Bridge

[addjunkie]

I need to build two bidges over a stream running through my fields. Easy enough, using rsj and sleepers. Or putting twin wall in and covering. But flow changes, so dont want to use pipe. And sleepers get slippy when wet and muddy. Its only for a quad and trailer, or the Mrs walking.

Any suggestions for materials with a durable not too slippy surface for the deck dont want alpacas with broken legs or hips. Any ideas.

 

[anto44]

Precast concrete bridges or cast in place concrete is what the farmers around here use for livestock crossings over small drains and streams

 

[Shox Dr]

Kicker boards and gravel it, cover it in astro turf, or we nailed down Chicken Mesh on slipy duckboards

 

[gaz1]

use grid platform bridges

 

[dan.taylor.1]

Open mesh panels, like they use for overhead walkways, assuming it's just for a quad and pedestrian / light animals.

 

[tom2207]

how wide ,,, what about a pair of trailer ramps , or a platform off a tail lift .

 

[James1979]

how wide ,,, what about a pair of trailer ramps , or a platform off a tail lift .

See an old lorry flat trailer used a few times. Minus axles.

You can get that fibreglass waffle stuff. We used to use it on ships for the walkways. Light and durable. Really grippy. The load per ton is huge but it’s not that cheap. Kind of do it once price.

Edit. That said. How big are alpaca feet? You can get the waffle quite small - about 20mm holes. I wonder if they will walk on it if they can see through? Maybe it’s not such a good idea!

 

[Wildefalcon]

Oak?

 

[gaz1]

Open mesh panels, like they use for overhead walkways, assuming it's just for a quad and pedestrian / light animals.

it was what i was thinking of as the sides dont need a hand rail just a floor

then i read lower and didnt spot the alpacas but theres no handrail
the op can use the 3mm beam method of box section and have it wide enough for a walkway/quad use

 

[fizzy]

We had a bridge made of sleepers - they covered the wood with galv chicken wire. Plenty of grip.

 

[addjunkie]

Alpacas have soft feet pads and two toes so holes wouldnt really work, Id thought of grating type stuff….not sure on chicken wire, but have seen it done in a few places.

I do use trailer ramps now, but a bit of a pain when quad is 1.2 m and trailer is .9, or mower 1.6m wide!

 

[voipio]

Useful to know the flooding risk. Sleepers run the risk of floating off and getting washed away by high water levels and flows. At least precast concrete wouldn't float.

 

[fizzy]

Useful to know the flooding risk. Sleepers run the risk of floating off and getting washed away by high water levels and flows. At least precast concrete wouldn't float.

Not in Wales - ours were totally waterlogged

 

[gaz1]

any bridge with a cover over is lethal more so with snow on it

wood being the worst as you also have to clean it often as the algae grows on it snow on trailer backs are just as deadly

see throughs are not liked due to the height but are great for not collecting stuff on them oil rigs use them

 

[voipio]

Not in Wales - ours were totally waterlogged

Even in Wales! Once the water level gets to the top of the sleepers, they're near enough buoyant to drift off under the force from the water. Happened to a farmer I know in Wales. Replaced with precast concrete. So far, so good.

 

[James1979]

Even in Wales! Once the water level gets to the top of the sleepers, they're near enough buoyant to drift off under the force from the water. Happened to a farmer I know in Wales. Replaced with precast concrete. So far, so good.

Had stacks of them on the slip ready to pull a boat out. Went for a brew because she was late. High tide came. We went back out and no sleepers!

All floating across Scapa flow.

I wondered about their feet on chicken wire.

What sort of span is it? Could you paint it and put blasting sand in the wet paint? Or use wingwalk buts that’s spendy

 

[DAPPH]

I'd go for galv EXPM nickel steel sheets welded or bolted to sturdy box steel runners , plenty of grip ,water can pass it there are debris that hold onthe bridges they won't float too far away if i-unseated so recovery & resisting could be good
For the buttresses / stanchions dig out & lay in polyprop woven sand bags like a solid brick wall with runninfg cross layers for more strength ,angled back frommth water into to tera firmer , filled with lean dry concrete mix as they'll get damp and solidify , are fairly easy to transport and can be made up a few dozen at a time convenient to you .

Where I used to live they often used H section girders for the runners crossing the 35 foot or more wide drains at Mortons Leam Guyhirn Wisbech. Often too, nine foot dial wriggly tin arcs bolted up to make big culvert pipes in vrious sizes ,sometimes with debris strainer posts in the water twenty feet or more up stream

Other things come to mind sand blasted cleaned ex MOD sand tracks covered in epoxy and sand if the span is not too wide , again on lean mix filed sand bags

 

[nickk]

Old lorry chassis?

 

[tom2207]

Ill go back to an earlier question ,,,,, how wide is the stream.

 

[addjunkie]

No flooding risk, varies between a trickle and about a foot of water wide. Span in reality is 4 foot. Needs to be movable as it silts /grows in in summer.

Its crossed my mind to make a concrete mould, from a sheet of osb, two layers of mesh, then 4 inches of concrete, tamped finish

oh and hasnt got to look like scrap heap challenge!