Radial pleated tensile structure

Radial pleated suspended tensile structure

This model was constructed from a single flat sheet of polythene.

Radial pleated suspended tensile structure

I left the model up over night. There was a storm - and it rained quite a bit.

This explains the water and condensation all over the model in the photographs.

Showing the blunt pleats

The model makes use of the idea of blunt pleating.

Part of the reason for building the model was to explore how the idea worked in a real tensile structure.

I wanted to see if the blunt pleating had much effect on the model's tendency to exhibit second-harmonic diaphragming.

I was also interested to see if it kept the fabric in contact with the cables more effectively.

I was quite happy with the results.

Eyelet

Eyelet in action

These photos show how I reinforced the fabric at the eyelet insertion points.

Construction mistake: little eyelet reinforcement

My cable arrangement resulted in direct outward forces being applied by the wire to the eyelets.

One of them was ripped out of the fabric as a result.

The cable arrangement I used was nontheless quite attractive in other respects. In future models I expect I will deal with this issue by reinforcing the fabric more around the eyelets - and all along the structure's edge.

Construction mistake: incorrect eyelet placement

One of the mistakes I made during construction involved placing the lower eyelets too low.

That created these stress marks in the resulting model.

I should have made the holes for the eyelets higher up - or else elevated the apex of the structure more - to deepen the pleats.

Construction mistake: building on stony ground

Knowing I wanted to use gravel to weigh down the edges of the fabric, I chose an abandoned railway line as my construction site - since there was plenty of free gravel there.

However, the ground was like rock - and most of my tent pegs failed to penetrate it.

As a result I wound up using these lumps of iron as ground anchors.

They were pretty poor at playing this role.

Gallery