Adjusting a Suspension Bridge Deck

One of the hazards of building a bridge in the woods is that there are trees in the woods. And trees sometimes fall. It was only a couple of weeks after my bridge was completed that a tree fell on it. It bounced off without causing damage other than a dent in a deck board.

A couple of years ago during a flood, a tree next to the bridge came down, and while not actually falling on the bridge, parts leaned heavily on the suspension cable. I cut off the branches that were in our way and let the rest stay for now since I was busy with other projects. This spring I finally cut the rest of the tree that was affecting the bridge cable. I knew that the deck had sagged a bit and would need to be adjusted at some point.

TreeBridge

That’s why I have turnbuckles installed on all the deadman-to-post cable connections as shown in my book, Building a Small Cable Suspension Bridge. I could just turn them to pull the posts back and level out the deck again.

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I used  what was handy to provide a resistance (something to work against) to turning the turnbuckle – in this case a big stick and a metal pipe.

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WD40 oil worked to loosen up the connections. They weren’t rusty having been protected under the cover of those white tubes all these years, but they didn’t want to break loose easily.

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I used a small bar for turning, but a longer one could have made things easier.

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I used a pencil mark to verify if I was tightening or loosening.

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Once they broke loose, each turnbuckle turned easily.

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Jeep seemed amused that one side was now lower than the other. But that’s just part of the process!

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I worked on all four turnbuckles, using line of sight to achieve the results I wanted.

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All done, until the next tree takes a dive into the creek and the bridge is in its way.

This all only took about 30 minutes. Here’s a movie of the process if you’ve never seen a turnbuckle in action.

Thanks for stopping by! Be sure to check out our suspension bridge book. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2017 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Zip Line Challenge

My spousal unit, who actually writes this blog, is an author and illustrator of books for kids. She ran across this website for aspiring engineers, and thought it would be interesting to some of my readers. DiscoverE (formerly the National Engineers Week Foundation) helps to unite, mobilize, and support engineering and technology volunteer communities. They hope to increase the collaborative footprint in K-12 education and celebrate with the public as it discovers the value of engineering education and careers.

zipline

I was especially intrigued by their Zip Line Challenge for kids. It’s actually a model that challenges kids to transport a ping-pong ball down a zip line from start to finish in 4 seconds or less. The activity discusses many of the considerations when designing and building a zip line. I’ve uploaded the PDF so you can download it from here, or you can get it from the website listed above. There are a lot of other creative engineering related activities there, all free to download and use in your classroom, home, summer camp, whatever.

Check it out: zip-line-challenge_091316

One of these years I hope to finish my zip line. All is ready, but now the brush has grown up so much I have to hire a tree climber to clear the 420 foot long pathway.

ZipLanding

View from the zip line tower to the landing 420 feet down the hill.

Thanks for stopping by! Be sure to check out our bridge book if you’re thinking about a DIY suspension bridge. Here is the link: Building a Small Cable Suspension Bridge with the Cable Locking System.

And if you’re curious about Robin Koontz’s books, look her up on Amazon as well: Books by Robin Koontz

Images, diagrams, and text copyright 2013-2017 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Photographic Journaling

I’m not exactly someone who keeps a formal journal, but I keep a lot of records. They are for reference or just as a way to look back and remember what I did that day, that month, that year.

One of the many helpful advantages of digital photography is the ability to take and store photographic records. It’s easy and virtually free, once you have the device, to document and store the process for any project. Publishing the book Building a Small Cable Suspension Bridge was an afterthought after I finished building my bridge, but luckily my spousal unit had recorded most of the steps, using our first digital camera. That old beast used 3-1/2 inch floppy disks (remember those?) and the photos were low resolution. But with some computer magic, we had enough photos to chronicle the steps I used to construct the bridge. Many photos were taken just for fun and our own life journal, but others were for reference.

OLYMPUS DIGITAL CAMERASince my first bridge was a “Golden Gate” style suspension bridge, the stringers were of varying lengths with obvious repeats on each side. I installed the connection “eyes” to the stringers and organized them using a numbering system. That way, when I attached them to the two main cables, it was an easy chore to sort and install, using cable clamps.

I assembled everything on dry land. Then I just attached the two cables (with stringers attached) to the four posts. I could then easily install the cable locking system components and the decking.
StringersPasture
My more recent project is our house. I put in a lot of blocking so that there were plenty of places to connect cabinets, towel racks, grab bars, whatever. Then I photographed all the walls before covering them. That way, when it was time to hang cabinets, I referred back to the photos to recall just where I put the blocking.

This photo shows the backside of the kitchen wall with blocking for the cabinets. My only regret was that I didn’t write exactly how far the blocks were from the ceiling or floor – large lettering would be easy to read in a photo – but I was able to locate them pretty accurately using my electrical boxes for reference.

blocking

Thanks for stopping by! If you want more information about my bridge, you can view a video and also read through the archives of this blog. If that’s not enough, be sure to buy my book! Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2014 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.