core. Caissons would have come with their own challenges
– long construction time, substantial traffic control plans
and, most importantly, costs – that would have made the
project economically unviable.
Structural engineers explored all the options to give their
client the best, most efficient and most economical design,
says Brian Huber, project manager for EBS Geostructural of
Breslau, Ont. EBS has specialized in micropiles and helical
piles for almost 20 years and is the Ontario distributor and
main installer of Chance helical piles, which are manufactured
in Centralia, Mo., by Chance Foundation Solutions,
now a division of Hubbell Incorporated.
The proposed tower’s location, which previously had a
one-storey commercial building and a parking garage on it,
was already owned by Old Oak Properties.
“From a cost perspective it made more sense for the
developer to demolish existing buildings on the site than
find a new vacant site elsewhere,” said Huber, who notes
that many of the logistical challenges that caisson installation
would have posed for this restricted-access downtown
site were eliminated by using helical piles; including the
need for access and egress for drill rig equipment, dump
trucks removing spoils, the ready-mix trucks delivering
concrete and the need for laydown areas for rebar cages.
“When we were first contacted, we were given a set of
preliminary loading and asked, ‘Hey, is it even remotely
possible?’” said Huber. After a thorough review process,
EBS and Chance engineers came up with a budget based on
the existing geotechnical structural loading information,
preliminary loading calculations and piling depth assumptions.
Compared to the cost of installing caissons, helical
piles would save approximately 80 per cent, and would be
substantially faster to install. This started a dialogue, Huber
said, “How can we determine if this is feasible? What are the
next steps?”
COVER FEATURE
CONTINUED ON PAGE 10
8 Q1 2020 www.pilingcanada.ca
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