South Loop Climb Reroute Project (Wood Berms out the Wazoo)
Below is an overview of the structures we have received approval to build during the reroute of the steep south loop climb at Illiniwek. The IFP Ranger actually suggested using wooden structures because they are less disruptive to the local soil, plants, and hydrology.
What is going on?
We are currently in the process of rerouting the steep climb on the south loop of the park (reasons listed below). The new dirt trail has nearly been completed and we are now moving towards building the structures necessary to span drainages and make sustainable, low impact, and fun turns.
Map of new trail and feature locations. Click to enlarge.
The Structures
(1) Elevated Turning Platform with Berm
This design is an alternative to a switchback style turn like we built on the north loop two years ago. This method allows a larger turning radius (11-16 feet vs. 7 feet) and will provide a better riding experience. The berm doubles as a guard rail allowing a taller/wider structure while still factoring in user safety. The bent deck planks will allow this feature to be ridden at any speed and will eliminate a harsh transition between the deck and berm. This gradual curve will also reduce the amount of debris (leaves, dirt, etc.) which can collect on the structure and promote rot or increase the chance of washing out a tire.
Basic construction consists of 6x6 posts joined to create piers, triple 2x6” deck stringers spanning between piers for the under structure of the deck, and rough sawn white oak decking (1.25" thickness). Treated dimensional lumber will be used to provide longevity especially where wood/dirt touch. The deck and foundation is designed to handle a combined load of 100psf which is typical for high use trail bridges.
Deck planks will be steam bent off-site using a steam box and bending jig to repeat the same 2’ radius curve along the entire length of the deck.
(3) Wooden Ground Berm
Similar to the berm on SBP's Jubilee trail but will span 180 degrees with a radius of 11 feet. This berm will also feature bent decking planks to suit riders of varying speeds. Treated 4x4 posts and 2x6 & 2x4 stringers will make up the underlying structure.
(4) Boardwalk
This 40’ boardwalk will span a seasonally wet area. The posts for the boardwalk were installed on 10/21/14 and are made from locally harvested black locust (a very decay resistant wood). Treated 2x6 stringers and rough sawn oak decking will finish off the tread area. The boardwalk will feature a slight bank as it rounds a corner and some undulations along its length.
(2) Small Berm Bridge
This bridge spans a small drainage (~10’ wide) and will mimic the design of the other structures but on a smaller scale. Treated 4x4 posts and 2x6 lumber will be used for the structure with rough sawn oak decking.
What is needed to complete this project?
I will be asking the FORC board and membership at the November meeting to approve as much funding for this project as is feasible given our current finances. I will have a price estimate/bill of materials ready for the meeting. We probably won’t have enough to cover all of the costs at this time so we will need to find more funding or material donations to make up the difference. I have found several grants that could help with this project but we are currently ineligible since we are not a 501c3 non-profit organization. I also asked Illiniwek for help but they have exhausted their yearly discretionary spending and could not contribute other than on-site materials and some labor. If you know of any businesses that would be interested and able to donate funding/materials for this project please let me know (send me a pm).
I have a source lined up that is willing to sell us treated posts at near cost and help transport materials for the price of fuel and another source that can supply rough sawn decking at a very reasonable price. A source for fasteners (timber screws and decking screws) would be very helpful because we will need a lot of screws. Also looking for a supplier of treated dimensional lumber.
When will this project be completed?
It would be great to have this project finished by early spring and ready to showcase at the 2015 Illiniwek Abermination race. This is doable given we can obtain the necessary funding and materials. Below is a rough time line which will make this possible:
- Setting all posts this fall before the ground freezes (usually late Nov.)
- Building the understructure and installing decking over the winter/early spring
- Rehabilitate the existing section of replaced trail as soon as the new trail is opened (spring)
Why is the old trail being rerouted?
This section of trail averages around 20% grade for the initial climb. We have a hard time keeping local soils in place on anything steeper than 12% and if we do nothing this trail will eventually turn into a large incision in the slope. It is already at the point where erosion is accelerating rapidly and as time progresses will get much worse. The amount of work needed to correct it now will be much less than at a later date. The steepness also poses a safety concern because it is not possible to quickly stop a bike while descending and poor sight lines exist along much of the steepest sections of trail. We have already had multiple reports of user conflicts in this area and are working to address this issue on the trails.
When can we start?
We have already started on a few minor projects in this area. Most of the new trail has been dug in and posts for the boardwalk are installed. Once we get the required materials for the structures we will resume trail work days to begin construction. The dates are currently unknown until funding has been secured to purchase the materials. Stay tuned for updates and project announcements.
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