SURFACE ACTIVE SYSTEMS

Folded Plate Structure

Shell Structure

Barrel Vault

Dome

HYPERBOLIC PARABOLOID

PRESENTED BY- ANUJA MNAHID SPOONAM TPURVA RANKITA GPAYAL CRISHIKESH KDHAMMJYOTIROHAN SPOONAM T

FOLDED PLATES STRUCTURES

They are assemblies of flat plates, or slabs,

inclined in different directions and joined along

their longitudinal edges.

It is capable of carrying loads without the need

for additional supporting beams along mutual

edges.

Uses:

to construct roofs for industrial

warehouses and public buildings.

Material used:

cast in situ or precast reinforced concrete,

or steel plate.

Simple formwork required, and usually use less

material.

They have an intrinsic rigidity and high load-

carrying capacity which makes them

economical over long spans.

Fig.1

Fig.2

The Principle 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

Structural Condition Of Folding Structures.

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.

Types of Folded Structure

Based on geometric shape folded structures

can be divided into:

Folded plate frames structures

Folded plate surfaces structures

folded plate structuresFig.5

Fig.6 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

Folded structures of glass

Folded constructions made in

combination

of different materials

Fig.8

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

THE APPLICATION OF FOLDED STRUCTURES

As Roof Structure As Wall Structure

As Steel Sheet Piles As Floor Structure

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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

SHELL STRUCTURE

TYPES OF SHELL ROOF FORMS

Conoid shell Square dome

Hyperboloid of revolution 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

Materials-

Actual 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 massive structure.

Fig :Plan Fig :Framing

Fig :Sydney opera house steel reinforcing fig :Use of tiles

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

Wall-

Nonloadbearing 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 Technology-

Projection of section of arch in plan.

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.

Fig: semicircular arch

Starting the horizontal courses Laying 3-

5mm mortar

Pressing the block on site

Filling the joints Horizontal courses Starting arch window

Building vertical

courses Casting waterproof

earth plaster

Laying bottom

side blocks of

the window

Completing bottom

side blocks

Window arch

completed

Arch of the window

being build with the

help of reverse

centering

WHAT ARE DOMES ?

DOME, IN ARCHITECTURE, HEMISPHERICAL STRUCTURE EVOLVED

FROM THE ARCH, USUALLY FORMING A CEILING OR ROOF.

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.

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.

THE SHAPE OF THE DOME ENCLOSES THE MAXIMUM AMOUNT OF

SPACE WITH THE LEAST SURFACE AREA.

Edna, texas Internal view

SOME OF THE TERMINOLOGY THAT IS OFTEN

ASSOCIATED WITH DOMES INCLUDE:

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

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

Extrados: the outer curve of a dome.

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

top.

Intrados: the inner curve of a dome.

Springing: the point from which the dome rises.

TYPES OF DOMES

DOME AND HEMISPHERE

PARABOLIC DOME HYPERBOLIC DOME

TRANSLATIONAL DOME

VIDHAN SABHA , BHOPAL

Location- bhopal 1982-1996 Architect- charles correa Area- 32000m2 Construction technology-

conventional – in –site- reinforced concrete

Material- indian marble,granite.Red sandstone

ROOF PLAN AND SECTION

Section

Plan

THE STATE ASSEMBLY, IN THE CAPITAL CITY OF BHOPAL HAS BEEN DESIGNED BY ARCHITECT CHARLES CORREA FOR THE GOVERNMENT OF MADHYA PRADESH.

THE VIDHAN BHAVAN IS A HUGE BUILDING, COVERING AN AREA OF MORE THAN 32,000 SQ. METERS OF BUILT SPACE.

SPACES IN VIDHAN SABHA

THE UPPER HOUSE – VIDHAN PARISHAD (75 MEMBERS)

THE LOWER HOUSE – VIDHAN SABHA (231 MEMBERS)

THE COMBINED HALL

LIBRARY

THE SPEAKERS OFFICE

THE CHIEF MINISTER OFFICE

THE CHIEF SECRETARY AND SUPPORTING STAFF OFFICE.

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

SERVICES, UTILITIES, AND PARKING FACILITIES

VIDHAN SABHA (LOWER HOUSE)

• THE MAJOR ATTRACTION IS THE ASSEMBLY HALL.

• 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.

• 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

• ACCESS TO THE HALL IS PROVIDED THROUGH THE

GRAND ENTRANCE RESEMBLING TO SANCHI GATE.

• 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.

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.4.1

Fig 4.2

Section through Altar Construction of roof

Interior of church Axonometric

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 usedA structural planar deck system

A vapor control layer

160mm glass fiber quilt insulation

Aluminum standing-seam roof covering

CONSTRUCTION DETAILS

REFRENCES

https://www.designingbuildings.co.uk/wiki/Folded_plate_construction

www.novotheatre.gov.bd

www.osanbashi.com/en/outline/features.html

THANK YOU !