Surface Active

SURFACE ACTIVE SYSTEMS 

Folded Plate Structure

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Shell Structure

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Barrel Vault

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Dome

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HYPERBOLIC PARABOLOID

FOLDED PLATES STRUCTURES 

They are assemblies of flat plates, or slabs, inclined in different directions and joined along their longitudinal edges.

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It is capable of carrying loads without the need for additional supporting beams along mutual edges.

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Uses:  to

construct roofs for industrial warehouses and public buildings.

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Fig.1

Material used:  cast

in situ or precast reinforced concrete, or steel plate.

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Simple formwork required, and usually use less material.

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They have an intrinsic rigidity and high loadcarrying capacity which makes them economical over long spans.

Fig.2

inciple of Folding The structural characteristics of folding structures depend on-

 The pattern of the folding.  Their geometrical basic shape.  Its material.  The connection of the different folding plates.  The design of the bearings.

The Basic concept of Folding

Fig.3

Fig.4

Structural Behavior of Folding Load Distribution process :  At first, the external forces are transferred to the shorter edge of one folding element.  There, the reaction as an axial force is divided between the adjacent elements.  Then the forces transferred to the bearings.

Structural Condition Of Folding Structures.

Types of Folded Structure Based on geometric shape folded structures can be divided into: 

Folded plate frames structures

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Folded plate surfaces structures

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folded plate structures

Fig.6

Fig.5

Fig.7

Types of Folded Structure

Classification of folded structures based on the material they are made of:  Folded structures made of reinforced concrete  Metal folded structures  Folded structures of wood

Fig.8

 Folded structures of glass  Folded constructions made in combination of different materials

Fig.9

ADVANTAGES AND DISADVANTAGES OF FOLDED-PLATE STRUCTURE

Advantages:  Very light form of construction. To span 30 m shell thickness required is 60 mm only.  The use of concrete as a building material reduces both materials cost and a construction cost.  Longer span can be provided.  Flat shapes by choosing certain arched shapes.  Esthetically it looks good over other forms of construction.

Disadvantages:    

Shuttering is difficult. Greater accuracy in formwork is required. Good labor and supervision necessary. Rise of roof may be a disadvantage.

CASE STUDY Name of structure-Airship Hangars,Orly (1916-1924) Engineer-Eugene Freyssinet  He designed two large hangars at orly,each 300 meters long,span-86 meters and over 5 metres high.

 It consisted of trough-shaped arches forming continous barrel vaults in form of a parabola with arch profile.  The slab forming the troughs was from 80-200 mm thick,increasing towards base.  The stresses were taken by foundations.  The strength created by folded plate profile reduced reinforcement.

Fig. Airship Hangars,orly

Securing The Foundation Pit With Larsen Planks

Mezzanine ceiling called "Kielsteg"

Church of Notre Dame de Royan, France

Miami Marine Stadium, Florida

THE APPLICATION OF FOLDED STRUCTURES

 As Roof Structure

 As Floor Structure  As Wall Structure

 As Steel Sheet Piles

SHELL STRUCTURE  The term “shell” is used to describe the structures which possess strength and rigidity due to its thin, natural and curved form such as shell of egg, a nut, human skull, and shell of turtle.

 Shell roof shapes divided into 3 parts – Dome Vaults Saddle shapes and conoids  The strength and rigidity of thin,natural,curved shell structures makes its possible to construct single curved barrel vault 60 thick with  span of 30 m  Material- Reinforced concrete as highly plastic material can take any shape when mixed with water  Shell structure are sometime described as single or double curvature shells  Single curvature shells- curved on one linear axis  Double curvature shells- either part of sphere as dome or hyperboloid

TYPES OF SHELL ROOFFORMS Conoid shell

Hyperboloid of revolution

Square dome

Barrel vault shell roof

ADVANTAGES AND DIS-ADVANTAGES OF SHELLS ADVANTAGES-

 Very light form of construction. To span 30.0 m shell thickness required is 60mm  Dead load can be reduced economizing foundation and supporting system  They further take advantage of the fact that arch shapes can span longer  Flat shapes by choosing certain arched shapes  Esthetically it looks good over other forms of construction DISADVANTAGES  Shuttering problem  Greater accuracy in formwork is required  Good labor and supervision necessary  Rise of roof may be a disadvantage

CASE STUDY – OPERA HOUSE     

Location – Australia.1959-1973 Architect- Jon unzone Span –49.987 m Height -65m MaterialsActual clay, brick, and stone veneer Granite or marble cladding Exposed aggregate finish Sand blasted finish Form liner patterns White glazed granite tiles. 1,056,000 tiles were used to cover the mas sive structure.

Fig :Framing

Fig :Plan

fig :Use of tiles

Fig :Sydney opera house steel reinforcing

Fig :Sydney opera house shell ribs

BARREL VAULT SHELL ROOFS  Construction – Thin membrane of reinforced concrete positively curved in one direction so that the vault acts as structure and roof surface. Thickness- 57-75 Span – 12-30 m WallNonloadbearing panel walls of brick, block or timber built between or across columns . Types –

 Short span barrel vault  Long span barrel vault

Stiffening of beams and arches – To avoid distortion of barrel vault stiffening beam and arches are cast integrally with the shell.

 Down stand beam – 150-225 mm thick more efficient because of its depth.  Up stand beam – To avoid interruption of soffit line of vaults.  Arch ribs – less efficient , provided for appearance  Thermal insulation – Thin concrete- poor resistance to transfer heat Use of insulating soffit lining or light weight aggregate screed

Edge and valley beams – Due to self weight and imposed loads thin shell will tend to spread and its curvature flatten out . To resist this reinforced beam are cast between columns as integral part of shell

 Expansion joint – To limit expansion and contraction continuous expansion joint is used at the interval of 30. Concrete shells are covered with non ferrous shee metal, asphalt, bitumen felt, a plastic membrane

STIFFENING BEAMS AND ARCHES FOR BARREL VAULT

CASE STUDY – EARTH INSTITUTE  Location - Auroville  Founded by HUDCO,Government of India in 1989

Semi- circular vault – Span- 6m Length-11m Thickness- 36.5-7cm  Material- Arches, vaults,domes build with compressed stabilased earth blocks without using formwork  Construction TechnologyProjection of section of arch in plan. Fig: semicircular arch Vaulted structures are characterized by acoustic phenomena . Build with free spanning with combination of horizontal and vertical courses. Vault stability calculated without the weight of waterproofing and applied after completion of vault which changes the line of thrust in structure.

Starting the horizontal courses

Filling the joints

Laying 35mm mortar

Horizontal courses

Pressing the block on site

Starting arch window

Arch of the window being build with the help of reverse centering

Window arch completed

Laying bottom side blocks of the window

Building vertical courses

Completing bottom side blocks

Casting waterproof earth plaster

WHAT ARE DOMES ? 

DOME, IN ARCHITECTURE, HEMISPHERICAL STRUCTURE EVOLVED FROM THEARCH, USUALLY FORMING A CEILING OR ROOF.

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A DOME CAN REST UPON A ROTUNDA OR DRUM, AND CAN BE SUPPORTED BY COLUMNS OR PIERS THAT TRANSITION TO THE DOME THROUGH SQUINCHES OR PENDENTIVES.

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THE MAIN OBJECTIVE OF THE STUDY IS TO DESIGN THE STRUCTURAL ELEMENTS OF A DOME STRUCTURE SUCH AS SHELL STRUCTURE,RING BEAM, COLUMN AND FOOTING.

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THE SHAPE OF THE DOME ENCLOSES THE MAXIMUM AMOUNT OF SPACE WITH THE LEAST SURFA CE A REA.

Edna, texas

Internal view

SOME OF THE TERMINOLOGY THAT IS OFTEN ASSOCIATED WITH DOMES INCLUDE:

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Apex: the uppermost point of a dome (also known as the ‘crown’).

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Cupola: a small dome located on a roof or turret.

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Extrados: the outer curve of a dome.

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Haunch: part of an arch that that lies roughly halfway between the base and the top.

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Intrados: the inner curve of a dome.

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Springing: the point from which the dome rises.

TYPES OF DOMES DOME AND HEMISPHERE

HYPERBOLIC DOME

PARABOLIC DOME

TRANSLATIONAL DOME

Location- bhopal 1982-1996 Architect- charles correa Area- 32000m2 Construction technologyconventional – in –site- reinforced concrete  Material- indian marble,granite. Red sandstone    

ROOF PLAN AND SECTION

Section Plan

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THE STATEASSEMBLY, IN THE CAPITAL CITY OF BHOPAL HAS BEEN DESIGNED BY ARCHITECT CHARLES CORREA FOR THE GOVERNMENT OF MADHYAPRADESH.

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THE VIDHAN BHAVAN IS A HUGE BUILDING, COVERINGAN AREA OF MORE THAN 32,000 SQ. METERS OF BUILTSPACE.

SPACES IN VIDHAN SABHA 

THE UPPER HOUSE – VIDHAN PARISHAD (75 MEMBERS)

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THE LOWER HOUSE – VIDHAN SABHA (231MEMBERS)

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THE COMBINED HALL

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LIBRARY

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THE SPEAKERS OFFICE

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THE CHIEF MINISTER OFFICE

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THE CHIEF SECRETARY AND SUPPORTINGSTAFF OFFICE.

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THE MINISTERS AND P.A’S OFFICE (70 NOS.)

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SERVICES, UTILITIES, AND PARKINGFACILITIES

VIDHAN SABHA (LOWER HOUSE) •

THE MAJOR ATTRACTION IS THE ASSEMBLYHALL.

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THE CAPACITY OF HALL IS 231.IT IS CIRCULAR IN PLAN, HAS 15.5 MTS. RADIUS COVERED BY HEMISPHERICAL DOME OF DIA. 31.00MTS AND THICKNESS VARIES FROM 150 TO 90MM THE HEIGHT OF THE CROWN FROM FLOOR IS 25MTS.

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K-13 CELLULOSE FIBER COATING IN 40 MM THICKNESS IS USED TO CONTROL THE ECHO IN THE HALL AND ALSO BROKEN TILES ARE USED ON THE ROOF FOR HEAT INSULATION

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ACCESS TO THE HALL IS PROVIDED THROUGH THE GRAND ENTRANCE RESEMBLING TO SANCHI GATE.

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IT IS PAINTED VERY COLORFULLY REPRESENTING THE PRESENCE OF LORD GANPATI AT ENTRANCE.

CONCRETE HYPERBOLIC PARABOLOID SHELL ROOFS  These can be constructed in reinforced concrete with:• minimum shell thickness of 50mm • Diagonal spans up to 35m  These are cast over a timber form in the shape of required hyperbolic paraboloid format.

TIMBER HYPERBOLIC PARABOLOID SHELL ROOFS  These are usually constructed using laminated edge beams and layers of t and g bording to form the shell membrane.  Roofs with plan size • 6m x 6m - Two layers of boards required • Above 6m x 6m - Three layers of boards required

CASE STUDY- THE CHURCH OF ST.ALOYSIUS,UNITED STATES

 Architect-Erdy McHenry Architecture  The hyperbolic paraboloid roof is used most often as an inexpensive solution to long-span roof requirements.

Fig.4.1  It is used for utilitarian purposes like sports arenas and athletic facilities.  The tent of St. Aloysius church is fabricated from standing seam metal panels.

Fig 4.2

Section throughAltar

Interior of church

Construction of roof

Axonometric

CONSTRUCTION DETAILS To create the overall curve of the building form,a series of

fabricated channels were welded to the 273mm diameter chs top boom of each truss. The channels were rotated to varying degrees to suit the orientation

of the planar deck. A 3mm thick galvanized steel tray was bolted to the top of each

channel and secured with self tapping screws.

Roofing products used A structural planar deck system A vapor control layer 160mm glass fiber quilt insulation Aluminum standing-seam roof covering

REFRENCES

https://www.designingbuildings.co.uk/wiki/Folded_plate_ construction www.novotheatre.gov.bd www.osanbashi.com/en/outline/features.html

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