For my main semester project, I am going to be building a ‘tensegrity’ base for a coffee table. A ‘tensegrity’ design is a tension-based structure that creates a sort of floating illusion. These designs operate on the principle of opposing tension to create stability. A lot of the designs that I have seen out there seem to be very wobbly and/or crudely but together. To a certain extent this wobble helps to sell the illusion of the floating top, and for the purposes if this project, this is what makes the design dynamic. That being said, I am interested in creating a high-strength, high-tension design which maximizes stability, while remaining elegant and refined, and also retaining this floating aesthetic.
The focus of my project will be on building specifically a steel base, which will have tabs to attach different table tops and under storage facades (framed within the steel). Depending on how the base comes out and how much time I have left when the base is completed, I will either throw on a table top that I already have or just make a new one.
My general design will follow a similar form to this crude prototype I made a while back. Basically, there are two identical bodies which are attached via 5 cords (4 cords at the corners with opposing tension to the fifth cord in the center).
For the structure of the base, I will be using 2”x2” tube steel to create the 2 identical bodies. For the high-tension cords, I will use 1/4” braided steel cable, tensioned using high-strength turnbuckle tensioners. As an upper limit for the maximum tension on each of the 4 corner cables, I have chosen a 500 lb cap, translating to 2000 lb of tension on the center cable. In reality, I would expect to put closer to 100 or 200 lb of tension on each corner cable, but to be safe I will be working with a steel cable which has a breaking strength of 6000 lb (3 times that of the theoretical maximum). I have also done some preliminary defection calculations, using the theoretical maximum tension values, to make sure that the bending forces will not cause deformations of greater than 0.1” in the tube steel.
I am looking forward to finalizing my design and getting the process started!
Here are a couple more preliminary sketches for reference.
Image Sources :
My Modern Met, 29 July 2020, mymodernmet.com/john-malecki-floating-table/.