Surgical touch for demolition
When it opened more than 40 years ago, Medical Towers North was a distinctive new presence on Louisville's skyline.
As the city's first "curtain wall" building, its bright blue porcelain-covered exterior panels, hanging from an aluminum grid on the eight-story structure, added "a note of cheer to the otherwise drab surrounding area," a 1963 advertisement said.
The ad praised modern features including air conditioning and a parking garage that could double as a fallout shelter. But today the medical office building at Floyd and Gray streets is out of date, and its owner, Norton Healthcare, is taking it down so a modern replacement can be built.
The demolition poses special challenges because the building is surrounded by hospitals, meaning Norton must remove the structure without spewing dust and mold around the downtown medical center.
And there can't be falling debris because of the many people who walk or drive past the busy medical corner of Floyd and Gray every day.
In addition, the job must be done without the vibration that would be caused by conventional demolition techniques, because the building's foundation is only a few inches from Norton Hospital's surgery suites. The operating rooms stretch underground about half a block from the hospital's above-ground footprint, butting up against the basement of Medical Towers North.
"Surgeons don't like vibration. A lot of them are doing some really delicate work," said Shawn Brinley, president of HCL Inc., contractor for the demolition.
For those reasons, the project is destruction with a gentle touch.
Norton put together a game plan that includes vibration detectors, daily air sampling and erecting a 42,000-square-foot black screen around Medical Towers North.
Louisville-based Micro-Analytics supplied vibration-detecting equipment and services, while Environmental Safety Technologies, also of Louisville, is doing the air sampling to gauge levels of dust particles and mold that might be stirred up.
"The goal of the project is to minimize the dust … so that it doesn't flow into other buildings" where patients might get an airborne illness, said Shauna Weis, president of Environmental Safety Technologies.
The black screen also sprays a fine mist to knock down any dust that is stirred up.
Instead of toppling the building with a wrecking ball from the outside or imploding it, which would create noise, vibration and dust, Brinley's crew is taking it apart bit by bit from the top down -- a process termed "deconstruction."
Machines with pneumatic claws crush the building's concrete frame into football-size chunks, which are dropped down an elevator shaft onto a bed of sawdust placed there to dampen vibrations.
The plan has worked so far, said Betty Bradford, director of surgical services for Norton Hospital.
She said detectors in the surgery suites are set to automatically telephone construction supervisors and order them to halt work if vibrations reach a certain level. That hasn't happened, she said. "We're just business as usual down here," Bradford said.
The black screen was placed around the building a few weeks ago. As the upper floors of the building disappear, the screen will be gradually lowered toward ground level.
Perhaps next month, the screen will come all the way down -- "and just like David Copperfield, (the building) will be gone," said David Boome, Norton director of facilities planning and construction management. "I want it to be a non-event."
Last weekend, traffic was closed as a pedway above Gray Street -- between Medical Towers North and its sister building to the south -- was removed, cut up and hauled away. The pedway was a link in a system of overhead walkways connecting Norton's downtown health-care buildings.
To prepare for its removal, Norton erected a new pedway alongside its parking garage between Floyd and Preston streets -- preserving an overhead path from the company's Chestnut Street hospitals to Norton Healthcare Pavilion on Broadway.
Norton has been planning the project for two years, Boome said. It's expected to be completed by the end of next month.
The project is the first phase of a plan that also will replace two other buildings by about 2010 -- Medical Towers South and a red-brick building on the southwest corner of Floyd and Chestnut streets.
Most of Medical Towers North will be recycled.
"The thing that used to happen is that contractors would knock the building down and then haul it to a landfill. But times have changed," Boome said.
HCL plans to recycle about 94 percent of the material from the building -- ceiling lights, plumbing fixtures, aluminum, steel, even drywall and concrete, Boome said. Some fixtures will be taken to Chicago for sale to "re-use" stores, Brinley said.
The recycling is not only environmentally sound, but economical. It will save Norton about $25 a ton in landfill fees, or more than $110,000. The building weighs an estimated 4,800 tons.
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