Oakville residents are cheering on the demolition of the Oakville-Trafalgar Memorial Hospital. That’s because the shiny new Oakville-Trafalgar Memorial Hospital opened across town in 2015 and the old site is being redeveloped into a community centre, park and new residential units. However, neighbours have one request: “Quiet, please.”
The city contracted DST Consulting Engineers to create a “Former Hospital Deconstruction Strategy” which was approved in April 2017. With demolition taking place in an established residential neighbourhood, noise mitigation measures included the installation of quieter broadband backup alarms.
You’re surrounded by a lot of nice houses and you’re aware that you’re working in someone’s back yard,
A typical vibration strategy would involve a video survey of properties within a 30-metre radius of the project. To protect historic homes in the neighbourhood, the video radius was expanded to 75 metres. Six seismographs were also installed to ensure vibration levels remained below 10 mm/s, far lower than the maximum allowable 50mm/s.
The demolition contract covers two buildings, an extended main hospital structure, the three-storey Helen Lawson building and a stack about 175 feet tall.
Structures in the main hospital facility range in height from one to five storeys, plus mechanical rooms and partial basements. The demolition contract, valued at $4,289,000, was awarded to Delsan-AIM, which began work on the site in August 2017.
The demolition company performed asbestos abatement using its own crews. Peak crew levels of 25 to 30 workers were reached during the early part of the project, when asbestos abatement, interior stripping, and initial structural demolition overlapped.
“The buildings looked like they were built over perhaps three periods of construction,” says Carmelo Pastore, district manager with Delsan-AIM. “Parts of the building are poured concrete and the emergency wing, for example, is made of structural steel.”
Excavators have been making quick work of the building, although the contractor brought in 65-tonne excavators with shears to chew through a two-foot-thick concrete slab underpinning part of the hospital.
The site offers a generous working space, including a large asphalt parking lot used as a staging area. However crews must work carefully around mature trees that will remain on the site.
Rules imposed by the city govern the way the contractor can operate. Work is restricted to weekdays from 7 a.m. to 7 p.m. and vehicles are carefully timed to arrive and leave through specific gates on a predetermined schedule.
“The neighbours had a lot of input into the demolition operation,” says Pastore. “You’re surrounded by a lot of nice houses and you’re aware that you’re working in someone’s back yard. You’re always aiming to do a good job, but doing it quietly.”
The demolition design also prohibits the use of explosives, so the building’s stack won’t receive a 21-gun salute as it drops.
“We’ll chip a bird-mouth notch into the base and let gravity take it down,” says Pastore.
“Just like felling a tree.”
Concrete is being crushed on site and will remain there for use in the new development. Cold weather has occasionally sidelined dust-suppressing water cannons, but crew members have filled in, suiting up in thick rubber garments and using hand-held misters.
Steel is being recycled by Delsan-AIM’s parent company, American Iron and Metals, in Hamilton.
While most residents won’t miss the building, crews have been asked for specific souvenirs.
“A lot of people in the area had children born in the maternity ward,” says Pastore. “Some of them just want a brick for sentimental reasons. One of the residents asked for a sign from the laundry room and we were able to rescue a hospital clock for another resident.”
While the original schedule estimated a year-long project, Pastore says that minor permitting delays and changes to the scope of the contract will now see Delsan-Aim finish up in October 2018.
“We’re now starting in on the Helen Lawson building, but from an overall project perspective, we’re winding down,” he says.