I need advice on building a small bridge

[StrangeRanger]

Hi all,

I've got an L3400 HST that I usually have the LA463 FEL and box blade on. I'm estimating that w/ the extra weight I pile on the box blade it probably weighs about 4,000 lbs.

I need to build a little bridge, maybe about a 4-5 ft span over a small culvert to get to my back field. Any suggestions on what you'd use for timber? Or how you'd go about it?

Thanks,
j

 

[jimjdb]

Three ways;
1. Look for a piece of round galvanized culvert pipe and cover with soil and stone or run 4x4's over it with planking to create a "faux" bridge. The culvert is super strong.
2. Use 3 or 4 8x8 timbers with 2" planking over

3. Look for a used steel yard and pick up a couple web beams- they can size them for the weight you want to carry-then bolt wood planks to the tops and 2" cross pieces.

I like the culvert idea best because you can use stone around the sides and create a nice looking little bridge given the short span. The timbers tend to look better with a longer span-look too big and clunky short.
Good Luck!

 

[Tarheeler]

I woulld agree with the pipe as the most feasible, sturdy and eye pleasing:thumbsup:

 

[Tractor Factor]

Another vote for a length of galvanized steel culvert, covered with crushed stone. No worries about whether it's strong enough. Around here it's the standard method of connecting driveways to roads, and really the only thing that farmers use in their fields. If this were a BX tractor I think you could devise a wood bridge to handle the load over that span, but you've got a big tractor there.

 

[jesseb3@att.net]

A buddy of mine poured concrete over the stone, but that was to support large combines out in the midwest.

Whatever you do, photos please! I have a concrete bridge that I may have to replace someday due to erosion.

Does anyone have any data regarding the strength of a simple culvert pipe/stone bridge?

Jesse

 

[tommu56]

look at these links on laminated timber bridges

www.woodcenter.org/docs/lee96b.pdf


Standard plans for timber bridge superstructures

tom

 

[megaboz]

I would go with the pipe as well, just make sure it is longer than you really need, that way any material that way the stone won't fall off into the ditch.

I don't liek the idea of bridges unless you take the time to build it right. When I was younger we actualy just built a plank bridge. It hung over the sides of the creek about a foot on both side. With the constant bouncing and us always going one direction, it eventually fell off the one side of the bank.

If you really want to build it out of wood, I would think 3 6x6 (depending on how wide it is going to be, I like to over engineer) would be sufficent with 2x6 or 2x8 cover boards. Just be sure to anchor it at both ends. I would actually consider digging footers at each end of the support and anchor with lag bolts. That way it won't slide.

If you think there is going to be future issues with erosion, I would consider building a retaining wall on both sides of the culvert under the bridge, depending on how high and wide it is so that the bank doesn't slip out from under it.

Of course my thought might be over kill, but thatis only because I am tired of being hurt by shortcuts that I and others have done over the years.

 

[mustangsallysdad]

Hi all,

I've got an L3400 HST that I usually have the LA463 FEL and box blade on. I'm estimating that w/ the extra weight I pile on the box blade it probably weighs about 4,000 lbs.

I need to build a little bridge, maybe about a 4-5 ft span over a small culvert to get to my back field. Any suggestions on what you'd use for timber? Or how you'd go about it?

Thanks,
j

Galvanized culvert pipe (corrogated, self cleaning type), geotextile cloth and crushed stone will out live you and your children.

 

[jimjdb]

My driveway crosses a stream and has a 3 or 4 ft piece of steel culvert for the crossing. 15 years old and have driven many tri-axle dumps over it loaded with 20 tons of stone. As solid as a supreme court decision

 

[scootr2d]

A friend of mine found an old 16 foot steel frame trailer on Craigslist , axles / wheels etc..were shot . He laid down new pressure treated planking in the bed . Poured two small concrete abutments one on each side of the stream and laid trailer across. He uses it as a bridge across a small stream connecting two pastures. Actually looks aesthetically pleasing and quite strong .

 

[crazyal]

Not sure if there are any around you but around here you can pick up used rail road ties for pretty cheap. People use them for landscaping all the time but often times they are very solid. I would just buy enough to lay side by side giving an extra foot or two on each side with maybe a pressure treated 2x4s screwed across the bottom holding them together. They easily would hold the weight of your tractor and last a long time.

 

[HappyOne]

What's the typical per foot cost for a section of 2, 3 or 4' corrugated pipe?

 

[Ken45101]

What's the typical per foot cost for a section of 2, 3 or 4' corrugated pipe?

It's expensive in those sizes.

If you go railroad ties, I'd buy new ones, not used ones.

Ken

 

[mustangsallysdad]

What's the typical per foot cost for a section of 2, 3 or 4' corrugated pipe?

A good average for the 3 sizes you mention would be around $25 per foot.

 

[ChuckinNH]

This was my somewhat simplified solution. It cost about $160.

 

[HappyOne]

A good average for the 3 sizes you mention would be around $25 per foot.

That's not too bad. Thanks!

 

[StrangeRanger]

I considered the galvanized pipe solution to begin with, but the trouble is that the field I'm driving into is at a different elevation. It's about 3-4 ft higher than where the tractor is stored. I wasn't sure it would be a good solution building up an incline like that. But it sure would be the easier solution.

 

[Flatheadyoungin]

they're harder to find but if you can get some bridge ties...they are 14 or 16' long......

Not sure if there are any around you but around here you can pick up used rail road ties for pretty cheap. People use them for landscaping all the time but often times they are very solid. I would just buy enough to lay side by side giving an extra foot or two on each side with maybe a pressure treated 2x4s screwed across the bottom holding them together. They easily would hold the weight of your tractor and last a long time.

 

[Reg]

Not trying to read too far ahead, but your 4,000 lb tractor as the "design center" could lead to temptations.

It is about the weight of a heavy car or mini truck.
The day might come when a trailer needs to be put back there, so you might want to make it 8ft wide.
An 8,000 lb pick-up might need to go back there too.
I guess I'm just saying plan for more than your immediate wants/needs.

I would go with the smallest diameter galvanized culvert that can handle the flow (+ some 50 year worst case Spring run-off flood, or whatever comes that way) too.

 

[mustangsallysdad]

Not trying to read too far ahead, but your 4,000 lb tractor as the "design center" could lead to temptations.

It is about the weight of a heavy car or mini truck.
The day might come when a trailer needs to be put back there, so you might want to make it 8ft wide.
An 8,000 lb pick-up might need to go back there too.
I guess I'm just saying plan for more than your immediate wants/needs.

I would go with the smallest diameter galvanized culvert that can handle the flow (+ some 50 year worst case Spring run-off flood, or whatever comes that way) too.

If I'm not mistaken, there should be a proof mark on the pipe that indicates the load compression rating...in any case, my county uses 24" at the ditch junctions on the paved single lane roads and they do see loaded plow/salt trucks and logging vehicles...hope that helps.