Lintel and arch

Building Construction and Materials II Assistant Prof. Vinit Rajpurohit

TOPICS TO BE COVERED

LINTELS

•Introduction

•Classification of lintels

ARCHES

•Arches : Terms to be used

•Stability of an arch

•Classification of an arches

BCT

What is Lintel?

A lintel is defined as a horizontal structural member which is placed across the

opening.

Hence, the structure remains in the position by the resistance from the support.

BCT

What is an Arch?

An Arch may be defined as mechanical arrangement of wedge-shaped blocks of

stones or bricks mutually supporting each other and supported at the end by piers

or abutments.

An arch is a structure that spans a space and supports structure and weight below

it.

Arches appeared as early as the 2nd millennium BC in Mesopotamian brick

architecture and their systematic use started with the Ancient Romans who were the

first to apply the technique to a wide range of structures.

BCT

LINTELBAG

SILL

OPENING

Classification of lintel

Lintels are classified into the following types,

according to the materials of their construction:

Timber lintels

Stone lintels

Brick lintels

Reinforced Brick lintels

Steel lintels

Reinforced cement concrete lintels

BCT

Timber lintels

Easily available in hilly area.

Relatively costly, structurally weak and valnerable to fire.

Easily decay, if not properly taken care.

TIMBER LINTEL

BCT

Stone lintels Used , where stones are easily

available. Consists of a simple stone slab

of greater thickness. Due to high cost and its

inability to with stand the transverse stress load.

STONE LINTEL

BCT

Brick lintels

The brick are hard, well burnt , first class bricks .

Suitable for small span. The bricks having frogs

are more suitable.

BRICK LINTEL

BCT

Reinforced Brick lintels

For large spans and heavy loads .

They are reinforced with mild

steel bars.

Very common due to durability,

strength and fire resisting

properties.

Joints are filled with cement

concrete.

BCT

Steel lintels

Provided at large opening and

where the super-imposed loads

are heavy.

It consists of rolled steel joists .

Either used singly or in

combination of two or three

units.

Joint with bolts.

ROLLED STEEL JOIST

BCT

REINFORCED CEMENT CONCRETE

LINTEL

Common in used.

They may be pre-cast .

For smaller span, the pre-

cast concrete lintels are

used.

Depth of lintel depend on

span.

R.C.C. LINTEL

BCT

Basic conceptAn arch is a pure compression form. It can

span a large area by resolving forces into

compressive stresses and, in turn eliminating

tensile stresses. This is sometimes referred to

as arch action. As the forces in the arch are

carried to the ground, the arch will push

outward at the base, called thrust. As the rise,

or height of the arch decreases, the outward

thrust increases. In order to maintain arch

action and prevent the arch from collapsing, the

thrust needs to be restrained, either with

internal ties, or external bracing, such as

abutments.1. Keystone 2. Voussoir 3. Extrados

4. Impost 5. Intrados 6 . Rise

7. Clear span 8. A butment

BCT

Flat Arch ( Jack/Straight Arch)

•Appears to be the most easiest.

•Construction is tricky

•Require skill to make them look good

•Provides support at openings

•efficiently uses the compressive strength of the masonry

Corbelled Arch (False Arch)

•Easiest to construct & Not a true arch

•Not entirely self supporting structure

•Constructed by offsetting successive courses of stone

•Require significantly thickened walls and an abutment of other stone or fill to counteract the effects of gravity.

Triangular Arch (Miter Arch)

•Simple single piece stone laid together.

•The span is limited by the size of the available material.

•Formed by two large diagonal stones that mutually support each other to span an opening.

Different Types Of Arches:

Semicircular Arch

• First created before the Roman times.

• Known as the Roman Arch after the people that brought it to perfection

• A round arch drawn from a single center.

Bullseye Arch (Circular arch)

• Used for windows

• A double arch with two or four keystones.

• Made of two semicircular identical arches.

• The top portion of the circular arches is called The Upper Arch and the lower portion is called The Invert .

Bell Arch

• A Roman arch sat on corbels that are imposts.

• Often carved from one piece of stone.

• Rests on two rounded corbels resulting in a shape somewhat similar to a bell.

Islamic Arch

•Also known the Moorish Arch,

•Defines the feature of Moorish architecture.

Segmental Arch

•Based on a segment of a circle.

•Curve is a less than semicircular segment of a circle.

Foil Arch

•Embellishments of Gothic architecture.

•Also known as Trefoil Arch.


Pointed Islamic Arch

• A pointed variation of the Moorish arch.

Gothic Arch

• The defining feature of the late middle ages in Europe

• Is a sharp-pointed arch.

• Formed of two arc segments (parts of a circle).

Arch based on circular arcs

• There are many varieties of these.

• This one is known as the three centre arch.

Geometrical Arch

• Based on geometrical or mathematical curves.

• Also known an elliptical arch.

Venetian Arch

• A variation of the bell arch.


Ogee Arch

• Based on opposing circular arcs.

• Pointed arch.

• Each side consists of two contrasting curves.

Skewed Arch

• An arch that is not at right angle to the wall it traverses.

• Most famously first used in early railway viaducts.

GEOMETRY BASED ARCHES

1. Flat Arch.

2. Semi-circular Arch.

3. Segmental Arch.

4. Reliving Arch

5. Parabolic Arch.

6. Trefoil Arch.

7. Ogee Arch.

8. Multifoil Arch.

9. Basket handle Arch.

BCT

TYPES of ARCHS

FLAT or JACK ARCHAn arch having a horizontal intrados with voissoirs radiating from a centre

below, often built with a slight camber to allow settling is called a flat

or jack arch.

BCT

French arch: A flat arch with voissoirs inclined to the same angle at each

side of the centre. The mortar joints do not, therefore, radiate to a common

centre. Not, technically, a proper arch, and of weak form.

SEMI CIRCULER OR ROMAN ARCH

• Semi-circular arch is very simple to construct or design as there is no

complex geometry or cutting of bricks. Its semicircular shape with all

the bricks facing towards the centre of the arch creates a wonderful

view. Two or three rows of bricks are layered to add decorative touch

to the beauty of the building.

BCT

SEMI CIRCULER OR ROMAN

ARCH

BCT

The main parts of an arch centre and

they define the curves are the ribs. They

are made up of the doubled up curved

section. The ties and the braces. These can

of course be made out of plywood or

rolled steel sections, but timber is still

commonly used.

The ribs are joined together by the

lagging and the plates.

The number of ribs used in the sketch

is only two, and so it is suitable for an

arch in a wall. However if more ribs are

added, along with more supports then it is

easy to see that a barrel vault could be

centered.

SEGMENTAL ARCH

BCT

The procedure is similar to that of the

semicircular arch, but as the curve is less

than a semicircle, the centre will lie

below the springing line

P

A

R

A

B arch

O

L

I

C

ARCH BCT

BCT

RELIVING

ARCHAn arch built over a lintel to relieve or

distribute the weight of the wall above

—called also discharging arch

BCT

TREFOIL

ARCH

BCT

MULTIFOIL

ARCH

BCT

OGEE

ARCH

BCT

BASKET HANDLE ARCHA three-centered arch that is somewhat flattened giving the effect of

a false ellipse.

CENTERED ARCH

BCT

One Center Arch

Segmental, semi circular, flat arches comes under this category.

Sometime , a perfectly circular arch known as bull’s eye arch ,provided for

circular window.

CENTERED ARCH

BCT

Two Center Arch

Pointed, semi-elliptical arches come under this category.

CENTERED ARCH

BCT

Three Center Arch

Elliptical arches come under this category.

An arch in which the intrados is a Combination of three arcs with one cantered between a symmetrically disposed pair.

O1

O2

O3

CENTERED ARCH

BCT

Four Center Arch

A four-centred arch, also known as a depressed arch or Tudor arch, is a low, wide type of arch with a pointed apex.It is much wider than its height and gives the visual effect of having been flattened under pressure. Venetian arch is typical example of this type.

Types of Arches on Geometry

Relieving Arch Different Types of Arches

BCT

Cont..

Relieving Arch Different Types of Arches

BCT

BCT

Cont..

BRICK ARCHES

*Rough brick arches

*Axed brick arches

*Gauged brick arches

STONE ARCHES

*Rubble arches

*Ashlar arches

GAUGED ARCHES

*Precast concrete block arches

*Monolithic concrete arches

39BCT

Types of Arches on Material of

Construction

Types of Arches on Material of Construction

Rubble Arch AshlarArch Monolithic Concrete Arch

R.C.C Arch Metal Arch Wooden Arch

BCT

Rough Brick Arches

These arches are built with ordinary

bricks, which are not in wedge

shape .

Also known as “RELIEVING

ARCHES”.

Made up of rectangular brick that

are not cut into wedge shape.

Curvature are obtained by mortar.

41BCT

Axed Brick Arches

Bricks are cut to wedge-shape.

Joints of arches are of uniform

thickness.

Not dress finely so it does not

give much attractive appearance.

42BCT

Gauged Brick Arches

Accurately prepared to wedge shape.

Specially shaped bricks known as “RUBBER BRICKS” are used

.

The lime putty is used for binding the blocks.

43BCT

Rubble Arches

Made of rubble stones, which are hammer dressed, roughly to the

shape and size of voussoirs of the arch and fixed in cement mortar.

These arches are used for small span upto 1 m.

44BCT

Ashlar Arches

Stones are cut to proper shape of

voussoirs and are fully dressed,

properly joint with cement or

lime.

The voussoirs made of full

thickness of the arch.

45BCT

Precast Concrete Block Arches

Used for small openings in

building.

The voussoirs, in the form

of cement concrete blocks

are prepared in special

moulds .

Generally , the concrete

blocks are used without

reinforcement.

46BCT

Monolithic Concrete Arches

Constructed from cast-in-situ

concrete ,either plain or

reinforced , depending upon

the span and magnitude of

loading.

Quit suitable for larger span

(3.0 m).

The curing is done 2 to 4

weeks.

47BCT

EVERY ELEMENT OF ARCH REMAINS IN

COMPRESSION.

An arches fail due to:-

1)Crushing of the masonry.

2)Sliding of voussoirs.

3)Rotation of some joints about an edge.

4)Uneven settlement of an abutment or pier.

48BCT

Crushing of The Masonry

If the compressive stress exceeds the safe crushing strength of

the masonry unit and mortar , the arch will fail in crushing.

The material should be of adequate strength and size of

voussoirs and should be properly designed to bear the thrust

transmitted through them.

49BCT

Sliding of Voussoirs

To safeguard against sliding of voussoirs past each other due to

transverse shear ,the voussoirs of greater height should be

provided.

Rotation of Some Joint About An Edge

Rotation can be prevented ,if the line of resistance is kept within

intrados and extrados.

Also, the line of thrust should be made to cross the joint away

from the edge to prevent the crushing of that edge.

50BCT

Uneven Settlement of An Abutment or Pier

Uneven settlement of abutment ,which causes secondary

stresses in arch.

Hence, the abutment which has ultimately to bear all the load

transferred to the arch , should be strong enough.

Also, the arch should be symmetrical , so that unequal

settlements of the two abutment is minimised.

51BCT

Uses of ArchArches with a circular form, also referred to as rounded arch, were commonly

employed by the builders of ancient history, heavy masonry arches.

Ancient Roman builders relied heavily on the rounded arch to span large, open

areas.

Several rounded arches placed in-line, end-to-end, form an arcade, such as the

Roman aqueduct.

Roman aqueduct near Nimes, France Horseshoe arches (9th century) in the Mosque of Uqba, in Kairouan, Tunisia

BCT

Uses of Arch Pointed arches were most often used by builders of Gothic-style architecture.

The advantage to using a pointed arch, rather than a circular arch, is that the

arch action in a pointed arch produces less thrust at the base.

This innovation allowed for taller and more closely spaced openings, typical of

Gothic architecture

Cathedral of St. Michael and St. Gudulain Brussels, Belgium, with its central,pointed arch window, typical of Gothicarchitecture.

BCT

Uses of Arch The parabolic arch employs the principle that when weight is uniformly applied

to an arch, the internal compression resulting from that weight will follow a

parabolic profile.

Of any arch type, the parabolic arch produces the most thrust at the base, but

can span the largest areas.

It is commonly used in bridge design, where long spans are needed.

BCT

Uses of Arch Vaults are essentially "adjacent arches are assembled side by side.“

If vaults intersect, complex forms are produced with the intersections.

The forms, along with the "strongly expressed ribs at the vault intersections,

were dominant architectural features of Gothic cathedrals."

Interior vaulted ceiling of Notre Dame de Paris, showing the ribs at the intersection

of several arches.

BCT

History of Arch

True arches, as opposed to corbel arches, were known by a number of

civilizations in the Ancient Near East, the Levant, and Mexico, but their use was

infrequent and mostly confined to underground structures such as drains where the

problem of lateral thrust is greatly diminished.

Arch of the Near East

Arch of Levant Mayan Corbel Arch

BCT

History of ArchA rare exception is the bronze age arched city gate of Ashkelon (modern day

Israel), dating to ca. 1850 B.C.

An early example of a voussoir arch appears in the Greek Rhodes Footbridge.

In 2010, a robot discovered a long arch-roofed passageway underneath the

Pyramid of Quetzalcoatl which stands in the ancient city of Teotihuacan north of

Mexico City, dated to around 200 AD

City gate of Ashkelon Greek Rhodes Footbridge

Arch-roofed passageway underneath the Pyramid of Quetzalcoatl

BCT

History of Arch The ancient Romans learned the arch from the Etruscans, refined it and were

the first builders to tap its full potential for above ground buildings.

Throughout the Roman empire, their engineers erected arch structures such as

bridges, aqueducts, and gates.

BCT

History of Arch They also introduced the triumphal arch as a military monument.

Vaults began to be used for roofing large interior spaces such as halls and

temples, a function which was also assumed by domed structures from the 1st

century BC onwards.

Arch of Constantine, Rome Arch of Triumph in Genoa, Italy

BCT

Examples of Arches

Muslim Arch Gothic Arch

Roman Arch Hindu Arch BCT

Why Arch is Important The arch is important because it is a marvelous way to structurally support the

mass of a building roof, a railway line, or an aqueduct, like the ones the Romans

built.

Some of the arches built by Ancient Romans still stand today, and they offer a

mute testament to the effectiveness of the arch in engineering.

The arch is still in wide use today, and we even see big glue-lams (wood glued

to laminate it to make large beams) in the shape of arches.

The arch has a long history in structures, man has built

BCT

Construction of Arches

BCT

Draw an elevation and a plan of a Pointed – Gothic Arch with a clear inner span of 1200 MM showing all its parts.

Draw a typical semicircular brick arch in an opening size of 1200 x 2100 MM. Consider a wall thickness of 230 MM and show plan and elevation indicating all the parts of an arch.


BCT

Critical Factors

1. Curing2. Quality of Bricks3. Providing arch - shaped door/window frames4. Quality of sand for mortar5. Availability of skilled masons

Tools Used

1. Trowels 4. Shovel2. Plumb bob 5. Baskets3. Thread


BCT

DO’SDON’T’S

1. Curing shall be done for seven days2. The mix should be of ratio 1:43. Mortar joints should V - shaped with

minimum thickness at bottom4. Mortar should be used within 30 minutes

of adding water to the mix5. Masonry should be always laid from both

sides upwards

1. Find sand should not be used for masonry2. Arch should not be disturbed while

removing the mould

Lintel and arch

Education

Transcript of Lintel and arch