Thread: Documentary - The Making Of "Puff of Wind Sculpture"
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Old December 25th, 2017, 11:57 AM
Asher Kelman Asher Kelman is offline
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Originally Posted by Peter Dexter View Post
Hello Asher congratulations on the commission. My impression is that the "sculpture" begins at the boat and goes up from there. All the "structure " below may be practical but is aesthetically extraneous. In future designs you might think about designing the work so that the necessary structural support is aesthetically and visually integral with the work. A well known sculptor who comes to mind who achieves this and who has also employed bearings to achieve movement is Mark Di Suvero.
Well, Peter,

Your artistic intuition and tastes serve you well. The original design was a simple hidden anchor in the ground, but the City required the sculpture to be housed in a concrete pot with a hole for a 6" steel pole.

Asher Kelman: "Puff of Wind": Original concept

Asher Kelman: "Puff of Wind": 3 Stripe Sail

Asher Kelman: "Puff of Wind": Design in Required City Pot

Nothing could be anchored. The engineering challenge is the potential wind load on the sail. That was reduced sufficently, for local conditions with the deisigned holes for wind to "escape". So we easilly covered the requirement of winds of 80 pph. Still my own obsession for safety was isolated. Although in submitting the sculpture for competition included the input of the City Engineer, I asked and was told it was not required as there was confidence in our own care and due diligence. During the months of installation of the 32 ft high structure, there was awe and excitement but no requirement for a deputy inspector to hound me at every step as in building a building. So I became my own bad-arse site supervisor. I brought over our stuctural engineer to confirm the torque force used to tighten main supporting bolts were at the exactle the required force, using a calibrated torque wrench that "breaks at the prescribed torque. I also set up a cable tension testing laboratory calibrating our cable tension instruments, to be certain we measured the tension of the cables in the sculpture accurately. So we had that covered too.

At that time, there was, not yet any formal requirement from anywhere in the City to confirm our calculations. It meant I had the personal responsibility to be far, far cautious and safer than expected. Such extraordinary caution led to time delay as I wondered about all possilbe, even rare or preposterous risks of nature of vandalism.

I discovered rare historic winds of 100 mph, in the 100 years ago, elsewhere on the California coast! For me, we needed to go far above that very rare event that had never occurred on our region of the Coast. My decision, meant further stringent checks on our engineering. I set myself very high standards. I would not do the welding. All welds were done by certified industry workers with years experience in heavy steel fabrication. I desired to be assured of safety, even when neighborhood roofs were torn by the wind. State equirements are for 80 mph. We aimed for 160 mph and ended iup at 214.7 mph. We assumed a worse possible case, of maximimum load, when the rotating sail was 90 degrees to the wind, but both safety mechanisms of the bearing assembly were imagined to be frozen. The latter is vanishingly unlikely, as there is no freason for them to get stuck anyway.

After the sculpture was essentially complete, The City hired a wonderful new head of engineering and eventually, the City required of itself to get a permit! So I assembled 3 books of plans and engineering calculations and waited for approval. Meanwhile the area of the sculpture was roped off with police tape for months.

The plans went out for outside engineering evaluation and came back approved. But we asked to add a safety railing and a bar, 6' above the ground to comply with the cane locating-requirement for sight challenged individuals. So we had to go back to the drawing board, and figure out how to add the requested rails without damaging underlying concrete by a single hole. That delayed us further and then months more as we had to fabricate, sand blast and powder coat and install the required safety system.

Asher Kelman: Puff of Wind Sculpture Installed

City of Manhattan Beach, California 2017

In a final setting the sculpture will not have any such pot and railings below but a tall column fixed in the ground. So it will return to the original imagined vision!

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