Bridge Building Techniques

[djroggen]

Trying to get some ideas. Clearly the best way to cross a river is through., but for a practice loop, and with depth ranging from 8" deep to 2.5' deep and rushing. It's not practical to cross multiple times. My river area is about 50' across. Curious what you have done/seen done. Thanks to all in advance for your ideas.

 

[gasgasman]

We use these on our National Forest trails.
http://www.ettechtonics.com/

50' span will run about $100,000.

 

[Fred1956]

I don't know what you have access to in your area, but we have considered spanning some of our steeper ravines with bridges. One of the things we have discussed using is an old mobile home frame as a base platform then decking it as needed. Just a thought at this time as we haven't actually done it yet. Even old mobile homes were 60' long so a pretty good span could be reached.

 

[iamovru]

Trying to get some ideas. Clearly the best way to cross a river is through., but for a practice loop, and with depth ranging from 8" deep to 2.5' deep and rushing. It's not practical to cross multiple times. My river area is about 50' across. Curious what you have done/seen done. Thanks to all in advance for your ideas.

This bridge is a work of art. Scroll down to the bottom

http://ktmtalk.com/showthread.php?t=501793&page=3

 

[swazi_matt]

a few pine trees next to each other - may be a bit bouncy at 50' but good for your balance

 

[mcnut]

I've built two bridges across the creek that divides our property. One is made from metal trusses from a factory demolition. The other is an old mobile home frame topped with expanded metal.
I'll post a couple pictures later.

 

[twowheels]

I just helped a guy build a 50 foot bridge across the river that runs through his property.

Cement pylons, two big iron I beams, and 2" rough cut lumber (16' long, most anout 10" wide).

I'll post a pic later.

 

[bukwheat]

Couple of good size jumps oughta do it....

 

[mcnut]

I just helped a guy build a 50 foot bridge across the river that runs through his property.

Cement pylons, two .... QUOTE]

It's concrete! Cement is only an ingredient in CONCRETE!
Sorry. It's a pet peeve of mine.

 

[Boom Boom]

Thread two larger cables thru skids and tie off cable to a tree or large anchor in the ground. Only one bike at a time and keep the travel speed smooth and even or expect to get bounced off it. This was used for years at one of our trials events...first time across was a little interesting. Many places offer skids for free and you can find used crane cable for reasonable cost.

 

[mcnut]

Both bridges are about 50' spans and are set on stacks of RR ties at each end, anchored with steel posts driven into the ground. The pictures were taken during an "100-year flood" event.

 

[racemx904]

mobile home frame from a old single wide.... then pallets on top..... then cover with chain link fence.....

 

[djroggen]

Couple of good size jumps oughta do it....

Yes I thought about that! The main issue is I need to remove it. It floods out of the banks every spring.

 

[bowhunter007]

All that metal wouldn't last long around here. Damn tweekers will steal anything. That said, the single wide mobile home frames make excellent bridges.

 

[djroggen]

All that metal wouldn't last long around here. Damn tweekers will steal anything. That said, the single wide mobile home frames make excellent bridges.

I found a couple single wides for free. Just have to pick them up. One is only 2 miles from the river bottom it will go. Thanks for all the suggestions.

 

[webmaster]

Bailey Bridge - design for pre-fab simple to build bridge designed during World War 2...

http://en.wikipedia.org/wiki/Bailey_bridge

For a walkway - motorcycle bridge - the 'panels' can be small and easy to move around and assemble into a longer span...

jeff

 

[twowheels]

I just helped a guy build a 50 foot bridge across the river that runs through his property.

Cement pylons, two .... QUOTE]

It's concrete! Cement is only an ingredient in CONCRETE!
Sorry. It's a pet peeve of mine.

Jeez Louise - you're awfully up tight for a guy that gets to ride everyday

I knew it had rained hard down there earlier in the year, but wow! No wonder your hill climbs are like they are.

 

[swazi_matt]

this is possibly the cheapest option
https://www.youtube.com/watch?v=rYOC_3H27Yg
the video is to assist with the concept. We have a lot of these in the rural areas for crossing rivers of much greater span.
I would not go with the turnbuckles and poles, but rather work out a way of tensioning the cables and casting them into a large block of concrete either side. (i would also use a more substantial cable than that

this is a paper that goes into a fair amount of detail:
https://mcedc.colorado.edu/sites/de...ridge-Design-for-Rural-Construction_FINAL.pdf

 

[bowhunter007]

this is possibly the cheapest option
https://www.youtube.com/watch?v=rYOC_3H27Yg
the video is to assist with the concept. We have a lot of these in the rural areas for crossing rivers of much greater span.
I would not go with the turnbuckles and poles, but rather work out a way of tensioning the cables and casting them into a large block of concrete either side. (i would also use a more substantial cable than that

this is a paper that goes into a fair amount of detail:
https://mcedc.colorado.edu/sites/de...ridge-Design-for-Rural-Construction_FINAL.pdf

How much do the suspension bridge move around, while crossing? The suspension bridge would be much easier to tote the components into remote areas.

 

[swazi_matt]

I would think for a short one like this, not very much. We often cross one that is about 50m - and it moves up and down a fair bit but not side to side. The biggest issue is the timber decking rotting and being replaced with sticks etc - we generally walk/ride the bikes across. This one i think has 3 or 4 cables running under the new deck (a few years ago it was an extreme dare to just walk across that bridge!!)

here are some FB pics:
https://www.facebook.com/claudia.tr...t=a.10151118994314369.496934.671549368&type=3