NSC 19
Jun 20
305 × 305 × 97 UC members, while its
interconnecting internal beams are 203 ×
203 × 46UCs. The total weight of the ring
beam, including these internal beams is 2.2t,
without the internal beams the weight is 1.7t.
Both of the mini-Gherkins have a similar
weight, but the new structure’s design
incorporates angle sections instead of SHS
members. This is said to have led to a more
economic design and one that will allow
cladding systems to be more easily fixed to
the erected structure.
The angle members that are used round
the outside of the building are all 1,050mmlong,
while the sections used for the internal
stair tower are between 1,120mm-long and
1,620mm-long.
“Also, increasing the economic design
of this structure, we slightly changed the
geometry, which enabled more repition. We
also made sure the connecting nodes were
all similar within each ring, which makes the
erection sequence easier and quicker,” says
Mr Weeden.
The steelwork for both the original
and this second Gherkin structure was
designed, modelled, detailed and fabricated
by Caunton’s apprentices in the company’s
accredited Academy, which the company says
further emphasises the educational benefits
of this enterprising scheme.
The Gherkin consists of approximately
600 steel members and is assembled into
five sections, including the base section that
has the ring beam. After this lowest section
is in place, the next four sections, which are
assembled on the ground, are subsequently
lifted into place, using a crane with a bespoke
lifting frame, which was also designed by
Caunton Engineering.
Making sure the entire structure fitted
together correctly, Caunton’s apprentices
undertook a trial erection in the company’s
car park prior to the steelwork being
delivered to the client.
Highlighting the expertise and the high
level of the apprentice’s work, the entire
structure was easily erected in less than one
day, with each section fitting exactly.
Summing up, Emeritus Professor David
Nethercot, Imperial College says: “We have
found that Constructionarium positively
influences students towards careers in
engineering and is seen as an exemplar of
best practice for other departments within
the engineering faculty.”
Education
Each section is lifted into
place by a crane using a
bespoke lifting frame
Caunton apprentices
carried out a trial
erection to ensure the
structure fitted together.
“With a ring beam replacing
holding down bolts, the Gherkin
will not just be available at the
Constructionarium’s new site,
but it can easily be moved from
site to site”
The structure consists
of five pre-assembled
sections
/Steel_section_sizes
/Steel_construction_products#Structural_hollow_sections
/Facades_and_interfaces
/Modelling_and_analysis
/Construction#Mobile_cranes
/Accuracy_of_steel_fabrication#Trial_erection
/Fabrication#Handling_and_transportation