The Gherkin, Lo n d o n
Norman F o s t e r
Client:
Project Manager:
Architect:
Structural Engineer:
Building Services Engineer:
Cost consultant:
Swiss Re
RWGAssociates Foster and
Partners Arup
Hilson Moran Partnership
Gardiner & Theobold
INTRODUCTION
Where is Gherkin (Swiss re Headquarters) located?
30 St Mary Axe (informally known as the Gherkin and previously as the Swiss Re Building) is a
commercial skyscraper in London's primary financial district, the City of London.
Why is it called the Gherkin?
Officially named 30 St. Mary Axe, the building has become known as its' more popular moniker,
“The Gherkin” because of its' supposed resemblance to that particular food stuff.
What is the Gherkin used for?
The majority of the building is used for offices and residences. The official name of the building is
30 St. Mary Axe, but it is commonly referred to as The Gherkin, the British word for pickled
cucumber, due to its shape.
Why is the Gherkin so famous?
Its form is so unique, that it has been given the nickname "the Gherkin." The building was designed
by famed architect Norman Foster of the Foster and Partners architectural firm
WHY IT IS CALLED MEGASTRUCTURE
A mega structure is a very large artificial object, although the
limits of precisely how large vary considerably. Some apply the
term to any especially large or tall building.
A very large, usually high-rise building or
a complex of such buildings used for many purposes, as for
apartments, offices, stores, theaters, and athletic facilities.
HISTORY
FROM BOMBING OFBALTICEXCHANGETOTHE
BUILDING OFTHEGHERKIN
 The beginning of the Gherkin's birth starts in 1992 as an
explosion rocked the financial district of London. The
Provisional IRAdetonated an explosive device near the Baltic
Exchange and catastrophically injured the building. The
building was torn down and city officials decided to put a
larger tower in its place.
 The Gherkin began as a much larger building that was dubbed
the "Millennium Tower" but which failed to materialise. The
original design of the building raised fears that it could
negatively impact air traffic from Heathrow. There were also
concerns that it may interfere with the sight-lines of St. Paul's
Dome from certain parts of the city. Once the original design
was shot down, Norman Foster created the scaled-down
version that now sits at 30 St MaryAxe.
 Construction began in 2001 and the Gherkin was finished in
December of 2003. It didn't open for the public until almost
half of a year later.
 In response to Norman Foster's Millennium Tower and 30 St
Mary Axe Proposal, the English Heritage supported newer
buildings, but perceived threat of tall buildings. SAVEBritain's
Heritage also played a heavy opposition role over
construction of any new architecture.
 With demand for space for new offices, Swiss Reclaimed
that it should be allowed to build "the Gherkin" on the
site, with economic benefit of its jobs, and a huge
investment in the UK economy back to mainlandEurope.
THEGHERKIN: HISTORYIN THECONSTRUCTION OFTHEBUILDING
First IRA bomb close to The BalticExchange
10th April 1992
Second IRA bombing. St. Mary Axe street
facade of Baltic exchange wascompletely
blown off. APRIL 1993
Foster started working on the
Millennium Tower right afterEnglish
Heritage accepted demolition of the
The Baltic Exchange.(MARCH 1996)
London Millennium Tower(400m)
planning application. August1996
Entire project of the Millennium Tower abandoned when it was decided that
Swiss Re will buy the site from Kvaerner on condition that planning permission
to knock down Baltic exchange was granted. Late 1997
Swiss Re hinted that unless it was allowed to
build Norman Foster'sdistinctive circular tower
('the Gherkin') on the site of the old Baltic
Exchange, it would take itself, its jobs and its
huge investment in the UK economy back to
mainland Europe. Early1998
ABOUT THE BUILDING

The building’s ostentatiously streamlined
form, tinted glass spirals, and visibly
operable windows call attention to its
capacity for supplementing or substituting
mechanical ventilation with natural
ventilation.

The smoothness of that crown, where the
doubly curving curtain wall resolves into a
glass dome, eliminates the roof that so
often supports chillers and fans—visible
elements of industrial environmental
control. By tucking this equipment into
plant rooms near the top of the tower—as
well as into the basement and a six-story
annex building across the plaza—the
building obscures the extent of its reliance
on energy-intensive mechanical
ventilation and temperature control.

Instead of supporting mechanical
equipment, the apex contains a private
dining room with a 360-degree view that
spectacularizes London.
Building Details and Specifications
•Height to top of dome: 179.8 m
•Height to highest occupied floor level: 167.1 m
•Number of floors above ground: 40
• Number of basement levels: single basement across whole
site
•Largest floor external diameter (lvl 17): 56.15 m
•Site area: 0.57 hectares (1.4 acres)
•Net accommodations areas:
•
Total = 64,470 m²
•
Office 46,450 m2
•
Retail 1,400 m2
•Office floor-floor: 4.15 m
•Gross superstructure floor area (incl. lightwells): 74,300 m2
•Tower Structural Steelwork
•Total weight of steel (from Arup Xsteel model): 8,358
tonnes of which:
•
29% is in the diagrid
•
24% core columns
•
47% beams
•Total number of primary steel pieces: 8 348
•Total length: 54.56 km
•Diagrid column sizes:
•
Ground – level2: 508mm f, 40mm thick
•
Level 36–38: 273mm f, 12.5mm thick
•Foundations 750mm diameter straight-shafted piles into
London Clay
•Number of piles: 333
•Total length of piles: 9 km
•Total design capacity: 117,000 Tonnes
•Design Capacity/Weight of Steel = 14tonne Load/tonne of steel
•Design Capacity/Built Area =1.814tonne load/sqm
•Load on Pile = Average 351 Tonne Load/Pile
•Hoop design tension at level 2: 7 116 kN
•Perimeter column maximum design load: 15,460 kN
• Core column maximum design load: 33,266 kN
•Occupancy = 4,000 workers
There are 792 mechanised
windows that can open in
the lightwells
STRUCTURALELEVATION
41
MATERIALS
•
•
•
•
•
35 km of steel, 10 thousand tons were used to build theSwiss
Re
24,000 square meters of glass were used for the exterior ofthe
building, equivalent to five footballfields.
The glazing to the office areas consist of a double –glazed
outer and a single –glazed inner screen.
signed to use recycled or recyclable materials
whenever possible Sandwiched in between is the
ventilated cavity which reduces heatingand cooling
requirements.
The solar-control blinds intercept solar gain before it enters
the office environment.
•
The facade is clad with double-paned glass that is
filled with argon.
•
•
•
•
The elements of the facade.
Openable glass screen.
Perforated aluminium louvers (internal sunscreen).
Acolumn casing of aluminium.
Façade frame of extruded aluminium.
Gherkin London. Windows open on the
outer skin to allow air to enter the cavity
between the inner and outer skin.
Distance between each floor:4200mm
Each closed steel frame height: 16800mm
Each glass height: 4200mm
Other than one curved , other glass are allflat.
SITE TEMPERATURE
Temperature range:
•
•
22 degrees in December
94 degrees in June
FLOORS
Ground floor and first floor consist of reception and a series
of shops at outer edge of the building with the arcade.
The design provides column-free floor space, light and views,
and incorporates many sustainable building design features.
Third tosixteenth floor is the office of swiss re insurance
company.
Spiralling light wells allow the maximum amount of sunlight
to flood the interiors.
There are private dining area at 38-40floors.
Atria between the radiating fingers of each floor link
together vertically to form a series of informal break-out
spaces. Each floor rotates 5 degrees from the one below.
The basement is used for the parking (only two wheelers ,no
four wheelers are allowed in theparking).
SITEPLAN
33RD FLOORPLAN
6TH FLOORPLAN
39tTH FLOORPLAN
21STFLOORPLAN
40TH FLOORPLAN
FRAMINGPLANS
12
BUILDING
FORM
FORM OF THE BUILDING: THEGHERKIN
 The design for 30 St Mary Axe was actually developed from ideas
that were used in the Climatroffice design by Buckminster Fuller in
the 1970s. This building was never constructed, but it was supposed
to be a free-form glass skin which allowed the building to have its
own microclimate.
 It would have been very difficult in the 1970s to design and build
such a complex structure. However, thirty years later, Foster was
able to use advanced parametric modeling to design 30 St MaryAxe
whose final design is very reminiscent of the Climatrofficedesign
SKETCHES SHOWING THE WIND
MOVEMENT AROUND THEBUILDING.
 The variation of the diameter of the plants is significant, it
measures 49 meters at the base, 56.5 at its widest, narrowingto
26.5 on the top floor, which is what gives it the appearance of
"Rocket" or "cucumber" as the Londoners have beenbaptized.
 The shape of the tower is influenced by the physical environment
of the city. The smooth flow of wind around the building was one
of the mainconsiderations.
COMPUTER SIMULATION OF
WINDFLOW FLOWS AROUND THE
BUILDING
THEGHERKIN: FORM OFTHEBUILDING
 Environmentally, its profile reduces wind deflections compared
with a rectilinear tower of similar size, helping to maintain a
comfortable environment at ground level, and creates external
pressure differentials that are exploited to drive a unique system
of natural ventilation
 The fact that the tower bulges out in the middle, reaching its
maximal diameter at the 16th floor, also helps to minimisewinds
at its slimmerbase.
STRUCTURE
“Diagrid is a series of triangle that combine gravity and
lateral support into one, making the building to be stiff,
efficient, and lighter than a traditional high rise”
VIDEO ON DIAGRID
How diagrid works?
These diagonals were affected by the width and height ratio.
The base of the building have to designed to resist moment while the top have to
resist the shear force. As a result, the foundation of a diagrid system is more
concentrate on a point to reach stability
The diagonal members in diagrid carry shear and moment. The optical angle of
the diagrid will dependent on the building height and module. The expected
optimal angle for diagonal members for diagrid structure will fall in the range of
60° to 70°.
“ a pure steel diagrid tower does not require a core for lateral resistance ”
Diagrid nodes
(1) pin node
Not rigid pin connection can be used in the symmetrical structure since the
structure have balance load.
(2) Rigid Node
the needs of rigid nodes to assist the structure to support during the construction
process.
Vertical Load
The gravity and vertical load from the building will distribute toward the apex of the
diagonal structure. Somehow, it will affected by the height and angle of the
diagonal.
The vertical forces will be divide/disperse into the other diagonal member.
Compression and tension result in the diagonal will transfer into the bottom
section.
Lateral Load
the lateral load happened toward the "flange" of the structure receiving directional
wind load. this will result the lateral load into two part; windward and leeward.
As a consequence, these diagonal members receiving two different direction of
force load. It will respond relatively. The structure able to resist both force and
achieve equilibrium.
THESERVICE
CORE
THEELEVATORS-18
PASSENGERLIFTS
THEOFFICE
AREA
THE CORE
The core takes a portion of the
vertical gravity loads and is a
secondary structure to thediagrid.
The core acts as a tie back to the
hoop structure preventing splay. The
structure system of the core is rigid
using moment frames.
 Provides rigidity
Resists torsion
 Increasesstiffness
This building has a core 9 meters wide and 36 meters long split into
five separate sections to provide additionalstrength
Core area at centre
MERITS OF DIAGRIDS:
The Diagrid structures have mostly column free exterior and interior, hence free and clear,
unique floor plans are Possible.
1)
The Glass facades and dearth of interior columns allow generous amounts of day lighting into the
structure.
2)
The use of Diagrids results in roughly 1/5th reduction in steel as compared to Braced frame
structures.
4)
The construction techniques involved are simple, yet they need to be perfect.
3)
5)
The Diagrids makes maximum exploitation of the structural Material.
6)
The diagrid Structures are aesthetically dominant and expressive.
DEMERITS OF DIAGRIDS:
1) As of yet, the Diagrid Construction techniques are not thoroughly explored.
2) Lack of availability of skilled workers . Construction crews have little or no experience
creating a DiaGrid skyscraper.
3) The DiaGrid can dominate aesthetically, which can be an issue depending upon design intent.
1) It is hard to design windows that create a regular language from floor to floor.
2) The DiaGrid is heavy-handed if not executed properly.
A CULTURAL
ICON
NATIONAL PRIDE
Back the Bid. Leap for London. Make Britain
Proud. Emblazoned across photomontages of
oversized athletes jumping over, diving off,
and shooting for architectural landmarks old
and new, these slogans appeared in 2004 on
posters encouraging Londoners to support
the city’s bid to host the 2012 Olympic
Games.
In representing Games-hosting as a leap akin
to vaulting over the Gherkin, it also
imagined public investment as the running of
a risk. By figuring the building’s dynamic
equipoise as support for the gymnast’s
virtuosity, it enlisted the Gherkin as
evidence that London possessed the
expertise and daring to handle that risk—to
manage the complex investments and
construction projects in infrastructure,
architecture, and landscape needed to host
an Olympic games.
A forty-one story cylinder that tapers inward
at its base and its top, where it peaks in a
rounded apex, the Gherkin has been
compared to many objects of similar shape,
including a pine cone, a bullet, a stubby
cigar, a pickle, and a penis.
GREEN
CONCEPTS

But a poster created three years later
offered a very different image. Created
by activists from the Camp for Climate
Action to publicize a mass protest at
Heathrow Airport against the
environmental degradation caused by
air travel, this poster shows the
Gherkin affording only precarious
footing to a giant polar bear that swats
at passing jets as its claws grasp at the
slight relief offered by spiraling
mullions and fins.

The Gherkin is an especially suitable
focus for the Camp for Climate Action
poster because the building had come
to exemplify innovation in sustainable
tall office building design.
SUSTAINABLITY : THEGHERKIN
 The tower is aerodynamically designed to reduce wind load on the structure,
whilst the lower part tapers so that wind wraps around the tower.
 The six fingers of accommodation on each floor, configured with light wells
in between, maximize daylight penetration.
 The façade design with advance glazing technologies, ventilated cavities and
blinds , provides up to 85% solarprotection.
 Gas is the main fuel used hence it will only generate half the carbon
emission.
 Overall energy serving is up to 50%.
 The façade consists of two layers of glass (the outer one double-glazed)
enclosing a ventilated cavity with computer-controlled blinds. A system of
weather sensors on the outside of the building monitors the temperature,
wind speed and level of sunlight, closing blinds and opening windowpanels
as necessary.
 The building's shape maximises the use of natural daylight, reducing the
need for artificiallighting and providing impressive long-distance views even
from deep inside the building
 On each floor, a series of interstices with 6 pipes made of natural
ventilation system, functioning as a double glazing.
 Pipes used for cooling in the summer, drawing warm air from the
building, and for heating in winter. They also allow foreasier entry
of light, with a consequent reduction in the cost of lighting.
 The systematic internal microclimate and solutions for energy
savings have led to a 50% reduction in energy consumption in any
case necessary for a building of this size.
 The ventilation system reduces conventional air conditioning use
due to the aerodynamic shape of the building, which creates air
pressure differentials in the double skin and moves air up the
building and across offices, as seen in the computer generated
ventilation models to theleft.
 Additionally, lights are on level and motion sensors, reducing
unnecessary lighting. All of this helps to reduce the building’s
heating and cooling loads and its total energy needs. Withinthe
double skin façade are blinds that can intercept solar radiation,
at a 15% solar transmission rate, and the building can then
reclaim heat from the solar radiation or reject it depending on
the cooling or heating needs of thebuilding
 The glass panels in the atriums are also tinted to reduceglare
and solar gain
Glass layers

The Gherkin is enclosed by a unique curtain wall that combines two systems.

For most of its circumference on any given office floor, the building is encased
by an exterior curtain wall of clear diamond-shaped double-glazed panels as
well as an interior curtain wall of rectangular single-glazed panels fitted with
blinds.

In this Abluft or exhaust façade, heat that builds up in the airspace between
the two curtain walls is exhausted to the outside by vents at the top of each
one- or two-story zone.

Where the enclosure adjoins the spiraling atria, the interior curtain wall is
omitted and the exterior curtain wall is tinted to reduce solar heat gain as well
as fitted with some operable windows that tilt open to admit fresh air.

When weather permits, a computerized building management system can
selectively open these windows, using the pressure differentials at atria thirty
degrees apart around the façade to draw air in and through the building.
BUILDING USE AND FUNCTIONALITY
DIVERSE OCCUPANTS
 In the past couple of years, the Gherkin has changed from a
bespoke owner-occupied London headquarters for insurance
company Swiss Re, to a prime multi-let office building, with all
but one floor occupied.
 On the downside, the building is not very spatially efficient.
The central lift, services core and six spiralling light wells
around the perimeter mean that only 63% of its gross floor
area is useful space.
CELLULAR OFFICES FOR LAWYERS
 The building is extremely popular with law firms, because the
rectangular spaces can take cellular offices Originally, the
circular floor plates were conceived of as open-plan spaces,
but this was not practical for lawyers, who need to have
confidential one-to-one discussions with clients. In addition,
the open lightwells allow sound totravel between six floors at
a time, which could compromise confidentiality.
 At a time 4000 workers can be accommodated.
 Net accommodations areas:
Office 46,450 m2
 Retail 1,400 m
 The total weight of steel used is approximately 11,000tones.
Total weight of steel : 8,358 tonnes of which:
29% is in the diagrid
24% core columns
47% beams
The designers and owners of the building also wanted to discourage
motor vehicle use by the building’s tenants. The basement of the
building provides three times the bicycle space, 118 spaces, than the
minimum required [1][13]. The building does not have car parkingfor
visitors or employees, just 5 handicap spaces and 52 motorcycle spaces
SHARED FLOORS
 The 19th floor is shared by four companies, the smallest of
which is the five-strong Primus Guaranty, which has a tiny
dealing floor and three cellular offices in one rectangular
finger.
 Sharing this floor called for an internal corridor to be wrapped
around the central core of the building to reach the lift lobby.
RESTAURANTS AND RECEPTION DOME
 Tenants make regular and enthusiastic use of the restaurants
and glass dome at the peak of the building to entertain clients.
 The 65-cover restaurant and five private dining rooms are
reserved for tenants and members of the exclusive London
Capital Club. The reception room in the dome can be hired by
outsiders.
ELEVATORS





There are 18 passenger lifts in the
building.
378 people can be vertically
transported
through the
building at speeds up to 6m per
second at any time.
In addition, there are goods and
firefighter elevators, as well as a
car park elevator to the reception
from thebasement.
Two special shuttle elevators serve
the top floors of the building.
KONEAlta™ fulfilled the architects’
requirements for customized
elevator cars and signalization.
ELEVATORSINBUILDING




3 different levels:
Low rise go from lobby to
level 12.
Medium rise liftsgo from
lobby to 22 stopping from
level 11.
High rise lifts go from lobby
to 34 stopping from level
22.
Shuttle lift goes from level
34to level 39.
ELEVATORS
IN THECORE
FIRE FIGHTING METHODS:
• Swiss Refalls within the guidance of inner London Section 20 requirements for fire
safety.
• Every sixth floor , the atria feature gardens which control and purify air movements as
well as dividing the building into firecompartments.
• The unusual light well arrangement leads to a fire escape strategy based on a variation
of phasedevacuation.
• In this case all six floors linked by a set of light wells are evacuated in the case of a fire on
any one of them.
• Where only two floors are linked then those two constitute the first phase. So the light
wells are designed following the guidance for simultaneous evacuation, which allows
them to be open tothe accommodation.
• Because the light well base floors are protected by sprinklers on the overhanging soffits
above, they can be used as office space too.
• A system of smoke curtains form smoke reservoirs in the light wells, and others delay the
transport of smoke from accommodation into the light wells.
The spiral lightwell
arrangement allows for a fire
escape strategy based on a
variation of phasedevacuation.
The building is divided into fire
safety zones at every sixth and
second floor . this allows for
the evacuation of one area ata
time as opposed to a whole
building at once.
• Natural ventilation is used for smoke clearance for the light wells and the accommodation.
• The building is sprinkle red, including arrays of window sprinklers on part of the façade of levels 2 and 3, to protect a glazed opening in the
compartment floor of level 4, directlyabove.
• However sprinklers have not been fitted in the 12m high domed space that forms the very top of the building.
• The Tower has two firefighting shafts with dedicatedlifts.
• The use of dedicated smoke detectors in each lobby which cause the vent to open in that lobby, as well as at the top of the smoke shaft and the
top of thestair.
• During a fire temperatures can be such that the window glazing may break and thus allow cool air to enter and hot gas to escape.
• Alternatively, temperatures may be such that the fire has not engulfed a large area and is not severe enough to actually break the glass.
• In both cases the temperature reached in the compartment and the duration of a fire is dependent on the amount of ventilation, and it is
assumed that sprinkler activation has not prevented the fire from growing.
FIREFIGHTING IN THEBUILDING
The smoke containment curtain is automatically lowered by a control
signal to a desired height, or the entireopening is closed, thus closing can
be programmed for two phases.
Suitable for the fire-proof fire closing of horizontal and vertical surfaces.
VERTICAL SMOKE CURTAIN BARRIERS INTHE GHERKIN
Installation of over smoke curtain barriers. Concealed
within the ceiling voids of each of the 39 floors, the Smoke
Stop™ smoke curtain barriers were developed to deploy in
the event of fire, channelling smoke away from occupant
and out of the building. This effective strategy for
containing and channelling smoke would ensurethat
Gherkin’s 41 floors were protected from filling with smoke
and provide occupants with a safe means of escape. THE
SYSTEM OF SMOKE CURTAIN FORMS THE SMOKE
RESERVOIR IN THE LIGHTWELL. NATURAL VENTILATION IS
USED FOR THE SMOKE CLEARANCE FROM THE
LIGHTWELL.
Appearance: The frame structure and the top box is normallygalvanized,
powder coated in any desired RALcolour. Can be mounted also above
suspended ceilings.
Applications: factories, warehouses, shopping centres, buildings with lobby
and atria
WORKING OF THE SMOKE CURTAINBARRIER
AIR TRAFFIC SAFETY
Air lights-There are nine aircraft warning lights that glow red
as it gets dark to alert planes overhead.
INTERESTING FACTS
1. The body of a Roman woman was
found during the Gherkin’s
construction. The body was kept in
the Museum of London and then reburied at the foot of the building,
once it was finished.
2. On 21 February 2007, IVG Immobilien AG
and UK investment firm Evans Randall
completed their joint purchase of the building
for £630 million, making it Britain’s most
expensive office building. Swiss Re booked a
gain of more than £300 million from the sale.
3. In November 2014, the Gherkin was
purchased for £700 million by the Safra
Group, controlled by the Brazilian billionaire
Joseph Safra
The Architect
Sources
http://www.archinomy.com/casestudies/669/30-st-mary-axe-the-gherkinlondon
https://prezi.com/sxt_dfdzmijt/case-studyfor-the-gherkin/
http://www.webpages.uidaho.edu/arch504u
kgreenarch/casestudies/swissre1.pdf
http://www.coopersfire.com/system/files/pri
vate/CaseStudy_The_Gherkin.pdf
http://skyscrapercenter.com/building/30-stmary-axe/2369
http://faculty.arch.tamu.edu/media/cms_pa
http://faculty.arch.tamu.edu/media/cms_page_media/4433/30StMaryAxe_1.pdf
http://brandondonnelly.com/post/67910871416/who-knew-gherkins-were-so-aerodynamic
http://www.greendesignetc.net/Buildings_09/Building_Shen_Yuming_paper.pdf
http://www.engagingplaces.org.uk/teaching%20resources/art63639
http://www.engagingplaces.org.uk/teaching%20resources/art63639
http://www.archinomy.com/case-studies/669/30-st-mary-axe-the-gherkin-london
http://www.building.co.uk/30-st-mary-axe-a-gherkin-to-suit-all-tastes/3111783.article
http://www.sustainablebuild.co.uk/sustainable-building-around-world.html
http://www.skyscrapernews.com/swiss.htm
http://www.fosterandpartners.com/projects/30-st-mary-axe/gallery/
http://www.slideshare.net/adadarmon/swiss-re-building-london