Shell structure

SHELL STRUCTURE
BY
ARCHIMAN BISWAS
PUJA AGARWAL
PURBITA SAMANTA
SAYANTAN DAS
SUSMITA PAUL

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.

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.

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.

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.

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…

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

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.

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

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.

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.

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

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

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

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.

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.

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.

(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:

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

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) :

THIS HYPERBOLOID STRUCTURE IS THE KOBE TOWER IN JAPAN.

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 :

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 :

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

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

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

PIER LUIGI NERVI PALAZZETTO DELLO
SPORT

A GEODESIC DOME DESIGNED BY BUCKMINSTER FULLER (A NEO FUTURISTIC
ARCHITECT)

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.

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.

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.

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.

SYDNEY OPERA HOUSE:
CONSTRUCTION:

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.

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

• 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

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.

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.

PNEUMATIC STRUCTURES
AIR SUPPORTED PNUEMATIC STRUCTURE

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.

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

Shell structure

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Destacado

Destacado (15)

Similar a Shell structure

Similar a Shell structure (20)

Último

Último (20)

Shell structure