes to 40 feet that he makes, just by judging from what I see setting on the lot. He keeps 1 or 2 men constantly busy welding so they must work and be priced fair I assume.
My description of his bridges are as follows. They are appox. 3 ft wide. Two appox. 3-4 inch pipe are laid parallel with a pipe on each end holding to the desired width. Then he builds an arch over the top I think, raising to maybe 24 inches at the peak of the arch on the longest spans. Then he uses the same 3 or 4 inch pipe to weld steps every 12 to 16 inches apart up the span.
I am not sure how they are kept in place from water that would flow over the ditch in a big rain. Maybe nothing as they would have to be quite heavy.
Posted 1/25/2008 20:09 (#293158 - in reply to #293036) Subject: Pictures on this site
I don't know anything about them, but there are some pictures on this site that may give you an idea. I have a couple neighbors that have bridges and get along good with them. I think they had a local welder make them.
Posted 1/25/2008 20:30 (#293181 - in reply to #293036) Subject: RE: Center pivot irrigation bridges
Whiskey, Tango, Foxtrot
Man, those things look nice but expensive for nothing more than getting a pivot across a ditch.
Have any old trucks around? Scrap everything but the frame, weld some pipes across and use that. Have used them to carry mainlines over canals.
Neighbors got a pivot near me that used 20' culverts at each crossing. Looked fine but so much dirt has blown into the canal that if a guy needed to get water down it I think it would take a while with an excavator just to clean them all out.
Posted 1/25/2008 22:36 (#293329 - in reply to #293036) Subject: ballpark cost?
We are needing to do the same thing over a ditch here. Pivot is already on the ground, 4 tower, was gonna install culverts with dirt and rock, but now wonder what a 40 foot bridge like that would cost? My biggest worry with the culverts is is washes out and I don't see it before the pivot crashes in the ditch. That makes the bridges look more attractive. I also like the way they can be set at an angle. Thanks.
Posted 1/26/2008 16:26 (#293772 - in reply to #293726) Subject: RE: ballpark cost?
I am in SE Nebraska so the freight would not make it practical. That is a pretty good price, the ones from Geneva Welding are much higher and you probably couldn't tell a lot of difference between those and the ones I build. I have the same nice arch in my bridges as the factory built ones.
Posted 1/26/2008 23:14 (#294072 - in reply to #293772) Subject: RE: ballpark cost?
How long does it take to make one of the bridges. How much lead time would you need if I could work something out? Got a neighbor that is wanting some also. He has a semi, so SE Nebraska might not be too far away. Thanks.
Posted 1/27/2008 08:53 (#294210 - in reply to #294072) Subject: RE: ballpark cost?
It depends on the length. I went back and looked at your message and found out you wanted a 40 footer, and I was thinking 30 footer. I think I could make a 40 footer for the high end of the price I said, but I would not want to say for sure until I get metal prices.
I have almost no material on hand, I will have to get some. I need to make at least 2 for myself as well. How many, and what length would you need?
I think a 40 footer could take 2 1/2 days to make. The pipe for the siderails comes in I believe 33 foot lengths, so they have to be spliced to get the additional length, the trusses have to be spliced, it is a lot more work than a bridge 33 feet or less. There is also a LOT of welding on these things, if you do it right.
Give me an idea when you would need them, how many, etc and maybe I can get some metal lined up.
You could also give me a call if you wish. 402 300 0072.
Posted 1/26/2008 12:29 (#293670 - in reply to #293036) Subject: RE: Center pivot irrigation bridges
There's a place not far from you where they used the concrete bridge beams to cross a ditch. Moreau Rice road right inside Lauderdale county off Hwy 87. The only thing I didn't like is how they wound up sort of "out of kilter" after a very short time. Maybe the installation should have been a little different. Looks like a good way to put a pivot into the ditch to me. Just my 2 cents.
Posted 1/26/2008 12:49 (#293679 - in reply to #293670) Subject: Re: Center pivot irrigation bridges
If you are going to use the concrete bridge beams, you need to do a footing on each bank to set them on, or you going to see what BHTN describes in his post.
Now, what has been done "here" and what we are going to do on the ones we are putting in, is talk to the outfit you are getting the pivot from about their scrap pipe. The ones we have use pivot pipe with angle iron welded across them. I have several that we are going to need to do for the 3 pivots that we are putting in, and they are giving us the pipe, we'll have to buy the angle iron and do the construction of the bridges.
Posted 1/26/2008 13:41 (#293704 - in reply to #293036) Subject: RE: Center pivot irrigation bridges
I would look around and see if I could find some decent OLD truck trailers that either could be cut down or a FLAT bed truck or sides removed etc.
JUST saw a article in the paper that said counties are using ALOT of railroad flat cars for vehicle bridges,,,for that cost effective,,,I guess.
I would think 'anything' you use to have concrete footers and approaches on each side for 'permanent' placement. Most of the strength of a pivot bridge has to do with the arch incorporated into it.
Another is sometimes you canfind some 'junk' joists from a ceiling structure (like a walmart store has) and put some cross members to it. longer spans need deeper trusses.
The culvert idea ONLY works IF big rains and flood currents DONT occur there and wash them out. AND sometimes that still occurs. Had one wash out umpteen times,then installed a BIG one that could handle that flow and it is still there,,but washed out sides a couple times!! Their a PIA real quick!! IF you dont have time or no access to check every time it dumps rain,,,go do it RIGHT!! You can see from quite a distance if a bridge isnt there(took down by floating tree and debris??) One upside down OOPS pays the rent!!