How to build a bridge over a small creek

[MossRoad]

There are quite a few threads on bridge building here on TBN in the projects forum and other forums. Just do a quick search on TBN for build AND bridge and start reading.

 

[BillCroasmun]

ontheweb,
Great links, thanks! I have a small ditch/creek I have wanted to build a decorative arched bridge over but figured it wouldn't be sturdy enough for the PT. I have been contemplating making two: one decorative foot bridge and one sturdier tractor bridge in a less visible area. After reading that site a bit I think I can (relatively) inexpensively build one bridge for both purposes. /forums/images/graemlins/laugh.gif

 

[redsox2004]

Hi,

I am looking to also build a wooden bridge across a 20' creek that has different levels on the sides. The bridge needs to be 6' wide, over 20' long (creek bed is 20') and able to handle at least 2,500 tractor.
I was thinking of using 4x6 posts buried in 12"x4' deep concrete sonotubes. There would be 3 sets of 3, center of bed and near the two banks. I was hoping that two 2x12's would make a strong enough beam and space them at 16" on center. I would carraige bolt the two 2x12's that are are either side of the 4x6 posts and lay the 2x12 joists on top of them and screw 2x6 on top for the decking. I know there is more to it then this so I am looking for some advise. It is in Michigen so I have a 42" frost line. Also, this is only an active creek in the spring and fall, it is dry right now. the creek is roughly 1,000 feet from the road so having trucks for concrete or a crane is out of the question, this has to be done by hand. I also need to be careful because the creek is only 14" to 3' deep. I am also concerned that the low side will be under water in a big flood that happens maybe once every 5 years. Oh one other thing, the span for the double 2x12's would not be more then 8' due to the pilliers and 2x12's bolted on the sides of them.
So there you have the info, mindset and challanges, any ideas?

 

[sldva00]

The following link is to a bridge made by a TBNer. Don't know if it will meet your needs, but it was well built.

http://www.tractorbynet.com/forums/build-yourself/171787-another-bridge.html

 

[rekees4300]

I am pretty sure this has not been discussed here. A google search did not provide me with any ideas.

There are several threads at TBN discussing this topic. Instead of Google search, use the TBN Search function, enter "bridge" as a keyword and select "Search Titles Only"

 

[Bob999]

Have you considered using PVC conduit. It is available in 20' lengths and diameters up to 2' or more. Two or more lengths side by side are used where there are large flows.

The conduit is simply laid in the stream bed and covered with soil. So far as I know the life time is unlimited and there is very substantial load carring ability--it is used for drainage under public roads.

 

[pajoube]

Bridge would need to be about 20 ft in length. About 5-6 ft wide. Sorry for not providing these figures earlier. Pt 1430 as I understand it weighs about 3,000#, plus implement...add another 200 or so.

As far as available construction material I am open to suggestions as the material would need to be purchased.

Get a flat bed trailer that has been damaged (undercarriage), this will give you the length, width, and strength you need. Just set on cement pilings on both ends.
PJ

 

[KeithT]

find an old mobile home. The steel beams are very stout.

 

[MossRoad]

Hi,

I am looking to also build a wooden bridge across a 20' creek that has different levels on the sides. The bridge needs to be 6' wide, over 20' long (creek bed is 20') and able to handle at least 2,500 tractor.
I was thinking of using 4x6 posts buried in 12"x4' deep concrete sonotubes. There would be 3 sets of 3, center of bed and near the two banks. I was hoping that two 2x12's would make a strong enough beam and space them at 16" on center. I would carraige bolt the two 2x12's that are are either side of the 4x6 posts and lay the 2x12 joists on top of them and screw 2x6 on top for the decking. I know there is more to it then this so I am looking for some advise. It is in Michigen so I have a 42" frost line. Also, this is only an active creek in the spring and fall, it is dry right now. the creek is roughly 1,000 feet from the road so having trucks for concrete or a crane is out of the question, this has to be done by hand. I also need to be careful because the creek is only 14" to 3' deep. I am also concerned that the low side will be under water in a big flood that happens maybe once every 5 years. Oh one other thing, the span for the double 2x12's would not be more then 8' due to the pilliers and 2x12's bolted on the sides of them.
So there you have the info, mindset and challanges, any ideas?

I would not encase wood into cement. If something happens to the wood, the whole pier is ruined forever and eternity. Instead, build the cement pier to the proper height in the first place to lay the bridge on top of it OR put anchor bolts into the top of the pier and use steel plates to bolt the wooden legs to the cement pier.

Also, consider strongly the option Pajoube offered regarding finding an old flatbed trailer to use. That way, all you will have to do is put in concrete piers on either side of the creek at the proper locations and set the flatbed on top of the piers. DONE! Simple as that. :thumbsup:

 

[SpringHollow]

Encasing wood in cement speeds up the decay.

Ken