New Bridges on the Blue Trail

Bridge prefab

Perhaps you’ve already hiked across the bridges that were recently built on the Blue Trail at Adams Farm.  If you haven’t, you can now walk the entire Blue Trail without getting your feet muddy!

After several years of slogging through the mud on hiking trips and having to shed cross-country skis to pick his way on foot around the wet spots in the winter, Gary Riggott, the chairman of the Trails Committee, decided to take the initiative and build a couple of bridges for the Blue Trail.

Gary made an initial survey of the trail in February 2009 when the ground was still snow-covered, and put together a design proposal for the Friends of Adams Farm.  It described a single-span 4-foot-wide bridge for both locations, built strong enough to support a horse and rider (about 1,500 lbs). The Friends said, “Forget about the horses and just keep the bridge off to one side so horses can still pass on the trail.”

Boardwalk under construction

He next surveyed the trail in May 2009 when the snow was gone, only to find that the trail had a much greater wet area than he had realized at first.

His next design proposal had a single span bridge roughly 20 feet long on the stream closer to the big field, while the larger stream and wet area required a multi-span boardwalk close to 100 feet long!

Being a cross-country skier, Gary incorporated some design features into the structures from that perspective.  The ramp sections are long at about 8 feet.  This allows for a gentle incline that is easy to ski up and down.  A railing is included to provide extra safety in winter when the bridges may be slippery.  Lastly, he included a lower railing 2 inches above the deck in order to keep skis from sliding off the side of the bridge in icy conditions.

Boardwalk construction

The bridge and boardwalk were both constructed in the same manner.  First, concrete beams were placed on the trail and leveled.  These served as footings for the individual spans.  Their positions defined the location and length of each span.  Gary then took precise measurements between each beam.  Using these measurements, he sawed, drilled, and assembled each span inside the barn, one at a time.  He then labeled the individual pieces of each span, disassembled them, and stacked them outside the barn.

Gary built a total of 6 spans and 4 ramps.  All the wood used was ACQ pressure-treated.  This is the current chemistry used in pressure treating.  There are no heavy metals like arsenic that were used in previous generations of pressure-treated wood.  ACQ uses copper salts and is expected to last 20 years.

Finished bridge

For the bridge, the materials were hauled out to the back field on utility trailers.  From there, ATVs took them down the trail to the bridge site.  For the boardwalk,  a staging area on the Ferris property on Sexton Farm Road was used, which greatly shortened the distance to the boardwalk site.  All the boardwalk materials were carried by hand to the work site from the staging area at the Ferrises’.

A generator at the work sites provided electrical power.  Most of the assembly was done using drills, either electric or cordless.  It took four people about half an hour to assemble each span frame.  Two groups of four people then pre-drilled and installed the Trex-like composite decking material.  The composite decking material added slightly to the cost of the project, but it was worth the extra money because it is basically maintenance-free.

Finished boardwalk

The bridges were built on the first two weekends in November.  All the work was done by volunteers.  Gary’s wife Deb personally cut every single one of the 288 four-foot-long pieces of Trex that were used for the decking!  Of the 26 volunteers that worked on the project, 11 were students at Tri-County Regional Vocational Technical High School in Franklin, fulfilling their Community Service requirements.  Without their help, the project could not have been completed in just 4 days.

If you haven’t been out at the Farm and checked out the new bridges yet, head on out there and take a hike on the Blue Trail – the bridges are waiting for you!

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