Building Construction and Materials II Assistant Prof. Vinit Rajpurohit
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
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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.
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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.
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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
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Timber lintels
Easily available in hilly area.
Relatively costly, structurally weak and valnerable to fire.
Easily decay, if not properly taken care.
TIMBER LINTEL
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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
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Brick lintels
The brick are hard, well burnt , first class bricks .
Suitable for small span. The bricks having frogs
are more suitable.
BRICK LINTEL
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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.
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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
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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
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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
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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.
Different Types Of Arches:
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.
Different Types Of Arches:
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.
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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.
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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.
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SEMI CIRCULER OR ROMAN
ARCH
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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
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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
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RELIVING
ARCHAn arch built over a lintel to relieve or
distribute the weight of the wall above
—called also discharging arch
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TREFOIL
ARCH
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MULTIFOIL
ARCH
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OGEE
ARCH
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BASKET HANDLE ARCHA three-centered arch that is somewhat flattened giving the effect of
a false ellipse.
CENTERED ARCH
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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
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Two Center Arch
Pointed, semi-elliptical arches come under this category.
CENTERED ARCH
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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
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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
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Cont..
Relieving Arch Different Types of Arches
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Relieving Arch Different Types of Arches
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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
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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
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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
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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.
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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.
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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.
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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
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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
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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.
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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
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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
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Construction of Arches
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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.
Construction of Arches
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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
Construction of Arches
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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