Kennelly Bridge Complete!

The bridge at Kennelly Forest in Dublin was completed about a week ago!  This bridge has been a complicated project from the beginning, as we realized that in order to span this extremely flashy stream we'd need a bridge that was roughly 30 feet long.  The previous bridge was a drawbridge that was set low to the ground- a good idea to be able to lift the bridge before large storms, but it still blew out in a large rainstorm, so we knew it's replacement would take some consideration.

Some of the core bridge crew, on the finished bridge

Since lumber is not readily available in lengths greater than 20' and there were no suitable trees to cut for bridge stringers in the immediate vicinity, land steward Bart Hunter came up with a plan to create spliced stringers of appropriate length out of pressure treated lumber and laminate pieces that were staggered, glued, and bolted together.  Stringers made this way have been used in timber bridges for a long time, and are generally as strong as solid pieces of wood; however, we'd never tried to make a bridge like this before! It was a learning process for all involved. 

The abutments for the bridge were also a challenge, as we needed to raise the bridge a good 3 to 4 feet above the stream to be safe from rising water events.  To do this, the bridge crew created wood cribs out of large pieces of 12"x12" lumber, and filled/pinned them in with boulders.  Getting these abutment pieces across the stream required a griphoist (trail winch) and a high-line system that was used to ferry pieces one by one across the water.  It was slow going but worked extremely well.  The highline was also used to move the bridge stringers into place.  Finally, the decking was added, and then a railing.

High-lining a stringer over the water

All told, we estimate that the Kennelly bridge involved well over 300 hours of volunteer power!  Many thanks all the volunteer land stewards who worked on this project, espeically Bart Hunter, Walter Weeks, Alan Cort, Hiel Lindquist, Ray Jackson, Mark Kresge, Ruth Ward, and Karl Putnam.  Amazing work everyone!