Historic Swingamabob

by Don Friedman on March 11, 2016

I expect to see really weird things in buildings on a regular basis, and am never disappointed. Today’s really weird thing comes from one of Marie’s site visits:

Hanging Tank 2

Water tank in a sling! Four slings, actually. Here’s another view:

Hanging Water Tank 1

It’s rather elegant: a steel strap as the sling, connected by clevises to hanger rods with turnbuckle adjustment. But why? It’s just a water tank so there’s no need to protect it from ordinary building vibration and movement, assuming that the sling support even does provide such protection. Besides, most water tanks in New York are wood, and this riveted-steel tank is already more far robust than that average.

The outside view of the tank penthouse may provide a clue for a partial answer:

Water Tank Enclosure

The only rational reason for the penthouse columns to be splayed outward like that is to get the load directly onto main building columns below the roof. So the splayed columns and the slings may be part of the same idea: the tank is very heavy and must be supported directly on the building columns rather than on the roof slabs and beams. The reason this is only a partial answer is that the same goal  could be more simply accomplished by using dunnage beams above the roof, supported by stub posts directly above the main columns.

We’ll never know why.

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