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| BANKER'S HALL CALGARY |
DEVELOPER: TRIZEC CORPORATION LTD.
ARCHITECT: THE COHOS EVAMY PARTNERSHIP |
The first tower of the Bankers Hall
project was topped off on June 26, 1989. The post modern
architectural expression of the project employs an optimized
reinforced concrete frame with a clear span of 12 metres from
the perimeter columns to the central core.
In addition to the special concrete
mixes, designed to achieve 120 days design strengths for the
columns and core walls, the structure also incorporated several
unique features such as the largest foundation raft in Canada,
placed in one monolithic casting. The foundation rafts (two) are
located under each of the towers and were designed to compensate
for the uncertain soil conditions of the site. The rafts were
2.7 metres thick containing approximately 10,000 cubic metres of
concrete and 1,800 tons of reinforcing steel each.
The concrete for the raft was
specially designed incorporating superplatizers, as well as other
constituents, to minimize the heat of hydration. The substructure
incorporating parking levels and loading dock areas was specified
with epoxy coated reinforcing steel and many of the criteria set out
in CSA/CAN - S413-87, Parking Structures.
The superstructures of the towers were
designed to resist wind forces by employing the tube in tube
system, consisting of the central core and rigid frames located at the
perimeter of the floor plates. The lateral sway of the structure was
minimized to assure the comfort of its occupants.
The superstructure also employs some unique
systems such as the two storey deep transfer beams which were monolithically
cast at the north and south ends of the east tower, between levels five and eight.
The ground floor incorporates a series of four continous
bonded, post-tensioned, beams spanning twenty-six metres, and carrying the
six storey podium structure above. The above beams were
post-tensioned in three stages in accordance with the progress of construction.
When completed the project will be a notable landmark
in downtown Calgary, providing a total of 3 million square feet of rentable space.
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