INTRODUCTION
A DOME IS A THIN CURVED SURFACE OBTAINED BY REVOLUTION OF CURVED SURFACE
ABOUT A VERTICAL AXIS. IT IS AN ELEMENT OF ARCHITECTURE THAT RESEMBLES THE HOLLOW
UPPER HALF OF A SPHERE.
-THE THICKNESS OF DOME IS VERY SMALL AS COMPARED TO ITS OTHER DIMENSIONS
-IT VARIES FROM 75MM TO 150MM.
-IT IS VERY ECONOMICAL IF THE COST OF SHUTTERING IS REPETITIVE.
-THEY ARE SUBJECTED TO COMPRESSIVE STRESSES ONLY.
-IT CAN BE CIRCULAR OR CONICAL AND THIS CAN BE OBTAINED
BY REVOLUTION OF SEGMENT OF A CIRCLE OR A SLANTING LINEABOVE VERTICAL AXIS.
-A FIBRE IN A DOME IS SUBJECTED TO MERIDINAL THRUST
AND HOOP STRESS IN THE DIRECTION OF MERIDIANS AND
LATITUDES RESPECTIVELY.
-AT THE FREE EDGE OF THE DOME,MERIDINAL STRESSES HAVE
HORIZONTAL COMPONENT WHICH IS TAKEN CARE BY
PROVIDING A RING BEAM WHICH IS SUBJECTED TO HOOP
TENSION.
EVOLUTION OF DOMES
•THE EARLIEST DOMES WERE LIKELY DOMED HUTS MADE FROM SAPLINGS, REEDS,
OR TIMBERS AND COVERED WITH THATCH,TURF OR SKINS.
•THE EARLIEST DISCOVERED REMAINS OF DOMED
CONSTRUCTIONS MAY BE FOUR SMALL DWELLINGS
MADE OF MANMOTH TUSKS AND BONES.
THE FIRST WAS FOUND BY A FARMER IN UKRAINE,
IN 1965 WHILE HE WAS DIGGING IN HIS CELLAR AND
ARCHAEOLOGISTS UNEARTHED THREE MORE.
•DURING NEOLITHIC PERIOD IN THE ANCIENT NEAR EAST,
SMALL DOMES IN CORBELLED STONE OR BRICK OVER
ROUND-PLAN HOUSES WERE SERVED AS DWELLINGS FOR POORER PEOPLE BUT
DOMES DID NOT PLAY AN IMPORTANT ROLE IN MONUMENTAL ARCHITECTURE.
•ANCIENT STONE CORBELLED DOMES HAVE BEEN FOUND
FROM THE MIDDLE EAST TO WESTERN EUROPE.
CORBELLED BEEHIVE DOMES WERE USED AS GRANARIES
INANCIENT EGYPT, IN MASTABA TOMBS OF THE OLD
KINGDOM FROM THE FIRST DYNASTY, AS PRESSURE-
RELIEVING DEVICES IN PRIVATE BRICK PYRAMIDS OF
THE NEW KINGDOM.
CORBEL DOMES - THOLOS OF
ATREUS
• THE CONSTRUCTION OF THE FIRST TECHNICALLY ADVANCED TRUE
DOMES BEGAN IN THE ROMAN ARCHITECTURAL REVOLUTION
TO SHAPE LARGE INTERIOR SPACES OF TEMPLES AND PUBLIC
BUILDINGS, SUCH AS THE PANTHEON.
•SQUINCHES, THE TECHNIQUE OF MAKING A TRANSITION FROM
A SQUARE SHAPED ROOM TO A CIRCULAR DOME, WAS MOST
LIKELY INVENTED BY THE ANCIENT PERSIANS.
•THE ONION DOME BECAME ANOTHER
DISTINCTIVE FEATURE IN THE RUSSIAN
ARCHITECTURE, OFTEN IN COMBINATION
WITH THE TENTED ROOF.
PANTHEON
ANCIENT-ONE OF THE OLDEST TECHNIQUES OF EARTH ARCHITECTURE IS THE BRICK STRATEGY,
WHICH WAS OFTEN USED TO CONSTRUCT BRIDGES AND ARCHES.
•IN THIS TECHNIQUE, CONCRETE, BRICK OR STONE ARE PUT ON TOP OF A WOODEN FRAME,
WHICH IS MOLDED ACCORDING TO THE DESIRED SHAPE.
•THE MOLD HELPS IN HOLDING THE STONE OR BRICK IN PLACE UNTIL IT SETTLES AND
SUPPORTS THE WHOLE STRUCTURE.
MODERN- THE STRESSED SKIN TECHNIQUE IS A MORE MODERN BUILDING METHOD.
• THIS USES METAL OR FIBERGLASS PANELS RIVETED TOGETHER.
• THE METHOD SAVES COSTS AND DOESN’T REQUIRE ANY BEAMS OR SUPPORT STRUCTURE.
HOWEVER, TO PREVENT ANY KIND OF CONDENSATION, IT BECOMES NECESSARY TO
INSTALL INSULATORS IN THE STRUCTURE.
• THE MONOLITHIC, YET MODERN TYPE OF DOME CONSTRUCTION IS MADE OF THREE
PHASES. THIS INVOLVES USING A SPECIAL TYPE
OF MEMBRANE THAT IS INFLATED AND
PLACED ON THE DOME, GIVING IT A FINISH
THAT SERVES LIKE A WEATHER-PROOF SKIN,
BUT THAT CAN ALSO BE DAMAGED VERY
EASILY.
• HOWEVER, THE MATERIALS USED IN THE
PROCESS ARE NOT ENVIRONMENTALLY
FRIENDLY AS THEY HAVE OIL-BASED CHEMICALS.
ANCIENT AND MODERN TECHNIQUES FOR CONSTRUCTION OF DOMES :
HISTORY:
➢ THE CONSTRUCTION OF THE FIRST TECHNICALLY ADVANCED
TRUE DOMES BEGAN IN THE ROMAN ARCHITECTURAL
REVOLUTION TO SHAPE LARGE INTERIOR SPACES
OF TEMPLES AND PUBLIC BUILDINGS, SUCH AS
THE PANTHEON.
➢ SQUINCHES AND PENDENTIVES, THE TECHNIQUE OF MAKING
A TRANSITION FROM A SQUARE SHAPED ROOM TO A
CIRCULAR DOME, WAS MOST LIKELY INVENTED BY THE
ANCIENT PERSIANS.
➢ THE ONION DOME BECAME ANOTHER DISTINCTIVE FEATURE
IN THE RUSSIAN ARCHITECTURE, OFTEN IN COMBINATION
WITH THE TENTED ROOF.
➢ CORBEL DOMES AND TRUE DOMES HAVE BEEN FOUND IN
THE ANCIENT MIDDLE EAST IN MODEST BUILDINGS AND
TOMBS.
PANTHEON
TAJCORBEL DOMES - THOLOS OF
TYPES OF DOME :
CORBEL DOME:
o EARLIEST DOME FORMS
o IT IS FORMED BY HORIZONTAL
MASONRY CONSTRUCTIONS
THAT GRADUALLY DECREASE
IN SIZE TO CREATE A
SEMI-SPHERICAL SHAPE
ONION DOME:
o THE ONION DOME IS A
BULBOUS DOME THAT
WIDENS FROM A SMALL BASE
AND THEN TAPERS TOWARD
THE TOP, SIMILAR TO THE
DOME OF THE TAJ MAHAL
DRUM DOME:
o COMMON DOME SHAPE
o SIMPLE SEMI-SPHERICAL
SHAPE THAT EXTENDS UP
FROM A CIRCULAR BASE.
EG.PANTHEON
CORBEL DOME - THOLOS OF
ATREUS
ONION DOME – TAJ MAHA
DRUM
DOME-PANTHEON
OVAL DOME:
o THE OVAL DOME HAS AN OVAL OR EGG-SHAPED BASE
AND EXTENDS UPWARD MUCH LIKE A SPHERICAL
DOME.
o EG: BAROQUE OR LATE RENAISSANCE BUILDINGS
SAUCER DOME:
o CIRCULAR BASED DOMES
o CREATE A LOW-PITCHED SHAPE THAT LOOKS MORE
LIKE AN INVERTED SAUCER THAN A HALF SPHERE.
UMBRELLA DOME:
o ALSO CALLED AS SCALLOPED DOME.
o THE WEIGHT OF THE DOME IS SUPPORTED BY
VERTICAL STRUCTURES THAT GO FROM THE BASE TO
THE CENTER, DIVIDING THE DOME INTO SEGMENTS.
GEODESIC DOME:
o A GEODESIC DOME IS A SPHERICAL OR
PARTIAL-SPHERICAL SHELL STRUCTURE OR LATTICE
SHELL BASED ON A NETWORK OF GREAT
CIRCLES (GEODESICS) ON THE SURFACE OF A SPHERE.
o THE GEODESICS INTERSECT TO
FORM TRIANGULAR ELEMENTS THAT HAVE LOCAL
TRIANGULAR RIGIDITY AND ALSO DISTRIBUTE
THE STRESS ACROSS THE STRUCTURE.
OVAL
DOME
SAUCER
DOME
UMBRELLA
DOME
FORCES ACTING ON DOMES:-
1)SELF WEIGHT OF THE SURFACE
2)UNIFORMLY DISTRIBUTED LIVE LOAD
3)WIND LOAD
4)LOAD OF THE UPPER EDGE
•DOMES ARE ALSO CHARACTERIZED BY A THRUST.
•THE DOME’S THRUST IS COMPOSED OF ITS WEIGHT AND
THE HORIZONTAL THRUST OF THE BASIC ARCH SECTION.
•EDGE FORCES ARE TANGENTIAL TO THE SURFACE OF THE
SHELL AND CAN THEREFORE BE SUPPORTED BY A BUTTRESS
(MERIDIONAL FORCES) OR BY RING BEAM.
•DOME IS CREATED BY THE ROTATION OF AN ARCH AROUND
A VERTICAL AXIS, ANOTHER FORCE IS ACTING IN IT: THE
CIRCULAR FORCE (CF) OR HOOP FORCE WHICH ACTS IN
LATITUDINAL DIRECTION.
UNLIKE AN ARCH, A DOME CAN RESIST OUT-OF-PLANE
BENDING BECAUSE OF INTERNAL HOOP FORCES
•HOOP FORCES ALLOW RING-BY-RING CONSTRUCTION OF A
MASONRY DOME, AN UNFEASIBLE TASK FOR AN ARCH. AS A
RESULT, THOUGH AN ARCH IS UNSTABLE WITHOUT ITS
KEYSTONE, A DOME WITH AN OCULUS IS PERFECTLY STABLE
FORCES ACTING IN DOMES
ROUGH PLAN
OF RING BEAM
RING BEAM REINFORCEMENT
•THE DOME CAN BE ASSIMILATED TO AN INFINITESIMAL
NUMBER OF ARCHES WHOSE THRUST RADIATES FROM THE
CENTRE TOWARDS THE PERIPHERY.
•ON THE SPRINGER LEVEL, THE COMBINATION OF ALL THESE
HORIZONTAL THRUSTS WILL CREATE A PERIPHERAL TENSION
(PT) WHICH WILL TEND TO OPEN THE WALL SUPPORTING THE
DOME.
•THE COMBINATION OF THE MULTITUDE OF CIRCULAR FORCES
AND LINES OF THRUST WILL CREATE A NET OF COMPRESSION
FORCES WHICH WILL DEVELOP ON THE ENTIRE SURFACE OF
THE DOME.
•THEREFORE, IT CAN RESIST TREMENDOUS STRESS.
•IN CASE OF FAILURE OF ANY PART OF THE DOME, UNDER AN
EXCEPTIONAL STRESS, THIS NET OF COMPRESSIVE FORCES WILL
FIND ANOTHER WAY TO ACT IN THE DOME, AND THE LATTER
WILL RARELY COLLAPSE ENTIRELY AS LONG AS THE SUPPORTS
(WALLS OR COLUMNS) ARE INTACT.
CF = Circular force in every ring
LT = Line of thrust of “an arch” of
the dome
HT = Horizontal thrust of “an
arch” of the dome
W = Vertical weight of “an arch”
and the overload
T = Thrust, resultant force of the
horizontal thrust and weight of
“an arch”
P = Peripheral tension which is
created by the combination of
the horizontal thrusts of all the
arches, that are radiating from
the centre
•THEY CAN BE BUILT EITHER
ON CIRCULAR OR
QUADRANGULAR PLANS.
STABILITY OF DOMES
• THE EXAMPLES OF DOMES BUILT ALL OVER THE WORLD
THROUGH THE AGES SHOW THAT DOMES CAN HAVE A WIDER
VARIETY OF SHAPES THAN VAULTS.
•FOR INSTANCE, A DOME CAN BE CONICAL WITH ANY
PROPORTIONS: FROM A SHARP ONE TO A FLATTER ONE.
•BUT IT IS OBVIOUS THAT AN ARCH CANNOT HAVE A TRIANGULAR
SECTION
•THEREFORE, IT APPEARS THAT IF ARCHES OR VAULTS ARE
STABLE, DOMES OF THE SAME SECTION WILL NECESSARILY BE
STABLE. BUT THE OPPOSITE IS NOT NECESSARILY TRUE, AS WE
HAVE SEEN WITH THE CASE OF THE CONICAL DOME AND THE
TRIANGULAR ARCH.
Conical circular dome
Triangular arch
•THE MORE THE RISE OF
DOME (OR ARCH) AS
COMPARED TO THE SPAN,
THE MORE STRONGER IT IS.
•THEREFORE CATENARY
DOMES ARE MORE STABLE
AND REQUIRE LESS
SUPPORT THAN THE
SEGMENTAL DOMES.
•SOMETIMES, WHEN LOADED, THE DOME MAY NOT COINCIDE WITH
THE LINE OF PRESSURE.
•THEREFORE, AN ADDITIONAL FORCE IS REQUIRED TO RESIST BENDING.
•THAT IS TO ADD HOOP COMPRESSION RINGS WHICH PROVIDE THE
HORIZONTAL FORCE NEEDED.
•WAY TO CREATE A DOME WITHOUT HOOP COMPONENTS IS TO USE
RIBS THAT ARE COMPOSED OF TRUSSES, AS IS FOUND IN MANY STEEL
DOME SYSTEMS.
•WITH THIS DESIGN IT IS USEFUL TO ADD A COMPRESSION RING
TOWARDS THE TOP OFTHE DOME TO COUNTER THE INWARD TRUSS
TRUSSED DOME WITH COMPRESSION RING
LINE OF PRESSURE
•THE PURPOSE OF THREE-DIMENSIONAL COMPRESSION SYSTEMS IS TO CREATE A LARGE,
UNOBSTRUCTED INTERIOR SPACE THAT CAN BE UTILIZED IN A NUMBER OF WAYS.
•IT USES COMPRESSIVE FORCES TO TRANSFER THE LOAD FROM THE TOP OF THE DOME
DOWN ALONG THE MEMBERS WHICH SUPPORT THE SYSTEM.
•SOME COMMON DOME SHAPES ARE:
OVERVIEW
1. CONICAL DOME 2. SQUARE DOME
3. ELLIPTICAL DOME
3. ELLIPTICAL DOME
IN SECTION WITH
THE USE OF A TRUSS
SYSTEM TO BEAR THE
LOAD.
1. THE CONICAL DOME
SHOWS A SERIES OF RIBS
THAT TRANSFER THE
LOAD DOWN THE
STRUCTURE TO THE
SUPPORTS BELOW.
2. THE SQUARE DOME RESTS
ON TOP OF PENDENTIVES,
WHICH CONNECT THE
BOTTOM RIM OF THE DOME
TO THE ARCHES ON WHICH
IT RESTS.
TRUSSED RIB
(SECTION)
PLAN
•REINFORCED CONCRETE COMBINES PROPERTIES OF STEEL
AND CONCRETE TO RESIST BOTH TENSION AND
COMPRESSION.
•ONE OF THE LARGEST REINFORCED CONCRETE DOMES
MEASURES 663 FEET (202METERS).
•SOME EXAMPLES OF REINFORCED CONCRETE DOMES ARE
THE KING DOME IN SEATTLE (DISMANTLED IN 2000) AND THE
ALGECIRAS MARKET IN SPAIN.
1. REINFORCED CONCRETE
TYPES OF DOMES BASED ON MATERIALS
THE KING DOME
. THE ALGECIRAS MARKET
•ONE OF THE LARGEST CONSTRUCTED STEEL
DOMES MEASURES 713 FEET (218
METERS).SOME EXAMPLES OF STEEL DOMES
ARE THE ASTRO DOME IN HOUSTON AND
THE OSAKADOME IN JAPAN.
2. STEEL
•STEELDOMES USE THREE-DIMENSIONAL TRUSSES AND HAVE A
LIGHTER CONSTRUCTION THAN CONCRETE DOMES.
•STEEL HANDLES COMPRESSION AND TENSION BETTER THAN
CONCRETE DOES.
•LARGER DOMES USE STEEL BECAUSE IT CAN HAVE A GREATER SPAN
MORE EASILY THAN CONCRETE.
3. WOOD
•WOODEN DOMES ARE MADE OF WOOD COMPOSITES
COMBINED WITH JOINTS AND STEEL FRAMES.
•WOODEN DOMES ARE FAVORED FOR THE WARMTH OF THE
WOOD ITSELF, BUT THEY CANNOT SPAN DISTANCES LIKE
CONCRETE OR STEEL.
•ONE OF THE LARGEST WOODEN DOMES MEASURES 584
FEET (178 METERS).
•SOME EXAMPLES OF WOODEN DOMES ARE THE TACOMA
DOME IN WASHINGTON AND THE ODATE JUKAI DOME IN
JAPAN.
4. MASONRY
•MASONRY WAS USED IN EARLY DOME
CONSTRUCTION BECAUSE IT WAS WIDELY AVAILABLE.
•MASONRY DOMES HAVE THE SMALLEST SPAN OF ALL
THE MATERIALS MEASURING, AT LARGEST, 141 FEET
(43 METERS).
•SOME EXAMPLES OF MASONRY DOMES ARE THE
PANTHEON IN ROME AND ST. PAUL’S CATHEDRAL IN
LONDON.
NUMERIC PARAMETERS
•THE SMALLEST SPANS ARE ACHIEVED BY USING MASONRY BECAUSE THE WEIGHT OF THE
MATERIAL IS LARGE AND THE STRENGTH IS LOWER.
•STEEL PROVIDES THE LARGEST SPANS BECAUSE LESS MATERIAL IS NEEDED AND THEREFORE
THE STRUCTURE ITSELF WEIGHS LESS. ADDITIONALLY STEEL PROVIDES A HIGH MATERIAL
STRENGTH.
•GEODESIC DOMES HAVE BEEN WIND-TUNNEL TESTED TO WITHSTAND WIND SPEEDS UP TO
200 MPH.
BASIC STEPS INVOLVED IN THE CONSTRUCTION OF DOME:-
2)MARK THE CENTER POINT AND INSERT THE
TRAMMEL.
5)BUILD THE SIDES
4)THE PIVOT WILL RISE AS THE DOME
RISES.
3)CREATE A PIVOT TO KEEP THE DOME IN
LINE.
1)START WITH A FOUNDATION
BRICK MASONRY DETAIL:-
-THIS IS HEMISPHERICAL
DOME WITH CONSTANT
RADIUS WITH THE HELP OF
TRAMMEL.
DOME MASONRY WORK
CONSISTS OF FOLLOWING
STEPS:-
-FINDING AND FIXING THE
CENTER POINT OF THE
DOME RADIUS IN RELATION
TO THE LEVEL LINE.
-LAYER BY LAYER SETTLING
OF DOME MASONRY,WITH
THE BRICKS SET IN MORTAR
POSITIONED AND ALLIGNED WITH THE TRAMMEL
AND TAPPED FOR PROPER SEATING.
-IN UPPER PART OF THE DOME, WHEN THE TRAMMEL
IS STANDING AT STEEPER ANGLE THAN 45 DEGREE,THE
BRICKS MUST BE HELD IN PLACE UNTIL EACH COURSE
IS COMPLETE.
-COURSES ARE INHERENTLY STABLE AND THEREFORE
NEED NOT TO BE HELD IN PLACE ANY LONGER.
ENSURE THAT:-
- TROWELLING IS DONE VIGROUSLY( TO INSURE
COMPACT RENDERING)
- ALL EDGES AND CORNERS ARE ROUNDED OFF
- THE RENDERING IS ALLOWED TO SET/DRY
SLOWLY (KEEP SHADED AND MOIST,AS
NECESSARY)
- THE MATERIAL COMPOSITION IS SUITABLE
AND MUTUALLY COMPATIBLE.
RING BEAM
HOOPS
MERIDIAN
RCC DOME DETAIL :-
-MERIDIONAL THRUST ACTING VERTICALLY AND HOOP STRESS ACTING HORIZONTALLY
-TYPICAL SPAN= 250’-650’
-CONCRETE IS THICK NEAR THE EDGE OF THE RING BEAM AND TAPERS AS IT GOES
UPWARDS.
RING BEAM
HOOPS
MERIDIAN
STEPS FOR CONSTRUCTION OF MONOLITHIC DOME:-
MATERIALS REQUIRED:-
1)STEEL-REINFORCED CONCRETE
2)POLYURETHANE FOAM INSULATION
3)INFLATABLE AIRFORM
STEPS:-
1=DOME STARTS AS A CONCRETE RING
FOUNDATION,REINFORCED WITH STEEL REBAR.VERTICAL
STEEL BARS EMBEDDED IN THE RING LATER ATTACHED TO
THE STEEL REINFORCING OF THE DOME ITSELF.
2=AN AIRFORM,FABRICATED TO THE PROPER SHAPE AND
SIZE IS PLACED ON THE RING BASE. USING BLOWER FANS, IT
IS INFLATED AND THE AIRFORM CREATES THE SHAPE OF THE
STRUCTURE TO BE COMPLETED. THE FANS RUN
THROUGHOUT THE CONSTRUCTION OF THE DOME.
3=POLYURETHANE IS APPLIED TO THE INTERIOR SURFACE OF
THE AIRFORM.ENTRANCE INTO THE AIRFORM IS MADE
THROUGH A DOUBLE DOOR AIRLOCKWHICH KEEPS THE AIR
PRESSURE INSIDE AT A CONSTANT LEVEL.
APPROXIMATELY 3 INCHES OF FOAM IS APPLIED.THE FOAM
IS ALSO THE BASE
FOR ATTACHING THE STEEL REINFORCING REBAR.
4=STEEL REINFORCING REBAR IS ATTACHED TO THE
FOAM USING A SPECIALLY ENGINEERED LAYOUT OF
HOOP(HORIZONTAL) AND VERTICAL STEEL REBAR.
SMALL DOMES NEED SMALL DIAMETER BARS WITH
WIDE SPACING. LARGE DOMES NEED LARGE BARS
EITH CLOSER SPACING.
5=SHOTCRETE- A SPECIAL SPRAYMIX OF CONCRETE-
IS APPLIED TO THE INTERIOR SURFACE OF THE
DOME. THE STEEL REBAR IS EMBEDDED IN THE
CONCRETE AND WHEN ABOUT 3 INCHES OF
SHOTCRETE IS APPLIED,THE MONOLITHIC DOME IS
FINISHED.THE BLOWER FANS ARE SHUT OFF AFTER
THE CONCRETE IS SET.
CASE STUDY OF R.C.C. DOME
ST.FRANCIS XAVIER CHURCH, UDYAVARA IN UDUPI
UMBRELLA SHAPED DOME
(UNDER CONSTRUCTION)
RING BEAM
40FT.(12.192M)
• HT. OF DOME: 40FT.(12.192M)
• DIA. OF DOME: 36FT.(10.9782M)
REINFORCEMENT BARS OVER
THE SCAFFOLDING
M25 GRADE
CONCRETE DOME
• 4FT. (1.2192M) OF CONCRETE IS LAID
PER DAY
CASE STUDY OF R.C.C. DOME
•DOME OF DHYANALINGA MEDITATION SHRINE IS SITUATED IN ISHA YOGA CENTRE,
COIMBATORE.
•THE DHYANALINGA IS A MULTI-RELIGIOUS MEDITATION SHRINE CREATED EXCLUSIVELY FOR
THE PURPOSE OF MEDITATION.
•THIS DOME OF 22.16 M DIAMETER HAS
DESIGNED BY THE AUROVILLE EARTH
INSTITUTE.
•IT HAS BEEN BUILT FREE SPANNING IN 9 WEEKS.
•THE WORK ON THE DOME STARTED THE 21ST
NOVEMBER 1998 WITH THE CONSTRUCTION OF
THE ENTRANCE VAULT, BUILT WITH GRANITE
STONES AND ON A CENTERING DOME WITH
LATERITE BLOCKS.
•THE DOME HAD TO BE COMPLETED BEFORE A CERTAIN DEADLINE RELATED WITH HIS
YOGIC PRACTICES AND PLANETARY ASPECTS
CASE STUDY OF BRICK DOME
• THE TIME REQUESTED FOR THE PRODUCTION, CURING AND DRYING OF THE BLOCKS (3 - 4
MONTHS COMPULSORY FOR ARCHES, VAULTS AND DOMES) WOULD HAVE BEEN TOO LONG.
THUS, THE CHOICE WENT FOR FIRED BRICKS, WHICH WERE LAID WITH A STABILISED EARTH
MORTAR.
• THE FOUNDATIONS AND WALLS WERE BUILT IN RANDOM RUBBLE MASONRY WITH GRANITE
STONES IN LIME MORTAR.
•AROUND 214,000 FIRED BRICKS WERE LAID AND THE CONSTRUCTION SITE HAD A
WORKING FORCE OF MORE THAN 220 .
•THE LARGE AMOUNT OF FIRED BRICKS REQUIRED COULD NOT BE SUPPLIED BY THE SAME
BRICK FACTORY. THEREFORE THE FIRED BRICKS CAME FROM ABOUT 20 DIFFERENT KILNS.
AS A RESULT, THEY HAD DIFFERENT SIZES AND MOST OF THE TIME THEY HAD ODD SHAPES
THEREFORE, NEARLY 200,000 BRICKS HAD TO BE CHECKED ONE BY ONE.
•NO REINFORCE CONCRETE HAD BEEN USED IN
ANY PART OF THE BUILDING: NEITHER FOR THE
FOUNDATIONS, PLINTH NOR TIE FOR THE DOME.
•THE DOME PRESENTS THESE FEATURES:
• SECTION: SEGMENTAL ELLIPSE OF 22.16 M
DIAMETER AND 7.90 M RISE.
• THICKNESS: 4 COURSES FROM THE SPRINGER
TO THE APEX: 53 CM, 42 CM, 36.5 CM AND 21
CM AT THE TOP.
• WEIGHT: AROUND 570 TONS (BRICK DOME =
± 420 TONS + GRANITE STONE TO LOAD THE
HAUNCHES = ± 150 TONS).
DOME STABILITY STUDY
•THEY DID NOT WANT TO USE CONCRETE RING BEAMS AND THEREFORE THE METHOD
DOES NOT DEFINE THE OPTIMISED LINE OF THRUST IN THE DOME BECAUSE IT DOES NOT
TAKE IN ACCOUNT THE CONCENTRIC FORCES, WHICH ARE ACTING IN A DOME AND
ALLOW BUILDING IT WITHOUT SUPPORT.
•FINALLY THE DOME WAS STUDIED LIKE A VAULT, WHICH IS MORE SENSITIVE TO A
WRONG SHAPE THAN A DOME: IF A VAULT IS STABLE, A DOME WILL BE STABLE.WHEN
THE OPPOSITE IS NOT NECESSARILY TRUE.
•AS NO REINFORCED CONCRETE WAS USED FOR ANY TIE, IT WAS COMPULSORY TO GET
THE RESULTANT OF THE TRUST WITHIN THE MIDDLE THIRD OF THE RING WALL AND THE
FOUNDATIONS. TO DO SO, GRANITE STONES WERE USED TO LOAD THE HAUNCH OF THE
DOME.
MORTAR SPECIFICATIONS
•WITH THE DOME RISING, THE MORTAR SPECIFICATION NEEDED REGULARLY TO BE ADAPTED:
ADDING MORE SOIL, IN 3 STEPS, SO AS TO HAVE THE IDEAL ADHESION ACCORDING TO THE
ANGLE OF THE LAYERS.
•THE DIFFERENT MORTARS WERE OVER STABILISED SO AS TO GET A FAST SETTING AND
STRENGTH: 13 TO 13.37% OF CEMENT AND 19% OF LIME.
CONSTRUCTION DETAILS OF THE DOME
STARTING THE ENTRANCE VAULT WITH
GRANITE BLOCKS
BLOCK TOUCHING THE SPRINGER
AT THE INTRADOS
KEYSTONE TOUCHING AT THE INTRADOS
BEGINNING THE DOME
DOME WITH THE LINGA AND THE ROPES
TO CHECK THE ELLIPTICAL SHAPE
LAYING KEYSTONES
GROUTING THE STABILISED EARTH GLUE IN THE
JOINTS FILLING TIGHTLY MORTAR WITH STONE CHIPS STARTING THE DOME WITH 29 CM THICK BLOCKS
BONDS OF THE COURSES
GRINDING THE PARTS OF THE COURSE
WHICH ARE TOO HIGH
CHECKING THE LEVEL OF THE COURSES
CLOSING THE PIPE OF AN
ACOUSTIC CORRECTOR
PLASTERING THE PARTS OF THE
COURSE WHICH ARE TOO LOW
INSERTING THE PIPE FOR AN ACOUSTIC
CORRECTOR TO ABSORB 220 HZ
LOADING THE HAUNCHES WITH
GRANITE STONES
SMOOTHENING THE EARTH
CONCRETE WITH A STABILISED
EARTH PLASTER
LAYING THE LAST COURSES DOME NEAR COMPLETION DOME AFTER COMPLETION