Boogie Man Trail Day #2 – Building A Ladder Bridge

by | Jun 26, 2011

Time for some love. Broken and rotted rungs stop the flow of a trail. 
We spent this June NSMBA Trail Day to fix one of many damaged structures

 

Anyone who regularly rides on the North Shore trails will agree that ladder bridges are an integral part of our trail network. We use them to connect sections of unridable trail, to ride over mud bogs, streams, fallen trees, and across ravines, not to mention to reduce erosion in sensitive environments. In the case of Boogieman there are numerous sections that require a bridge to complete parts of the trail. We selected one bridge in particular that was becoming unsafe due to rot and did not have a ride around as an option. Our focus: to re-build a new bridge that was safe, would sustain at least a decades worth of mountain bike traffic, and use all lumber from the surrounding forest that was dead fall.

Clearly this ladder bridge was in need of replacement.  Not only missing rungs, the stringers were rotted through and the supports were not secured to anything structural

 

This before shot shows how the roll out ramp had an interesting twist from rotting logs, 
destined to take out a rider upon exit at some point.

 

    

    
Sean Gerke our Trail Maintainer with his old friend "The STIHL 20" MS260 Chainsaw.
 
A thing of beauty, especially when it's a tool you really need. On this trail day, Sean certainly used it a lot. It's amazing how versatile and essential a tool the chainsaw can be. It was used to cut down the old rotten structure, cut supports to size, create the notches in all the beams and brackets, and prepare the rot resistant cedar logs that were to be turned into fresh ladder bridge rungs.
 
Simple bucket? Something so basic is the life blood of how the crew moves dirt from the source (trail side dirt pits carefully selected to fill in erosion from prolonged trail use). Again, this tool is an essential item on trail day! I couldn't imagine being without this sturdy pail! Listen to me, I am a changed man!
 
Dave Nordman wielding the precious pick used for loosening up hard ground
 
The day started off with a 30 minute hike in, with all the tools, food and water for the day. It has to be said that hiking in with an armload of tools is a lot more challenging than you expect it will be. Shovels, pics, buckets, nails and a chainsaw aren't exactly designed for hiking. Regardless, they sure are essential to the job and worth packing for the journey!
Here Sean bucks down the old structure with the gurgling, smokey monster. 
Then we pile up the debris of the old dead structure to a final resting place, out of eyesight of the trail
 
Sean gave us an interesting lesson on how to create the plank rungs in 2" and 3" thickness for different uses. The mini sledges and wedges split the cedar beautifully with the natural grain creating the perfect rung almost every time. As an aside, Dave cut a few thin planks for his barbecue to make salmon taste extra cedar flavored. I was impressed by his cultured palate.
 
Sean in his protective gear required for such plank making procedures.
 
Dave Norman with a big stack of newly created cedar rungs. This burly lad was of great help! Cedar is the best choice for rungs not only because it is naturally rot resistant but also provides good traction even when wet.
 
Jake and Sean plan out the structure install with the trusty tape measure in hand
 
Skilled trail builder Jake Stein (above in red hat) helped us out for the day, handing down some valuable knowledge to the wide eyed onlookers. Here he and Sean measure up the length of the stringers required and plan the new support post hole locations.
Measure twice :: cut once. Words to live by
 
Support posts are installed by Jake and Kim, after the painstaking process of digging in the mountain dirt.
 
The ground is quite diverse when it comes to what is below the surface. I knew it was a flip of the coin how challenging it was going to be to get a 3 foot deep hole dug for the support posts. These posts were essential to the stability of the whole structure so we dug and dug until we reached the required depth. Yes we hit a lot of rock, roots, and clay, but with the searing arms shoulders and back we managed to get them installed. Jake knew all the tricks to get past the hard earth. We used the bio mass (dirt) to fill in the new landing pad.
Filling in the remaining space around the post with rocks and dirt made it concrete-like sturdy and an anchor of the structure.
 
 
The 9 foot long support is lodged a deep 3 feet below the ground to fulfill the 1/3 rule on a structural post. We filled in the space around the post with rocks of various sizes along with dirt to create a concrete like sturdiness.
This custom cut little gem sat right on the top of the support posts 
to hold the stringers in place for the top ladder as well as the descending ramp. 
Another example of how handy a chainsaw comes in on trial day.

 

The upper part of the structure was itact and in good condition but we had to reinforce the ground around it and install a more solid cedar log. Andrew and Jake build up the sides of the log with rocks and dirt to stabilize as Sean was preparing a skilled cut with the chainy.

 

It was an interesting artistic maneuver Sean had to do to cut the notches for the stringers with the chainsaw.

 

These cedar posts are not only rot resistant but they are beefy and are well supported at both ends. Unfortunately I didn't get a photo of how we supported the bottom of the ramp with rocks beneath a cedar log. We filled the landing area with a thick layer of packed in golden dirt with a rock layer beneath for erosion resistance.

 

Sean empties his Dakine nail pouches, bursting with 5"-10" galvanized nails, to fasten the rungs to the ladder.

 

Andrew pins the bridge together with the long spiral galvanized spikes, using the weighty sledge

 

Man! These nails make a lot of resistance going into the cedar logs! They are seriously securing the position of the structure!

 

art of doing trail work and rebuilding is the clean up of the area and stacking unused wood for future use. Here Sean stacks up the extra cedar ladder bridge rungs created by Dave and Andrew. We will make some use of those on our next trail day on other structures further down the trail.

 

Before the tear down and rebuild :: Ultra rickety ladder bridge structure needing some love.

After :: The new structure with a nice pile of golden dirt in the landing zone ready to be ridden for years to come!

Note: After the trail day, I was exhausted… and I mean speechlessly exhausted. I have run marathons, and have done a whole lot of bike races, but nothing compares to the last couple of trail days on Boogieman. The work we have done is not even a sliver of what some trail builders have spent years and years doing. This stands as a reminder for every time I enter a trail that has been built and regularly maintained and a reminder of how much painstaking work went into the trail. Hats off to the trail builders and trail maintainers of the shore! You guys are my heros! Without you we wouldn't have these experiences! Thank you, thank you, thank you!


-Kimbo