Book-inspired Suspension Bridge in Virginia

We were delighted to finally receive photos of a suspension bridge that was inspired by our book, Building a Small Cable Suspension Bridge With the Cable Locking System.

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According to the builder, Mo Goldman, the bridge is just under 40′ feet in length and 4′ wide (basically half the length of our bridge) and is located in Virginia just outside of Charlottesville.

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The posts are aluminum, 13′ in length, 6″ round with 1/4″ thick side walls, easy for two guys to carry. The post holes are 3′ deep and about 2′ around; the posts are placed on a concrete footer prior to pouring around them. Everything was hand-dug and poured because they were limited to access with a Polaris on one side.

It was fun to see that Mo set up a temporary cable to move materials across. That’s how we moved our gravel for the opposite side, one bucket at a time. But Mo took it further and carried the posts, other materials, plus wheelbarrow and even himself across their “zip line.”

SetUpStringers

Mo also followed the idea of setting up the catenary curve between two trees/structures located away from the creek to plan and build the cables and stringers on dry ground.

MoGoldman

Mo didn’t use our cable-locking system, but instead used a system often used for this type bridge – an appropriate length “eye” bolt placed in a drilled hole in the beam. The suspenders were then connected with a chain connecting link, which uses a threaded portion mating to a free spinning nut to open or close it.

He wrote to us about the bounce in his bridge which was more than he expected, though not a big deal. I noticed that he paid attention to harmonic resonance in the arrangement of the stringers so they were assumed off the “nodes,” so wondered if the decking material he used could be partly responsible (a suspension bridge is going to bounce, that’s a given). He used a material called Trex, which is a deck material made from recycled plastic and wood fiber. Trex tends to flex more than standard lumber does. We concluded that he needed to stiffen the deck, so now he is working on some ideas.

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Mo even put up a sign on his bridge similar to ours and inspired us to remake our sign so that it names the creek, too. We hope others who build a bridge based on what we did will also send us photos and notes about their building experience.

Meanwhile our book is available in paperback and as an ebook via Amazon.com.

 

How to Build a Small Cable Suspension Bridge

INSTRUCTABLE-BRIDGE-LOGOWildcatMarvin

As mentioned, we built this bridge and wrote a “how we did it” book about the process a few years ago. Recently, I thought it would be fun to share the basics of this design as an Instructable for people who have enough skill to be able to take the information and work with it. And as we do in our book, we recommend having your specific design approved by an engineer just to be on the safe side.

Here is the link: Building a Small Cable Suspension Bridge – the Basics Plus a Video Demo

I entered their “Outdoor” contest and you can kindly vote if you like by clicking the little vote button at the top of the instructable page. Thanks! I need a t-shirt.

UPDATE: Thank you for your votes – were a winner! We won a t-shirt and a waycool  Campstove 2 from BioLite Energy!

BridgeWin

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.