Mixed-use
Cellular beams have
been used for all new
floors
NSC 19
June 19
emission free operation for 26 years.”
Employing the same design consultant
from the original scheme, the project will see
the five-storey building extended upwards
with the addition of three new steel-framed
office floors and a roof plant level.
Meanwhile, an unusually large 36m-wide
atrium will be partially infilled with one
new bay of steelwork all the way around,
creating more office space for each of the
existing floors and a smaller but impressive
18m-wide atrium space.
Steelwork for the new upper floors is
based around a 9m column grid pattern, in
line with the existing structure’s layout. For
the new infill floor areas inside the atrium,
a series of long beams create an open-plan
floor area.
These new floor beams are all
approximately 18m long, but vary in length
due to the atrium stepping in and out at
every floor with balconies and breakout
spaces.
The atrium starts at level one, as this was
originally designed as a large trading floor
and extends across the building’s entire
footprint and also has a slightly higher floorto
ceiling height.
The new nine-storey building is now
centred around this reconfigured atrium,
which will provide links between floors via
internal feature staircases.
Explaining the decision to use a steelframed
solution for the project’s new
additions, Mr Robertson says: “A key
part of our design strategy was to employ
lightweight steel-framed construction for
the new floors and atrium infill framing,
alongside limiting the proposed imposed
loading requirements for the office floors
and roof plant. This, alongside a range of
innovative strengthening techniques for
the existing structure, resulted in almost
doubling the internal area of the building.”
Unusually for a concrete-framed structure,
1 Triton Square’s original design contained
four braced steel cores, one in each corner.
Steel cores were primarily chosen because
they were suited to the awkward geometry
in these areas, with various riser, lift and
stair openings to be accommodated. They
were also simpler to coordinate with the
pre-fabricated risers originally employed on
the scheme. 20
New steelwork
partially infills some of
the atrium, creating a
smaller void
A core in the south east
corner, which is split in
two, has been infilled
with new steelwork
/Braced_frames
/Steel-supported_glazed_facades_and_roofs#Atrium_Roofs_and_Sky_lights
/Concept_design#Floor_grids
/Residential_and_mixed-use_buildings#Balcony_systems
/The_case_for_steel#Take_a_load_off_your_foundations
/Concept_design#Concrete_or_steel_cores