Replacing the Post on a Small Cable Suspension Bridge

As you might remember, February 25, 2019 was a bad day for our 80′ suspension bridge that we built in 2005. Part of a large maple tree weighted down from heavy snow decided to break and fall directly on one of the support posts on the other side of the creek, bringing lots of other trees with it. Once it thawed and we could get someone over to clean up the mess, we assessed the damage. We had to replace the post, which involved many steps, and most of the decking. Also, we had to raise the bridge again.

We lined up a contractor and a crew to do the work with Marvin’s supervision, but they were busy and having a hard time fitting us in. Summer came and went, and when the rains started this fall, we decided we could do it ourselves with help from our neighbor (and plenty of beer!). We are not as young as we were when we built this bridge, but we still have the same determination to get the job done. To note, since the damage is on the other side of the creek, everything had to be done by human power and ingenuity. And did I mention plenty of beer? I think I did.

 

One of the first tasks was to dig up the old post. All went well until we realized it was buried 4′ deep, not 3′. We should have read our book! The last foot or so needed a special tool since there was no room for a shovel. The cut cake pan worked the best. Cut the pan and then screw the two halves together and we had a quick and easy gravel scoop!

We used a power pole again, though this one is pretty substantial. The end was carved for the metal collar that connects to the bridge cable and to the cable to the dead man. Holes were drilled and the raw end was treated with preservative.

Marvin had to chisel the collar off the old post, then he replaced both eye bolts, which were bent when the trees hit the post. The eye bolt for the bridge cable is 3/4″ and the one for the dead man cable is 5/8″.

The above collection of photos shows some of the post-wrangling. The two guys used a pee-vee, cables, chains, and a handy little tractor on the opposite side to get the post across the 40 foot wide creek with steep banks on both sides. There’s a movie of some of this on our Facebook page, link below. If you wonder why a lot of cable is wrapped up on the tractor bucket, that’s because we had to reel it in as the post headed across the creek.

Next, the boys built a tripod using 20′ 2x4s and installed a pulley at the top. At first they had rope to pull up the post, but it was soon replaced with cable because the post was heavier than estimated.

They used a come-along which worked to get the post raised so much, then the post had to be secured, the rope loosened, and the come-along reset. It took several resets before the post finally drifted above the hole.

 

The last trick was to center the post on the pin in the concrete pad as it was lowered into the 4′ deep hole.

The new post is in place!

It was cool to see the new post up and almost ready for the bridge deck. Next, we back-fill with gravel (by hand of course) and tamp it in. Stay tuned, and be sure to watch for exciting movies on our Facebook Page here!

Thanks for stopping by. Be sure to check out our book about building this bridge. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2019 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.