Advice on building trail structures?

[dubprof]

Originally Posted by ryando

I'm considering a dirt-top bridge to replace a rotten cedar bridge over a creek and have a few questions.

The two different build methods I have seen are: slats and doubled-up stringers to hold in the dirt, and stringers and landscape fabric with no slats. Anyone know which method is better/lasts longer? When you build without slats, do you double up the outer stringers or just use larger diameter outer stringers to crib in the dirt? One last question, how far apart do you space the stringers that are under the dirt?

NOW this is a much better example of an approriate building question for the internet - its specific and to the point - looks for input on one specific idea and can be discussed appropriately...pictures can be provided to back up discussion as well as expereinces assosciated with building this type of structure.

myself - never built a dirt topped bridge so I will defer to those who have. My only opinion is that i would never do it. don't like the look - dont want to carry in the materials and it dont really make sense to me to build a water resevoir on top of wood that keeps the water in place longer than having it drain off...but its the new trend nowadays. If ya want yer trail to be hip go for it....and yea i know i could be wrong on this one...but im sure that there arent many evidence based studies out there comparing the length of life of a slat topped bridge vs. dirt topped...

I've already been told im out of touch cuz i built a couple skinnies on my trail. dont ride it then is all i say.

[biggles604]

A properly built dirt topped bridge won't hold water, it will let it pass through. as for the look; there are probably a couple of really well ridden examples that you didn't even know were bridges, such as the one on Pangor.

[dubprof]

Originally Posted by biggles604

A properly built dirt topped bridge won't hold water, it will let it pass through. as for the look; there are probably a couple of really well ridden examples that you didn't even know were bridges, such as the one on Pangor.

and thus - is why i deferred to people who have built them....somehow though i think dirt still doesnt dry as fast as an exposed surface..just ny two cents - which seems to be worth less and less these days...and im fully aware of the work on Pangor... when i hear bridge i think - long, elevated ...ya know...a bridge. not a step.

[Uncle Duke]

Originally Posted by dubprof

...and yea i know i could be wrong on this one...but im sure that there arent many evidence based studies out there comparing the length of life of a slat topped bridge vs. dirt topped...
.

i have 3 dirt toppers that are over 5 yrs old, no pooling ever and so far rock solid. def one of the best ways to go.....

http://s1131.photobucket.com/albums/...dirt%20topper/


this goes back to before the dee-vorce when i was still a fun and happy person...

[Uncle Duke]

greg,issac,julien and silk all in one shot...memories...








most folks have no idea its dirt topped,

thnx again to all the peeps for making it happen!! circa 2006-07..

[shirk]

That build day got lots done. Good times.

[Uncle Duke]

ashek the one and only langdale bomber



and my main man dave , stayin safe at all times is important...

[Uncle Duke]

rockn the nsmb hoodie





who what?









wicked wknd!

[heckler]

[heckler]

Originally Posted by dubprof

when i hear bridge i think - long, elevated ...ya know...a bridge. not a step.

the "step" has a 2 foot wide creek under it that used to be a water spring that popped up on the trail and ran down the trail 100 meters or so, destroying it.

ref my previous post of photos.

the "step" is also a landing zone with heavy braking for the drop before it. I'm really surprised how well the dirt has lasted on it, and I'm sure it's because of chris and biggles effort to strain out the rocks first.

[Wernie]

built dirt tops going back to '97 or so; my not so humble opinion:
- you don't need lanscaping cloth - never used it, never will
- you don't need to sieve, like Duke said, just rake out the big rocks
- if you can keep riders off it for a few weeks of rain, it will set up rock hard with minimal packing (the wonders of good gold)
- for a wide, high-speed bridge, i would do as Duke's build, with slats
- for narrower bridges, like 1-3' wide, the multiple stringer approach is faster as the most time consuming part of any bridge is if you need to split or mill rungs
- a base of multiple stringers with quality wood also gives you a bridge that could takes motos with ease
- i can build a narrow dirt top bridge with the multiple stringer approach faster than i could build an equivalent conventional non-dirt top bridge with rungs
- crown the bridge and the water will sheet off

if you want to haul landscaping cloth and a sieve into the forest, more power to you, but it is not necessary.

[Jerry-Rig]

Sifting is not necessary but the dirt will hold up longer. Good dj's are sifted.

[Bryce]

dirt-topped is generally nicer to ride too

[Uncle Duke]

Doesnt get slippery in the wet, or snowy conditions..another digger creation as far as i know... Def sweet..

[shirk]

pfft all this talk of dirt topped. Just go concrete like the one at the end of Grannies.