City hall gets a lift

Photos by Creig P. Sherburne

ATASCADERO — A 100-ton crane came to Atascadero and lifted a 54-foot elevator jack into Historic City Administration Building on Tuesday morning.

Bernards Construction manager Dan Huff said that the way a hydraulic jack elevator system works is that the piston lives in a hole under the building. When somebody wants to make the elevator go up, oil is pumped into the jack’s casing, pushing the piston — and thus the elevator — up.

Since the equipment has to live under the elevator car, a 55-foot-deep, 18-inch-diameter hole was dug directly under the elevator shaft. The casing actually hangs from a super-reinforced area at the top of the hole.

So how does one get a 55-foot hydraulic jack into a hole under the city administration building?

Through the roof, of course.

Santa Barbara-based Specialty Crane and Rigging brought out a huge crane with a support truck to lift the 55-foot jack piston into the building through the roof. That put the top of the casing approximately 110 feet above the ground, at its highest.

Republic Elevator Company Construction Manager Glenn Gammons said there are other types of elevator systems, but this one was chosen because it represented the best value and smoothest ride.

“It’s about as [tall] as we can get,” Gammons said. “The old city hall had [an] electric traction [elevator system] — it’s never had a hydraulic jack piston in it before. The reason for doing this is to get a smoother ride and a better functioning elevator.”

A modern electric traction system uses pulleys and cables to lift an elevator car, and requires a lot of equipment to live on the roof. Because the rotunda’s roof is a round work of art, that option was out from the get-go.

Another option involving counterweights may have been used, but counterweights take up room inside the elevator shaft.

Using the piston, Gammons said, allowed for a larger car. Besides, he added, counterbalance systems cost more.

And a larger car was obviously a priority. The old elevator was little bigger than a telephone booth and was not ADA-compliant. As part of the construction project, Huff said, the elevator shaft itself was widened, allowing for an ADA-compliant car.

Lastly, Gammons said, the jack piston system is extremely robust. He said that he knows of similar systems that are still in use after more than 50 years. And since so much work is taking place in, on and around the building, a robust and strong elevator was a must.

“There’s no reason for it not to be there for a long, long, long time,” Gammon said.



For the complete article see the 06-27-2012 issue.

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