Visualisation of the
main entrance
NSC 13
Nov/Dec 19
Photo © Aaron Courtney
were critical in optimising the number of
levels the design team could achieve within
the overall height limit. This lead to the
use of cellular beams to accommodate the
services within the structural zone, thereby
negating the need to increase the floor-toceiling
heights.
The structural zone is set at a standard
610mm height and accommodates beams
with 400mm cellular openings. The only
exception to the cellular beam design is the
area of the building that accommodates the
exit of the main ducting from the central
vertical riser.
This area had to be considered
differently due to the size of the ducts.
The ventilation ducts were consequently
accommodated beneath non-cellular
beams, which were installed within the
depth of the slab, so as not to interfere with
the important floor-to-ceiling heights.
The floorplates remain the same all the
way up the building until the upper two
levels, which have steps that provide space
for outdoor terraces.
There are two terraces, on levels six and
seven, while a plant screen extending up
from the roof of the structure provides the
appearance of a third step.
“Most columns within the walls of the
steps are situated on main steelwork lines,
and therefore do not require transfer
structures,” explains Mr Steyn.
“However, additional steelwork has
been provided to tie the columns in all
directions and some columns are situated
off main steelwork lines. This required
transfer beams, which span between
secondary beams transferring the loads
back into the main frame of the building.”
Lateral stability for the steelwork is
provided by two concrete stair and lift
cores located on the north and south
elevations. These were constructed prior to
the steelwork beginning as part of the early
concreting programme that also included
the construction of the three-storey deep
basement car park and the ground floor
slab.
Commenting on the construction
programme, Mr Cooper says: “This is a
very confined site, hemmed in on three
sides by existing buildings with only one
access route for materials, which is via the
busy Morrison Street.
“Steelwork deliveries were kept to a
minimum and the loads were erected
almost immediately. A concrete frame,
on the other hand would have required
more deliveries, which would have been
problematical.”
Once delivered, all of the steelwork was
erected via the site’s two tower cranes,
with the heaviest elements weighing 6t,
which was easily within the crane’s lifting
capacity. The 6t sections are the lowest
columns, founded on the ground floor slab.
The site was previously occupied by a
600-space automated car park that used
robots to park and retrieve vehicles,
allowing cars to be stacked in a way that
took up half the space of its competitors.
Once this structure was demolished,
one of the first tasks BAM Construction
had to undertake was the installation of a
contiguous piled wall. This provided the
lateral support for an excavation process to
deepen the existing basement and for the
installation of the core’s foundations.
“Because of the confined nature of
the site, all of the concreting works
had to be completed before we could
begin the steelwork programme for the
superstructure,” says Mr Cooper.
This prestigious development is aiming
to achieve a BREEAM ‘Excellent’ rating
and is scheduled to be complete by May
2020.
Commercial
FACT FILE
Capital Square,
Edinburgh
Main client:
BAM Properties,
Hermes Investment
Management
Architect:
Hurd Rolland
Main contractor:
BAM Construction
Structural engineer:
Blyth & Blyth
Steelwork contractor:
BHC
Steel tonnage: 1,000t
Cellular beams have
been used throughout
for service integration
Photo © Aaron Courtney
/Construction
/Design
/Concept_design#Structural_options_for_stability
/Concept_design#Concrete_or_steel_cores
/Steel_construction_products#Cellular_beams
/Fabrication#Handling_and_transportation
/Construction#Tower_cranes
/BREEAM