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Thread: Boardwalk!

  1. #1
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    Boardwalk!

    Over the last 3 weeks, I constructed an 80' long, 3' wide boardwalk right where the trail crosses a seep/drainage. Pressure treated 4x6 was used for the footings and stringers, untreated rough cut 3"x12" spruce [recycled] was used for the decking. Fasteners consist of galvanized rebar, 12" and 6" ardox spiral spikes.


    The material was hauled into the work site on shoulders and by bike, primarily by two buddies and I. The build was a solo project, but took less time than I thought it would. It's a bit overbuilt, but whatever. I did one test ride on it, and then a group of runners appeared and zipped across.


    So far so good - drainage down the slope is unimpeded, the decking has grip when wet, the drop off the high side is less than two feet, and I haven't got hate mail or death threats yet. Best of all, I don't have to ride through 6" of muck to get to the nice trail on the other side.

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    Very nice! People on foot may benefit more than us cyclists, but it's all good!

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    Nice work! I like it when people think of all the trail users when building. Some bikers might want elevation changes and skinnier sections, but other users might not like it as much and complain.

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    Very nice! We are currently doing the same thing at Raccoon mountain on the new addition for crossing over drainages.
    Too wet to ride!

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    cheers, looks great! It's always nice for anyone to get out of the muck and take it easy for a bit.

  6. #6
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    Quote Originally Posted by pinkrobe View Post
    Over the last 3 weeks, I constructed an 80' long, 3' wide boardwalk right where the trail crosses a seep/drainage.

    It's a bit overbuilt, but whatever. I did one test ride on it, and then a group of runners appeared and zipped across.
    Nice work! Recycled means money saved as well, just sweat and love to build.

    Quote Originally Posted by Mr. Lynch View Post
    Nice work! I like it when people think of all the trail users when building. Some bikers might want elevation changes and skinnier sections, but other users might not like it as much and complain.
    If you build on a multi use trail without considering the other users, you are shooting yourself in the foot. The more we do for other users, the more they want us to do. Takes time, but it will happen; think of it as a long term investment.
    "The physician heals, Nature makes well" - real fortune cookie

    CCCMB trail work for trail access - SLO, CA

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    Nice work!
    Here in Greenfield NH, we build most of the bridges 24" wide to accommodate multi-use, we use 4 X 4 oak stringers, with 2" oak decking, and galvanized lags to hook the decking down. The bridges hold up well.
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  8. #8
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    looks sweet, might steal the design for a shorter version
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  9. #9
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    Hey, thanks to all for the kind words! With regard to multi-use, that's exactly what the trail is. We have hikers, bikers, trail runners, horses, cows, deer, bears and moose all using the trails. You know you've done a good job on a trail when you get multiple shoe, hoof and tire prints plus a big dump of bear **** all on the same day!

    I definitely could have made it narrower or with more entertainment value for bikers, but it's really only there to get [all] people past a squishy, calf-deep muddy section that appears every April and doesn't go away until the end of July or sometimes August. It's not fun mud, where a well-timed rear wheel pop splashes your unwary buddy, it's gloopy goo that inevitably flicks off your tires and gets in your mouth and all over your legs. People were actually skipping that section of the trail because of the mud. Hopefully it's a bit more enjoyable now.

    If anyone wants details about how it was built beyond what I've already stated, I'm happy to get additional pics and provide a full description.

  10. #10
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    Quote Originally Posted by pinkrobe View Post
    Hey, thanks to all for the kind words! With regard to multi-use, that's exactly what the trail is. We have hikers, bikers, trail runners, horses, cows, deer, bears and moose all using the trails. You know you've done a good job on a trail when you get multiple shoe, hoof and tire prints plus a big dump of bear **** all on the same day!

    I definitely could have made it narrower or with more entertainment value for bikers, but it's really only there to get [all] people past a squishy, calf-deep muddy section that appears every April and doesn't go away until the end of July or sometimes August. It's not fun mud, where a well-timed rear wheel pop splashes your unwary buddy, it's gloopy goo that inevitably flicks off your tires and gets in your mouth and all over your legs. People were actually skipping that section of the trail because of the mud. Hopefully it's a bit more enjoyable now.

    If anyone wants details about how it was built beyond what I've already stated, I'm happy to get additional pics and provide a full description.

    yes please
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  11. #11
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    What types of consideration are used when posts are set in a drainage area?

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    Gal. rebar to hold posts and footings to the ground?

  13. #13
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    Quote Originally Posted by Fuglio View Post
    What types of consideration are used when posts are set in a drainage area?
    For posts in wet ground, I don't know of many types of wood that won't rot out quickly. Pressure-treated wood is okay, cedar is better. I haven't got experience with hardwoods, maybe they last longer?

  14. #14
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    impressive! Did a 55' footer at the elementary school course we constructed. Literally tons of work. Incorporated multi-users in ours too. All rycycled material except stringers and fasteners. Used Recycled Trex type decking (no horses or motors). Looks like a rugged-ass construction!

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    Quote Originally Posted by pinkrobe View Post
    For posts in wet ground, I don't know of many types of wood that won't rot out quickly. Pressure-treated wood is okay, cedar is better. I haven't got experience with hardwoods, maybe they last longer?
    Cypress Pine logs? Back in the day here it would have been turpentine.

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    Agree.

  17. #17
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    I promised a bit of a step-by-step and more photos:

    Step 1: site assessment
    I knew this stretch of trail pretty well, as our club had been working on it since early 2009, and it had seen a fair bit of work. It began as a rake 'n' ride that got wet and muddy in the spring. We benched it and made it worse, turning the section into a swamp for 2-3 months! We had looked at a number of options, including gravel fill [no], rock armouring [ideal] and harvesting deadfall from the area [okay] in addition to using treated lumber. A re-route was a poor option, as it would require a long, steep climb or force people through even more mud. Overall, the site was a pain in the buttocks, with running water from a seep working its way through the middle and around a big pine at the start. The area by the tree dries out relatively quickly in the spring, but the middle doesn't. There are quite a few big roots from the pine that I didn't want to disturb.

    Step 2: design + materials
    I didn't want to drive posts into the ground because of the depth of organic soil [several feet] and how wet it is. I didn't think any wood would survive long in that environment. Also, there was no reason for the structure to be elevated. This was not a stunt. Low rise meant no guardrail, further simplifying it. Since running water would need to pass under the structure, I couldn't lay the stringers directly on the ground [they would block the flow], and by keeping them away from water I'd extend their lifespan. Also, keeping the stringers off the ground meant that I would have to dig out fewer roots. A footing would be needed. I settled on treated 4x6 lumber. Our forest consists of pine, aspen, spruce and poplar. None of these is particularly rot-resistant, and I am not particularly skilled with a chainsaw, so store-bought lumber was a better solution.
    The footings are 4x6 lumber, all 32" in length [3 footings from a 8' long piece of lumber] and pinned to the ground with 2' long pieces of galvanized rebar. Holes for the rebar were pre-drilled at opposing angles to make it more difficult to pull out of the ground. All the footings were leveled before being pinned in place, in turn making the stringers [mostly] level.
    The stringers are 4x6 treated lumber in 8' lengths. They are oriented with the long axis vertical to support more load [something like a 1200# point load in the middle of an 8' span will produce 0.25" of deflection]. The stringers are fastened to the footings with 10" ardox spiral spikes, the stringers pre-drilled to prevent splitting.
    Decking was donated, but I had to promise not to say from where. It's 3" thick rough cut slabs of spruce, 12" wide and variable length, from 2'8" to almost 4'. Kept in place by 6" ardox spiral spikes. [wife's hand for scale]



    Step 3: construction
    Getting the materials to the site was a complete ******* ******. Next time I'm renting a helicopter.
    Onsite construction required a bit of improv, but went off largely as expected. A few small roots needed to be removed near the pine tree, but for the most part I just had to scrape away a flat spot for the footings, get them level and I was off to the races. The footings are around 88" apart [OC], allowing for overlap with the 96" long stringers. Gaps between the decking are generally 0.5"-1.0".

    The big question is, "Will this boardwalk last?" Tough call. The decking is crazy thick, essentially a 4x14. It's out of the water, it's away from the dirt, so 10+ years is likely. We could put some organic weather sealant on it to keep the rain out, but I don't know that it will help that much. The stringers should last even longer. The footings won't last forever, but they're on the ground instead of in it, and in compression instead of tension or shear. Fence posts of the same material regularly see 20 years, so I'm hoping for at least 10. The average load on this thing is a human, typically under 250#. The trail is not that popular with horses, as it's tighter than the riders like it. It does get some cows, but not that many. The small bridge we built using similar techniques has survived for 10 months without so much as a whimper, so I'm feeling reasonably confident.

    A few pics:
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