The Gherkin, Lo n d o n Norman F o s t e r Presented By : Client: Project Manager: Architect: Structural Engineer: Building Services Engineer: Cost consultant: Swiss Re RWGAssociates Foster and Partners Arup Hilson Moran Partnership Gardiner & Theobold Yogesh Jatav 151110239 Viriezo Vizo 151110221 Adarsh kumar 151110236 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