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Shell structure

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Shell structure

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Shell structure

  1. 1. SHELL STRUCTURE BY ARCHIMAN BISWAS PUJA AGARWAL PURBITA SAMANTA SAYANTAN DAS SUSMITA PAUL
  2. 2. Shell: Shell structures are also called plate structures. They are lightweight constructions using shell elements. These elements, typically curved, are assembled to make large structures. Typical applications include aircraft fuselages, boat hulls, and the roofs of large buildings. A thin shell is defined as a shell with a thickness which is small compared to its other dimensions and in which deformations are not large compared to thickness. A primary difference between a shell structure and a plate structure is that, in the unstressed state, the shell structure has curvature as opposed to the plates structure which is flat. Membrane action in a shell is primarily caused by in-plane forces (plane stress), but there may be secondary forces resulting from flexural deformations. Where a flat plate acts similar to a beam with bending and shear stresses, shells are analogous to a cable which resists loads through tensile stresses. The ideal thin shell must be capable of developing both tension and compression.
  3. 3. NATURAL SHELLS THE TERM “SHELL” IS USED TO DESCRIBE THE STRUCTURES WHICH POSSESS STRENGHT AND RIGIDITY DUE TO ITS THIN, NATURAL AND CURVED FORM SUCH AS SHELL OF EGG, A NUT, HUMAN SKULL, AND SHELL OF TORTISE.
  4. 4. Shell: The most popular types of thin-shell structures are:  Concrete shell structures, often cast as a monolithic dome or stressed ribbon bridge or saddle roof. The thin concrete shell structures are a lightweight construction composed of a relatively thin shell made of reinforced concrete, usually without the use of internal supports giving an open unobstructed interior. The shells are most commonly domes and flat plates, but may also take the form of ellipsoids or cylindrical sections, or some combination thereof. Most concrete shell structures are commercial and sports buildings or storage facilities. There are two important factors in the development of the thin concrete shell structures: The first factor is the shape which was was developed along the history of these constructions. Some shapes were resistant and can be erected easily. However, the designer’s incessant desire for more ambitious structures did not stop and new shapes were designed. The second factor to be considered in the thin concrete shell structures is the thickness, which is usually less than 10 centimeters. For example, the thickness of the Hayden planetarium was 7.6 centimeters.
  5. 5. Shell: Advantages of Concrete Shells:  The curved shapes often used for concrete shells are naturally strong structures.  Shell allowing wide areas to be spanned without the use of internal supports, giving an open, unobstructed interior.  The use of concrete as a building material reduces both materials cost and the construction cost.  As concrete is relatively inexpensive and easily cast into compound curves. Disadvantages of Concrete Shells  Since concrete is porous material, concrete domes often have issues with sealing. If not treated, rainwater can seep through the roof and leak into the interior of the building. On the other hand, the seamless construction of concrete domes prevents air from escaping, and can lead to buildup of condensation on the inside of the shell. Shingling or sealants are common solutions to the problem of exterior moisture, and ventilation can address condensation.
  6. 6. Shell: Advantages of Concrete Shells:  The curved shapes often used for concrete shells are naturally strong structures.  Shell allowing wide areas to be spanned without the use of internal supports, giving an open, unobstructed interior.  The use of concrete as a building material reduces both materials cost and the construction cost.  As concrete is relatively inexpensive and easily cast into compound curves. Disadvantages of Concrete Shells  Since concrete is porous material, concrete domes often have issues with sealing. If not treated, rainwater can seep through the roof and leak into the interior of the building. On the other hand, the seamless construction of concrete domes prevents air from escaping, and can lead to buildup of condensation on the inside of the shell. Shingling or sealants are common solutions to the problem of exterior moisture, and ventilation can address condensation.
  7. 7. Shell:  Lattice shell structures, also called grid shell structures, often in the form of a geodesic dome or a hyperboloid structures.  Membrane structures, which include fabric structures and other tensile structures, cable domes, and pneumatic structures. NATURAL SHELLS INTERSECTING SHELLS CHAPEL LOMAS DE CUERNAVACA PIER LUIGI NERVI PALAZZETTO DELLO SPORT BRITISH MUSEUM, LONDON BY NORMAN FOSTER LOTUS TEMPLE, INDIA  SYDNEY OPERA HOUSE AND MANY…
  8. 8. SINGLE OR DOUBLE CURVATURE SHELLS • SINGLE CURVATURE SHELL: ARE CURVED ON ONE LINEAR AXIS AND ARE A PART OF A CYLINDER OR CONE IN THE FORM OF BARREL VAULTS AND CONOID SHELLS. • DOUBLE CURVATURE SHELL: ARE EITHER PART OF A SPHERE, OR A HYPERBOLOID OF REVOLUTION. • THE TERMS SINGLE CURVATURE AND DOUBLE CURVATURE DO NOT PROVIDE A PRECISE GEMOETRIC DISTINCTION BETWEEN THE FORM OF SHELL BECAUSE A BARREL VAULT IS SINGLE CURVATURE BUT SO IS A DOME. • THE TERMS SINGLE AND DOULBE CURVATURE ARE USED TO DISTINGUISH THE COMPARITIVE RIGIDITY OF THE TWO FORMS AND COMPLEXITY OF CENTRING NECESSARY TO CONSTRUCT THE SHELL FORM. BARREL VAULT CONOID DOME HYPERBOLOID PARABOLOID
  9. 9. FORMS OF CURVATURE: SURFACES OF REVOLUTION: SURFACES OF REVOLUTION ARE GENERATED BY THE REVOLUTION OF A PLANE CURVE, CALLED THE MERIDIONAL CURVE, ABOUT AN AXIS, CALLED THE AXIS OF REVOLUTION. IN THE SPECIAL CASE OF CYLINDRICAL AND CONICAL SURFACES, THE MERIDIONAL CURVE CONSISTS OF A LINE SEGMENT. E.G. : CYLINDERS, CONES, SPHERICAL OR ELLIPTICAL DOMES, HYPERBOLOIDS OF REVOLUTION, TOROIDS.
  10. 10. FORMS OF CURVATURE: RULED SURFACES : RULED SURFACES ARE GENERATED BY SLIDING EACH END OF A STRAIGHT LINE ON THEIR OWN GENERATING CURVE. THESE LINES ARE NOT NECESSARILY AT RIGHT ANGLE TO THE PLANES CONTAINING THE END CURVES. COOLING TOWER, GENERATED BY STRAIGHT LINES GOULD 1988 CONOID, GENERATED BY STRAIGHT LINE TRAVELING ALONG ANOTHER STRAIGHT LINE AT ONE END AND CURVED LINE AT OTHER END. JOEDICKE 1963
  11. 11. DEVELOPABLE SURFACES (SINGLY CURVED) : DEVELOPABLE SURFACE IS A SURFACE THAT CAN BE UNROLLED ONTO A FLAT PLANE WITHOUT TEARING OR STRETCHING IT. IT IS FORMED BY BENDING A FLAT PLANE, THE MOST TYPICAL SHAPE OF A DEVELOPABLE SHELL IS A BARREL, AND A BARREL SHELL IS CURVED ONLY IN ONE DIRECTION. BARREL : ARCH ACTION & BEAM ACTION TOGETHER MAKE A BARREL. THERE ARE MAINLY TWO TYPES OF BARREL : - LONG BARRELS , ARCH ACTION IS PROMINENT - SHORT BARRELS, BEAM ACTION IS PROMINENT STRUCTURAL BEHAVIOR OF SHORT BARREL SHELLS: THESE SHELLS ARE TYPICALLY SUPPORTED AT THE CORNERS AND CAN BEHAVE IN ONE OR A COMBINATION OF THE FOLLOWING WAYS: STRUCTURAL BEHAVIOR OF LONG BARREL SHELLS: THESE ARE TYPICALLY SUPPORTED AT THE CORNERS AND BEHAVE STRUCTURALLY AS A LARGE BEAM.
  12. 12. CENTERING OF SHELLS CENTERING IS THE TERM USED TO DESCRIBE THE NECESSARY TEMPORARY SUPPORT ON WHICH THE CURVED R.C.C SHELL STRUCTURE IS CAST. THE CENTERING OF A BARREL VAULT, WHICH IS PART OF A CYLINDER WITH SAME CURVATURE ALONG ITS LENGTH; IS LESS COMPLEX. THE CENTERING OF CONOID, DOME AND HYPERBOLOID OF REVOLUTION IS MORE COMPLEX DUE TO ADDITIONAL LABOUR AND WASTEFUL CUTTING OF MATERIALS TO FORM SUPPORT FOR SHAPES THAT ARE NOT OF UNIFORM LINEAR CURVATURE. THE ATTRACTION OF SHELL STRUCTURES LIES IN THE ELEGANT SIMPLICITY OF CURVED SHELL FORMS THAT UTILISE THE NATURAL ATRENGTH AND STIFFNESS OF SHELL FORMS WITH GREAT ECONOMY IN THE USE OF MATERIALS. THE DISADVANTAGE OF SHELL STRUCTURE IS THEIR COST. THE SHELL STRUCTURE IS MORE EXPENSIVE DUE TO CONSIDERABLE LABOUR REQUIRED TO CONSTRUCT THE CENTERING ON WHICH THE SHELL IS CAST.
  13. 13. CONSTRUCTION OF R.C.C BARREL VAULT THE BARREL VAULT IS THE MOST STRAIGHT FORWARD SINGLE CURVATURE SHELL CONSTRUCTION. IT IS THE PART OF A CYLINDER OR BARREL WITH SAME CURVATUREALONG ITS LENGTH. ANY NUMBER OF CONTINUOUS BARRELS OR CONTINUOUS SPANS ARE POSSIBLE EXCEPT THAT EVENTUALLY PROVISION IS MADE FOR THE EXPANSION OF THE JOINTS IN A LARGE STRUCTURES. THE BARREL VAULTS ARE USED AS PARKING, MARKET PLACE, ASSEMBLY HALL ,ETC. TYPES OF BARREL VAULTS 1. SHORT SPAN BARREL VAULTS 2. LONG SPAN BARREL VAULTS
  14. 14. EVOLUTION
  15. 15. CONSTRUCTION OF R.C.C BARREL VAULT WIDTH OF THE VAULT AS A MULTIBAY . SHORT SPAN BARREL VAULT SHORT SPAN BARREL VAULTS ARE THOSE IN WHICH SPAN IS SHORTER THAN ITS WIDTH. IT IS USED FOR THE WIDTH OF THE ARCH RIBS BETWEEN WHICH THE BARREL VAULT SPAN. LONG SPAN BARREL VAULT LONG SPAN BARREL VAULTS ARE THOSE IN WHICH SPAN IS LARGER THAN ITS WIDTH. STRENGTH OF THE STRUCTURE LIES AT THE RIGHT ANGLES TO THE CURVATURE TO THAT SPAN IS LONGITUDINAL TO THE CURVATURE. USUAL SPAN OF THE LONGITUDINAL BARREL VAULT IS FROM 12-30 M WITH ITS WIDTH BEING ABOUT 1/2 THE SPAN AND RISE IS 1/5 OF THE WIDTH. TO COVER LARGER AREAS MULTIBAY ,MULTI SPAN ROOFS CAN BE USED WHERE THE ROOF IS EXTENDED ACROSS THE
  16. 16. CONSTRUCTION OF R.C.C BARREL VAULT: WEATHER. STIFFENING BEAMS AND ARCHES: UNDER LOCAL LOADS THE THIN SHELL OF THE BARREL VAULT WILL TEND TO DISTORT AND LOSE SHAPE AND EVEN COLLAPSE IF THE RESULTANT STRESSES WERE MORE. TO STRENGTHEN THE SHELL AGAINST THIS POSSIBILITY, STIFFENING BEAMS OR ARCHES ARE CAST INTEGRALLY WITH THE SHELL. THE COMMON PRACTICE IS TO PROVIDE A STIFFENING MEMBER BETWEEN THE COLUMN SUPPORTING THE SHELL. DOWNSTAND STIFFENING RCC BEAM IS MOST EFFICIENT BECAUSE OF ITS DEPTH, BUT THIS INTERRUPTS THE LINE OF SOFFIT OF VAULTS, FOR THIS UPSTAND STIFFENING BEAM IS USED. THE DISADVANTAGE OF UPSTAND BEAM IS THAT IT BREAKS UP THE LINE OF ROOF AND NEED PROTECTIONS AGAINST
  17. 17. CONSTRUCTION OF R.C.C BARREL VAULT: EDGE AND VALLEY BEAMS: DUE TO SELF WEIGHT AND IMPOSED LOAD THE THIN SHELL WILL TEND TO SPREAD AND ITS CURVATURE FLATTEN OUT. TO RESIST THIS RCC EDGE BEAMS ARE CAST BETWEEN COLUMNS. EDGE BEAMS MAY BE CAST AS DROPPED BEAMS OR UPSTAND BEAMS OR PARTIALLY AS BOTH. IN HOT CLIMATE THE DROPPED BEAM IS USED WHEREAS IN TEMPERATE CLIMATE UPSTAND BEAM IS USED TO FORM DRAINAGE CHANNEL FOR RAIN WATER. IN MULTI-BAY STRUCTURES, SPREADING OF THE VAULTS IS LARGELY TRANSMITTED TO THE ADJACENT SHELLS, SO DOWN STAND AND FEATHER VALLEY BEAM IS USED.
  18. 18. CONSTRUCTION OF R.C.C BARREL VAULT: EXPANSION JOINTS: THE CHANGE IN TEMPERATURE CAUSES THE EXPANSION AND CONTRACTION IN CONCRETE STRUCTURES, WHICH CAUSES THE STRUCTURES TO DEFORM OR COLLAPSE. TO LIMIT THIS CONTINUOUS EXPANSION JOINTS ARE FORMED AT THE INTERVAL OF ABOUT 30M, ALONG THE SPAN AND ACROSS THE WIDTH OF THE MULTI-BAY AND MULTI-SPAN BARREL VAULT ROOFS. LONGITUDINAL EXPANSION JOINTS ARE FORMED IN A UP STAND VALLEY.
  19. 19. CONSTRUCTION OF R.C.C BARREL VAULT: ROOF LIGHTS: TOP LIGHT CAN BE PROVIDED BY DECK LIGHT FORMED IN THE CROWN OF VAULT OR BY DOME LIGHT. THE DECK LIGHT CAN BE CONTINUOUS OR FORMED AS INDIVIDUAL LIGHTS.ROOF LIGHTS ARE FIXED TO AN UPSTAND CURB CAST INTEGRALLY WITH THE SHELL. ADVANTAGE OF THE SHELL IS THAT ITS CONCAVE SOFFIT REFELECTS AND HELPS TO DISPERSE LIGHT OVER AREA BELOW. DISADVANTAGE IS THAT TOP LIGHT MAY CAUSE OVER HEATING AND GLARE. ROOF COVERING: SHELLS MAY BE COVERED WITH NON-FERROUS SHEET METAL, ASPHALT, BITUMEN FELT, A PLASTIC MEMBRANE OR A LIQUID RUBBER BASE COATING. ROOF INSULATION: THE THIN SHELL OFFERS POOR RESISTANCE TO TRANSFER OF HEAT. THE NEED TO ADD SOME FORM OF INSULATING LINING ADDS CONSIDERABLY TO COST OF SHELL. THE MOST SATISFACTORY METHOD OF INSULATION IS TO SPREAD A LIGHT WEIGHT SCREED OVER THE SHELL. DIFFICULTIES OF PROVIDING INSULATION AND MAINTING THE ELEGANCE OF CURVED SHAPE MAKES THESE STRUCTURES LARGELY UNSUITED TO HEATED BUILDINGS IN TEMPERATE CLIMATE.
  20. 20. CONSTRUCTION OF R.C.C BARREL VAULT:
  21. 21. (DOUBLY CURVED) : E.G., SPHERE OR HYPERBOLIC PARABOLOID. THEY ARE MAINLY CLASSIFIED AS : 1) SYNCLASTIC 2) ANTICLASTIC SYNCLASTIC SHELLS: THESE SHELLS ARE DOUBLY CURVED AND HAVE A SIMILAR CURVATURE IN EACH DIRECTION. E.G. DOMES A DOME IS A GOOD EXAMPLE OF A SYNCLASTIC SHELL, IT IS DOUBLY CURVED AND CAN BE FORMED BY ROTATING A CURVED LINE AROUND AN AXIS. A DOME CAN BE SPLIT UP INTO TWO DIFFERENT DIRECTIONS; VERTICAL SECTIONS SEPARATED BY LONGITUDINAL ARCH LINES (ALSO CALLED MERIDIANS), AND HORIZONTAL SECTIONS SEPARATED BY HOOPS OR PARALLELS. STRUCTURAL BEHAVIOR : SIMILAR TO ARCHES UNDER A UNIFORM LOADING THE DOME IS UNDER COMPRESSION EVERYWHERE, AND THE STRESSES ACT ALONG THE ARCH AND HOOP LINES. FORMS OF CURVATURE:
  22. 22. CONOIDS: FORMED BY MOVING A ONE END OF A STRAIGHT LINE ALONG A CURVED PATH AND THE OTHER ALONG A STRAIGHT PATH. HYPERBOLOIDS: FORMED BY ROTATING A STRAIGHT LINE AROUND A VERTICAL AXIS. ANTICLASTIC SHELLS : ARE DOUBLY CURVED BUT EACH OF THE TWO CURVES HAVE THE OPPOSITE DIRECTION TO THE OTHER. E.G. SADDLE POINTS. ANTICLASTIC CONOIDS, HYPERBOLIC PARABOLOID AND HYPERBOLOIDS ARE ALL CONSIDERED TO THE ANTICLASTIC SHELL BECAUSE THEY ARE SADDLED SHAPE WITH DIFFERENT CURVATURE IN EACH DIRECTION AND STRAIGHT LINES CAN BE DRAWN OF THE SURFACE. FORMS OF CURVATURE: (DOUBLY CURVED) : CONOID HYPERBOLOID PARABOLOID
  23. 23. HYPERBOLIC PARABOLOID: FORMED BY SWEEPING A CONVEX PARABOLA ALONG A CONCAVE PARABOLA OR BY SWEEPING A STRAIGHT LINE OVER A STRAIGHT PATH AT ONE END AND ANOTHER STRAIGHT PATH NOT PARALLEL TO THE FIRST. STRUCTURAL BEHAVIORS: DEPENDING ON THE SHAPE OF THE SHELL RELATIVE TO THE CURVATURE, THERE WILL BE DIFFERENT STRESSES. SHELL ROOFS, HAVE COMPRESSION STRESSES FOLLOWING THE CONVEX CURVATURE AND THE TENSION STRESSES FOLLOW THE CONCAVE CURVATURE. FORMS OF CURVATURE: (DOUBLY CURVED) :
  24. 24. CHAPEL LOMAS DE CUERNAVACA
  25. 25. THIS HYPERBOLOID STRUCTURE IS THE KOBE TOWER IN JAPAN.
  26. 26. VLADMIR SHUKHOV TOWER (1922)
  27. 27. FORMS OF CURVATURE: FIG. (A) REPRESENTS A DOUBLY CURVED SHELL WITH NO AXIS OF SYMMETRY, SHOWS A SPHERICAL DOME SUPPORTED ON A WALL. WHENEVER THE SHELLS ARE SUPPORTED VERTICALLY AT THEIR EDGES, A TENSION TIE IS REQUIRED AROUND THE PERIMETER AT THE INTERSECTION OF THE DOME AND THE WALL. HOWEVER, IT IS IMPORTANT TO NOTE THAT THE TIE WILL BE FUNICULAR FOR ANY SHAPE OF EITHER THE PLAN OR ELEVATION. FIG. (B) THE SHELL HAS POSITIVE CURVATURE AND CONTINUOUS VERTICAL SUPPORT. TENSION TIE :
  28. 28. FORMS OF CURVATURE: THE SUPPORT MAY BE A CONTINUOUS WALL OR STIFF BEAMS BETWEEN ADEQUATELY SPACED COLUMNS. IT IS INTERESTING THAT THE STRAIGHT PARTS OF THE TIE IN FIG. (C) DO NOT REQUIRE TIES ACROSS THE BUILDING. THE THRUSTS ARE TAKEN BY SHEAR FORCES THROUGH THE WIDTH OF THE SHELL, AND ONLY TENSION FORCES EXIST IN THE TIE. CYLINDRICAL SHELL COMBINED WITH SPHERICAL SHELL TENSION TIE :
  29. 29. TYPES OF SHELL STRUCTURES: THE DISTINGUISHING FEATURE OF THE FOLDED PLATE IS THE EASE IN FORMING PLANE SURFACES. A FOLDED PLATE MAY BE FORMED FOR ABOUT THE SAME COST AS A HORIZONTAL SLAB AND HAS MUCH LESS STEEL AND CONCRETE FOR THE SAME SPANS. THE PRINCIPLE COMPONENTS IN A FOLDED PLATE STRUCTURE CONSIST OF : 1) THE INCLINED PLATES 2) EDGE PLATES WHICH MUST BE USED TO STIFFEN THE WIDE PLATES 3) STIFFENERS TO CARRY THE LOADS TO THE SUPPORTS AND TO HOLD THE PLATES IN LINE 4) COLUMNS TO SUPPORT THE STRUCTURE IN THE AIR. FOLDED PLATE SHELLS: FOLDED PLATE TRUSS TAPERED FOLDED PLATES CANOPIES Z SHELL THREE SEGMENT FOLDED PLATE
  30. 30. Folded Plates system
  31. 31. Folded-Plate Hut in Osaka
  32. 32. Folded Plates Library
  33. 33. TYPES OF SHELL STRUCTURES: BARREL VAULTS ARE PERHAPS THE MOST USEFUL OF THE SHELL STRUCTURES BECAUSE THEY CAN SPAN UPT O 150 FEET WITH A MINIMUM OF MATERIAL. THEY ARE VERY EFFICIENT STRUCTURES BECAUSE THE USE THE ARCH FORM TO REDUCE STRESSES AND THICKNESSES IN THE TRANSVERSE DIRECTION. CYLINDRICAL BARREL VAULTS: MULTIPLE BARRELS - OUTSIDE STIFFENERSUNSTIFFENED EDGESCORRUGATED CURVES THE LAZY S
  34. 34. TYPES OF SHELL STRUCTURES: A DOME IS A SPACE STRUCTURE COVERING A MORE OR LESS SQUARE OR CIRCULAR AREA. THE BEST KNOWN EXAMPLE IS THE DOME OF REVOLUTION, AND IT IS ONE OF THE EARLIEST OF THE SHELL STRUCTURES. EXCELLENT EXAMPLES ARE STILL IN EXISTENCE THAT WERE BUILT IN ROMAN TIMES. THEY ARE FORMED BY A SURFACE GENERATED BY A CURVE OF ANY FORM REVOLVING ABOUT A VERTICAL LINE. THIS SURFACE HAS DOUBLE CURVATURE AND THE RESULTING STRUCTURE IS MUCH STIFFER AND STRONGER THAN A SINGLE CURVED SURFACE, SUCH AS A CYLINDRICAL SHELL. DOMES OF REVOLUTION: SPHERE SEGMENT HALF SPHERE DOMES - SQUARE IN PLAN
  35. 35. PIER LUIGI NERVI PALAZZETTO DELLO SPORT
  36. 36. A GEODESIC DOME DESIGNED BY BUCKMINSTER FULLER (A NEO FUTURISTIC ARCHITECT)
  37. 37. MOST SUITABLE MATERIAL THE MATERIAL MOST SUITED FOR CONSTRUCTION OF SHELL STRUCTURE IS CONCRETE BECAUSE IT IS A HIGHLY PLASTIC MATERIAL WHEN FIRST MIXED WITH WATER THAT CAN TAKE UP ANY SHAPE ON CENTERING OR INSIDE FORMWORK. SMALL SECTIONS OF REINFORCING BARS CAN READILY BE BENT TO FOLLOW THE CURVATURE OF SHELLS. ONCE THE CEMENT HAS SET AND THE CONCERETE HAS HARDENED THE R.C.C MEMBRANE OR SLAB ACTS AS A STRONG, RIGID SHELL WHICH SERVES AS BOTH STRUCTURE AND COVERING TO THE BUILDING.
  38. 38. BRITISH MUSEUM , LONDON • Designed by Foster and Partners, the Queen Elizabeth II Great Court transformed the Museum’s inner courtyard into the largest covered public square in Europe. It is a two- acre space enclosed by a spectacular glass roof with the world-famous Reading Room at its centre. • The court has a tessellated glass roof designed by Buro Happold and executed by Waagner-Biro, covering the entire court and surrounds the original circular British Museum Reading Room in the centre, now a museum. • It is the largest covered square in Europe. • Since the circular structure is not set precisely in the middle of the courtyard, the glass roof has a complex geometric form. • The double-curved steel framework was delivered in segments and welded together on site. • To avoid applying any sideways load to the quadrangle buildings, the roof is supported on sliding bearings. These allow the structure to move naturally. • The glass and steel roof is made up of 4,878 unique steel members connected at 1,566 unique nodes and 1,656 pairs of glass windowpanes making up 6,100m2 of glazing; each of a unique shape because of the undulating nature of the roof. • A slightly unearthly quality of light comes from the mass of green ceramic dots covering the outer panes of glass to limit the amount of sunlight entering the court.
  39. 39. SYDNEY OPERA HOUSE:
  40. 40. SYDNEY OPERA HOUSE: SYSTEM SPANS AND EFFECTIVE SPANS: THE SYDNEY OPERA HOUSE SPANS UP TO 164 FEET. THE ARCHES ARE SUPPORTED BY OVER 350KM OF TENSIONED STEEL CABLE. THE SHELL THICKNESS GOES FROM 3 TO 4 INCHES. ALL SHELLS WEIGHT A TOTAL OF 15 TONS. THIS INVOLVED LAYING THE FOUNDATIONS AND BUILDING A PODIUM 82 FEET (25 M) ABOVE SEA LEVEL. MORE THAN 39,239 CUBIC FEET (30,000 M3) OF ROCK AND SOIL WERE REMOVED BY EXCAVATORS. THE FOUNDATION WAS BUILT ATOP A LARGE ROCK THAT SAT IN SYDNEY HARBOUR. THE SECOND STAGE SAW THE BUILDING OF THE SHELLS, THE PODIUM STRUCTURE, THE STAGE TOWER, AND THE NECESSARY MACHINERY. CABLE BEAMS WERE BUILT AND REINFORCED BY STEEL CABLES TO RELEASE THE STRESS OF THE WEIGHT. THE STRENGTH OF THE CABLES WAS TESTED BY LOADING ADDITIONAL WEIGHTS. WHEN THE BUILDERS WERE SATISFIED THAT THE CABLES WOULD SUPPORT, THE BEAMS WERE MADE EXTENDABLE BY OTHER BEAMS.
  41. 41. SYDNEY OPERA HOUSE: SYSTEM SPANS AND EFFECTIVE SPANS: THE "SHELLS" WERE PERCEIVED AS A SERIES OFPARABOLAS SUPPORTED BY PRECAST CONCRETE RIBS. THE FORMWORK FOR USING IN-SITU CONCRETE WOULD HAVE BEEN PROHIBITIVELY EXPENSIVE, BUT, BECAUSE THERE WAS NO REPETITION IN ANY OF THE ROOF FORMS, THE CONSTRUCTION OF PRE-CAST CONCRETE FOR EACH INDIVIDUAL SECTION WOULD POSSIBLY HAVE BEEN EVEN MORE EXPENSIVE. THE DESIGN TEAM WENT THROUGH AT LEAST 12 ITERATIONS OF THE FORM OF THE SHELLS TRYING TO FIND AN ECONOMICALLY ACCEPTABLE FORM (INCLUDING SCHEMES WITH PARABOLAS, CIRCULAR RIBS AND ELLIPSOIDS) BEFORE A WORKABLE SOLUTION WAS COMPLETED. IN MID-1961, THE DESIGN TEAM FOUND A SOLUTION TO THE PROBLEM: THE SHELLS ALL BEING CREATED AS SECTIONS FROM A SPHERE. THIS SOLUTION ALLOWS ARCHES OF VARYING LENGTH TO BE CAST IN A COMMON MOULD, AND A NUMBER OF ARCH SEGMENTS OF COMMON LENGTH TO BE PLACED ADJACENT TO ONE ANOTHER, TO FORM A SPHERICAL SECTION.
  42. 42. SYDNEY OPERA HOUSE: CONSTRUCTION:
  43. 43. SYDNEY OPERA HOUSE: FINISHES: ACTUAL CLAY, BRICK, AND STONE VENEER GRANITE OR MARBLE CLADDING EXPOSED AGGREGATE FINISH SAND BLASTED FINISH FORM LINER PATTERNS THE SYDNEY OPERA HOUSE USES WHITE GLAZED GRANITE TILES. 1,056,000 TILES WERE USED TO COVER THE MASSIVE STRUCTURE.
  44. 44. Introduction: • Baha’i Faith • A temple in the capital city of India • Architect Mr. Fariborz Sahba was selected by the world governing body of Baha’i faith, “ The Universal House of Justice” in the year 1974 • Flint & Neill partnership of London was the consultancy • ECC construction group of Larsen & Toubro Ltd. were the contractors • Design process for the structure began in the year 1976 Components of the structure: • Main building consisting of Basement Three groups of Nine shells springing from the podium Double layered Interior dome Nine arches Nine ponds Walkways
  45. 45. Model of the Lotus temple
  46. 46. • Interior dome is 28 m in height and 34m in diameter • Inner leaves are of 200 mm thick and of 33.6 m in height • Outer leaves are of 135 mm from their cusps to the line of glazing, beyond which they thicken to 250 mm and of 22.5 m in height • Entrance leaves are of 150 mm at center to 300 mm thick at their edges and of 7.8 m in height • Shells within the interior dome: 60mm thick Analysis & Design of Structural components: • Spherical surfaces for the Entrance & Outer leaves • Arch soffits have a Parabolic cone shape • Spheres, cylinders, toroids & cones for Inner leaves • Nine intersecting spheres form interior dome • Final geometrically converted shapes were so complex that it took the designers over two & a half years to complete the detailed drawings of the temple. • In-situ Reinforced Concrete construction
  47. 47. Cladding: • Shells & arches are clad in white Greek marble panels, preformed in Italy to the surface profiles and to patterns related to the geometry by Marmi Vicentini S.P.A Company. • The panels are fixed by means of stainless steel brackets secured by bolts in holes drilled after concreting and the joints were filled with molded rubber cordon & silicon sealant was applied over it. • Floor finishes were also of white marble • Balustrades, stairs were precast • Stones used for stairs were made of red sandstone. • Complete construction of the structure was completed in the year 1986.
  48. 48. PNUEMATIC STRUCTURES • An air-supported or air-inflated structure which consists of internal pressurized air i.e. structural fabric envelope. • Air is the main support of the structure, and where access is via airlocks. • It is usually dome-shaped, since this shape creates the greatest volume for the least amount of material. • The materials used for air-supported structures are similar to those used in tensile structures, namely synthetic fabrics such as fibre glass and polyester. • In order to prevent deterioration from moisture and Ultraviolet radiation, these materials are coated with polymers such as PVC and Teflon.
  49. 49. PNEUMATIC STRUCTURES AIR SUPPORTED PNUEMATIC STRUCTURE
  50. 50. PNEUMATIC STRUCTURES Advantages: • Considerably lower initial cost than conventional buildings • Lower operating costs due to simplicity of design. • Easy and quick to set up, dismantle, and relocate . • Unobstructed open interior space, since there is no need for columns • Able to cover almost any project • Custom fabric colours and sizes, including translucent fabric, allowing natural sunlight in.
  51. 51. PNEUMATIC STRUCTURES Disadvantages: • Continuous operation of fans to maintain pressure, often requiring redundancy or emergency power supply. • Dome collapses when pressure lost or fabric compromised • Cannot reach the insulation values of hard-walled structures, increasing heating/cooling costs • Limited load-carrying capacity • Conventional buildings have longer lifespan
  52. 52. THANK YOU

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