Repairing an Alaska Footbridge using Linear Actuators
Channel: Orion Lawlor
Date: 2020-05-19

I use two linear actuators to push my wood footbridge back together in Alaska.  The bridge spans a 25 foot (7.6 meter) gap, over a small creek that tends to build up a lot of ice.  This winter the weight of a thick layer of ice building up from the creek (about 6 feet / 2 meters below the bridge) broke the bridge's wood in several places.  (The bridge design is almost all 2x4s but can span a very long distance for foot traffic, leave a comment if you'd like to see a video on the design!)


I used linear actuators, which work like hydraulic cylinders moving in and out, but are powered by DC electricity, here 12 volts.  They're around $50 each, but last for many projects, and seem incredibly strong for their weight and price.


I glued the broken bridge pieces back together, and used the linear actuators to push the parts of the bridge back into a straight line.  I left the linear actuators pushing up on the bridge until the glue cured, and the repair seemed to work.


CAUTION: whenever you're jacking things up, there are lots of ways for the whole thing to go sideways--literally!  Work safely, the force of a jack is enough to make a big mess of you and your project.