I walked some gorgeous trails yesterday around the perimeter of an otherwise fairly non-descript plantation forest near me. Presumably 'created' by dog walkers as there is little evidence of bike use and they probably wouldn't appeal to most anyway (too janky and stop-starty for e-bikes I imagine, too flat and pedally for Enduro, basically only enjoyable on something light and tight like XC or CX bikes I would think).
Anyway, there's a good number of deep, muddy drainage ditches to cross and even if they were rollable they look like a broken collarbone waiting to happen if you get it wrong. I'd love to bridge them in proper old school style, single plank skinny bridges, maybe even some chicken wire if I'm feeling lush. The alternative would be to fill in the bottom with old logs to make them less abrupt but I imagine that would just end up blocking the ditch..
Just wondering what thickness plank will withstand 100kg of cyclist and bike, 1" thick? I'd love to buy some cedar planks for the task but not sure if there's a more cost effective source that is still relatively weatherproof...
Is the solution not to learn to bunny-hop them rather than making gorilla modifications to the trail which potentially increase user conflicts? Â
We did this in our local woods, just used a scaffold plank, the dogwalkers loved it. Unfortunately the motocrossers didn't, they trashed it and threw it in the ditch with some branchesÂ
Is the solution not to learn to bunny-hop them rather than making gorilla modifications to the trail which potentially increase user conflicts? Â
No, it's a sort of inverse bell curve shape, you'd need to bunny hop a distance of about 1.5m from a downhill entrance onto an uphill landing, and typically coming in with virtually no speed. Even a good old school sort of pedal wheely would have you thumping down onto the upslope, assuming your rear wheel didn't slip and you just sort of t-bone the upslope with your front wheel 😬
Given the existing attempts at bridging the ditches I very much suspect a wee chickenwire plank bridge would be welcomed by other users (two or three ditches already have planks of varying degrees of shadiness).
Scaffold boards at 38mm thick are definitely strong enough and a decent 'not too skinny' width. Â Cheap used on eBay or if you have access to a site....
Scaff plank and bang U-nails in for grip - they don't wear out the same way chicken wire does.
I wouldn't use scaffolding boards. I used some to make some raised beds and even though I treated them with preservative they lasted 2 years before rotting and falling apart.
Pressure treated timber I reckon, over an inch thick should be OK, depending on the span? Maybe a double thickness if in doubt?
OK so the answer to your structural engineering question depends on the span that is being covered, the type of wood, the dimensions of the wood, what the fattest person who will actually use it (and assume they bounce up and down in the middle!) - surely 150kg+ more likely, what safety factor you want to build in for it gradually getting weaker with age etc. Chicken wire is a maintenance mess. Of course its possible those ditches have been "designed" that way to discourage e-bikes etc. so personally I'd want a discussion with the land owner/manager.Â
Scaffold boards looks like a good shout, half the price of cedar planks!
Surprised they rotted though, looking at one supplier website it suggests they're designed for outdoor use? Perhaps different if physically laid on wet muddy ground...
I like the U-nails idea also, would probably look better than chicken wire, kinder on dogs feet too I imagine...
Surprised they rotted though, looking at one supplier website it suggests they're designed for outdoor use? Perhaps different if physically laid on wet muddy ground...
Soil contact os a massive accelerator of rot.
While scaff planks are designed for outdoor use, this would be limited to a few months with safety inspections every week and dodgy ones inspected and replaced after each use.Â
Would still seem like the obvious solution for your application mind, you'll just have to go and turn them over to check the condition of them occasionally. Can see why the actual landowner might be reluctant however.Â
Corrugated plastic pipe of appropriate diameter, ensure a decent slope to drain any water away, and backfill with stones and soil
Corrugated plastic pipe of appropriate diameter, ensure a decent slope to drain any water away, and backfill with stones and soil
This. Anything else is just a temporary bodge.
if you are looking at spanning the full 1.5m I'd honestly go for a 2inch/50mm timber (so a 200x50 or 150x50 laid on its side). there's a bridge like you describe in the woods near me that must be only about a metre long and a 1 inch board is a bit springy in the middle.
as mentioned above contact with the ground is the killer, if you arennt planning on spanning the full 1.5m and rather will be having it within the U shape of the gulley, is there some way you could have it sat on a single house brick at each end so even if it isnt fully out of the dirt the bit thats taking the load is?
Anything built using wood on a trail should be thought of as a temporary thing which will require maintenance, even if you know what you're doing eventually it'll need some tlc.
Are you prepared to fix it when it breaks?
Are you prepared to deal with the backlash from walkers that are going to have an issue with you installing something that's probably going to stand out like a sore thumb?
It won't be quick to build, so you'll probably have to be ready for a lot of conversations with said walkers if this is indeed a fairly popular walking spot!
Can you build it in a way that's strong enough for it to be safe? If someone falls off on it then it could be a pain for both of you.
Is it honestly going to be that much fun to ride?
You'd possibly be better off finding a slightly different route to ride to avoid the wet parts, anywhere that's above the lowest part of the trail should be drier than these bogs.
Sorry to be a naysayer, but I'm a (still fairly inexperienced, but keen) trail building noob and all of the above things shouldn't be taken lightly really.
@Stevelol - all fair points!
The idea of wooden bridges was sort of to replicate what bridges already exist, there is a 'precedent' of sorts in this woodland for single plank bridges across the ditches (say out of 12 ditch crossings that exist, 2 already have single planks across them and 1 used to). The ditches are long, linear features so there's no way around them really. Â
That also sort of addresses your point about safety etc. i.e. even if they weren't safe, similar already exists on the trails. Whether that means the landowner doesn't suddenly find himself liable for someone slipping off one of the existing plank bridges and twisting an ankle I don't know, but it's not exactly a sanitized trail environment as it is...
If it wasn't quick to build I wouldn't be doing it, I have limited enough spare time as it is, I could probably afford to dedicate a day, two max to this one. The suggestions above about drain pipes, rocks, soil etc. are all totally legitimate and probably the 'correct' answer, but would change the nature of the exercise.
Having said all that, perhaps the compromise solution is to put down the corrugated drain pipe and lay old logs over the top. This will be fairly unobtrusive to look at (you might not even see the corrugated pipe) and most of the building materials are already there, lying around (i.e. old logs). It wouldn't require any structural strength either as nothing is elevated or spanning any sort of gap...
Is it honestly going to be that much fun to ride?
Well that's entirely subjective, put it like this, when I lived in Vancouver I spent all my time looking for the wooden features on the trails, not the flowy jumpy features 😎 Either way, it's more fun than jumping on and off the bike for the steep sided wide ditches, although I did originally just consider this as extra training for CX...
Only problem with wood already there is that it'll rot quickly.
If you aren't seen/spotted then perhaps you'll be fine. Going in and adding new bridges and by the sounds of things start riding bikes that aren't being done now, there is every chance the bridges will be removed.
It is difficult as it sounds like there is a real need for fixing them, but also sounds like it might not be welcomed to have bikes then using the trails...
If you are spotted/seen then likely you'll have a conversation or 2 about it not being suitable or allowed.
Good luck!
I'd go with the corrugated pipe and backfill, keep your eye out in around roadworks and building sites, they often end up with shorter sections that no doubt end up in the skip...
Going in and adding new bridges and by the sounds of things start riding bikes that aren't being done now, there is every chance the bridges will be removed.
+1
The arrival of tyre ruts and new bridges at the same time will likely be noticed....
Going in and adding new bridges and by the sounds of things start riding bikes that aren't being done now, there is every chance the bridges will be removed.
+1
The arrival of tyre ruts and new bridges at the same time will likely be noticed....
Depends who owns the land. A regular dog walk near me is over land which is owned for the last 50 years at least by a family whose only interest is applying for planning permission for new houses every 5 years. It gets no maintainance and is a mix of scrubby Sycamore and overgrown Rhodies, along with a few old oak and Beech from when it was part of a country house estate until the 1950s.Â
So I have improved the paths slightly by carrying half a bag of gravel at a time in a rucsac when walking the dogs and sticking it on the muddiest bits.
For the OP the pipe and backfill would have the advantage that it would take a bit more effort from other casual users to destroy whereas a plank is easily picked up and thrown away. Â
Might be worth chatting to these guys:
This is more the Tayside Trails patch, wouldn't want to start a rumble! 😉Â
A regular dog walk near me is over land which is owned for the last 50 years at least by a family whose only interest is applying for planning permission for new houses every 5 years. It gets no maintainance and is a mix of scrubby Sycamore and overgrown Rhodies, along with a few old oak and Beech from when it was part of a country house estate until the 1950s.
Yeah, sort of this, I appreciate the warnings about upsetting locals but this is a pretty unloved patch of plantation forest, although clearly enjoys just enough upkeep to keep deadfall off the 'beaten' track. I think so long as I kept any ditch crossings sympathetic to the surroundings (which is why I'm hesitant about digging or putting down gravel...) I should be OK. It won't receive much tyre traffic as it just wouldn't be attractive to the majority of cyclists I imagine (basically hardcore XC or CX perverts only 😎 ).
Point well made about the more effort being required, this is why I like the idea of the corrugated drain pipe underneath whatever 'local' logs I can lay on top, as the existing ditches are all partially filled with old logs anyway and even if they rot they're not suspended in any way so no danger of collapse.Â
I've done the plank thing on lighter used trails.
Measure up then build the wood bits in the garage, either a straight bit ~40mm thick and 120 or 150 wide for a shorter span, or add some depth and a "T" shape for longer spans (or something a bit more substantial!). Then something to make it grippy. Carry it in with a spade, hammer and some hardcore if needed (i can usually get enough locally though) then dig out some foundations 15-20cm deep, 40-50 long. Then fill it with rocks/gravel/half bricks, stamp it down then run the plank and build up round it with more "stuff". Finish off with a couple of iron stakes through the plank to slow down the arseholes who want to move it.
Takes an hour or so on site.
Always got landowners permission though. Hell, one of them even uses the bridges when he's out on his MX or walking the dogs.
Bigger spans we usually chop down a couple of small trees and make a plank bridge, the rest of the process is similar though.
Takes a lot longer, and i sometimes have to carry a chainsaw in...
Could you fabricate something out of a few lengths of 100x100mm or 50x50mm plastic fence post? Something like this but paired/tripled up and bolted together with galvanised coach bolts?
Get yourself a froe and a mallet and you'll be able to split timber that has fallen in the forestry length ways. Couple of trunks across the ditch then the split section on top.Â
Green (ie. unseasoned) Oak railway sleeper. Â Worth the small amount extra as it will last so much longerÂ
Oak is prettyhopeless on contact with the ground.
Some nice big tropical hardwood posts... Or some sweet chestnut.. or accoya.
Go hard or go home.