Tensegrity Obelisk: Summer

By mid-summer, the morning glories had gotten dense enough that they tilted the obelisk. This revealed a disadvantage of using the weaker zig-zag design for the obelisk rather than the diamond topology. I actually didn't have much idea of how much all the vegetation would weigh when I designed the structure, and still don't really know how much it all weighed or how the weight was distributed. The other factor which I think needs to be taken into account is that the vegetation represents an asymmetric load since I would think it is denser on the side of the obelisk toward the sun. Visually the asymmetry wasn't readily apparent.

The tilt could have been corrected by retying some tendons, but that would have run the risk of damaging the vines. Not wanting the risk of having the obelisk tear up its stakes and fall into the neighbors' apartment, I secured the obelisk with a rope to the nearby stairs. Another approach would have been to tie on additional tendons to correct the tilt.