away from the existing foundations. In some cases, larger
diameter holes needed to be drilled in order to get closer
to the buildings and get the piles in their design locations.
Occasionally, pile sizes had to be redesigned to suit the onsite
conditions and true locations of the footings. deep’s use of
conventional drilling equipment and methods gave the flexibility
required to change tooling sizes on the fly and keep the
job productive.
A cutting advantage: Knowing the ground you’re in
With 45 years of experience in the Toronto and Southern
Ontario region, deep is extremely familiar with the soil conditions
in the area and has a very well documented record
of data for each block of real estate. This gave the team at
deep a precise advantage: the foresight required to decide
what equipment would be most effective for the needs of the
project.
The Massey project sites consisted of mostly stiff to hard
native silty clay till overlying shale bedrock interspersed with
occasional limestone layers. The soil conditions were conducive
to open hole drilling. Having the ability to drill holes open
was favourable, as it allowed deep to drill without a casing,
which meant holes could be drilled closer to the buildings.
Even more, it was faster to change tooling for different hole
PROJECT SPOTLIGHT
diameters, and less materials were required on the job, which
reduced congestion of an already tight jobsite.
Location challenges for the Massey Hall and
Tower projects
In Toronto, high population density, busy city streets, local
and international events, existing infrastructure, historic
buildings and numerous ongoing construction projects combine,
creating an abundance of challenging conditions that
define Toronto’s construction industry. The coordination of
the shoring, excavation and caisson foundation work for the
Massey Hall and Tower projects had all of these constraints
and a few more unique obstacles to contend with.
Even with the complicated site
configurations and challenging
drill sequences, deep’s
drilling and piling operations
sustained no damage to any
of the historical structures
surrounding the sites.
Constraints and obstacles
1. The busy pedestrian and vehicular traffic on Yonge Street
limited all construction access to be off of Victoria Street
on the east end of the site. With streetcars passing by
regularly and St. Michael’s Hospital across the road, there
was no option for staging of trucks on Victoria Street. All
deliveries had to be timely and had to be received into the
jobsite immediately.
2. The demolition of the Prince Albert Building behind
Massey Hall was being undertaken concurrently with the
beginning of the foundation work. As a result, the only
site access off Victoria Street was limited to a 12-foot wide
laneway, which made concrete and steel deliveries and
movement of large drilling equipment difficult.
3. Massey Hall’s existing foundations were sensitive, which
limited any heavy equipment from being positioned anywhere
within a 23-foot exclusion zone from the exposed
walls. However, some piles had to be drilled within inches
of Massey’s exterior wall. deep used an LS218 crawler
crane with a Calweld drill attachment in order to reach
out far enough to drill these piles while equipment maintained
position outside of the exclusion zone.
4. The east half of the old CIBC building was also demolished
before the foundation works. This left a large excavation
in the southwest end of the site, which reduced the area
of the drill’s work platform and required careful planning
and safe execution of the movements of the heavy
equipment.
5. Previously demolished buildings left the site with layers
of rubble and debris 20 feet deep that had to be drilled
through during installation of the shoring piles. (But the
Klemm 807-7 tieback drill installing tiebacks
before temporary bridge installation
PILING CANADA 51