BCM - Unit 2 - Pad
BCM - Unit 2 - Pad
BCM - Unit 2 - Pad
1
DEPARTMENT OF CIVIL ENGINEERING
IV-SEMESTER
Building Construction And
Elementary Building Drawing
UNIT NO.2
2
Brick Masonry and Stonework
Brick masonry
• Masonry is used to indicate the art of building structures
in either stones or bricks .
• The former type is called the stone masonry
• The latter type is called the brick masonry
Qualities of good bricks
• Brick should be of uniform in shape and should of standard
size of 19cmx9cmx9cm.
• Brick should give clear ringing sound when struck with
each other.
• Bricks when broken should show a bright homogenous and
compact structure free from voids.
• Bricks should have no cracks or flaws and fractured
surface should be free from holes, grit or lumps of lime etc.
• Brick should not absorb water more than 20 per cent by
weight for first class bricks and 22 per cent by weight for
second class bricks when soaked in cold water for a period
of 24 hours.
• Bricks should be sufficiently hard. No impression should
be left on brick surface when it is scratched with finger
nail.
• Brick should not break when dropped on flat hard ground
from a height of about one meter.
• Brick should have low thermal conductivity and it should
be sound proof.
• No bricks should have crushing strength below 55 kg/ cm
2.
• Toughness test
In this test when the bricks are dropped from a height of
90 to 120 cm on hard surface the brick should not be
break.
• Water absorption test
In this test when the bricks are immersed in cold water
for 24 hours and afterwards checked, the brick should
not absorb water more than 20 per cent of their weight
when dry.
Tests on bricks as per I.S. codes
• Compressive Strength
The sample of bricks shall be taken at random according to their
designation, numbers, lots and number of samples. The sample brick
shall be thoroughly wetted, the frog filled with CM (1:3) cured for 24
hours under wet gunny bags and 3 days under water; on removal from
water, the test sample shall be wiped dry. The test sample shall be
placed between plywood sheets of 3mm thick in such a way that frog
project upward and brick correctly center in the machine. The length,
breadth of each brick, shall be measured correct to one mm. The load
shall be applied at the rate of 140 kg/sq.m. per minute. The strength
shall be worked out in kg/sq.m. as follows :
Compressive strength in kg/ cm2 = Max. load at failure
Area of bricks
1) Stretcher
2) Header
3) Bond
4) Course
5) Header course
6) Stretcher course
7) Bed
8) Face
Technical terms used in masonry
9) Facing
10) Back
11) Backing
12) Hearting
13) Joint
14) Racking back
15) Perpend
16) Queen closer
Technical terms used in brick masonry
Technical terms used in brick masonry
Technical terms in brickwork
Beveled closer and mitered closer
Different bats
Plain and splayed jambs
Queen closer and king closer
Plain and splayed jambs
Weathering
Technical terms
Corbel
Thresholds
Bonds in brickwork
• All the joints should be properly flushed and filled with mortar
the no cavity is left in between.
• In case of two brick thick walls or having more thickness, the
joints should be grouted at every course in addition to
bedding and flushing with mortar.
• No brick bats should be used I the work excepts when it is
absolutely necessary for obtaining the specified bond.
• Brick work is generally laid in English bond. In all cases it
should be ensured that the proper bond should be
maintained throughout the work.
PRINCIPLES OF CONSTRUCTION
• Only specified quality of motor should be used in the
brickwork and great care should be taken to ensure that
uniform mortar joints is obtained in the construction.
Thickness of joint should not exceed 13mm in any case.
• Unless brick on edge is specified, the bricks must be laid on
their proper beds with their frogs pointing upwards.
• The courses of bricks at the plinth, window sill, floor roof
level and at the top of parapet wall should be invariably laid
with brick on edge.
• The progress of work in raising masonry should be carried
up in uniform layers at one level. It should be ensured that
no part of the wall should preferably be rise more than 100
cm. The walls should be raised truly vertical.
PRINCIPLES OF CONSTRUCTION
• The buttresses, counter forts etc should be built up
course by course maintaining proper bond with the
main wall and should not be added or joggled
afterwards.
• Iron fixtures like pipes, hold pasts of doors and
windows etc. which are to be fixed in the brick wall
should be embedded in cement mortar or cement
concrete.
• The face joints are generally raked to a minimum depth
of 10 to 15 mm, when the mortar in the joints is still
green. This is required to be done to provide proper key
for the plastering and pointing.
PRINCIPLES OF CONSTRUCTION
• Plastering should be done after about 28 days of
completion of brick masonry. This permits adequate
time for the shrinkage of masonry.
• In works where plastering and pointing is not desired,
the mortar joints should be struck, flush and finished at
the time of lying.
• All the finished masonry work should be kept wet for at
least seven days.
• When it is desired to increase e the length of the wall
under construction at a future date the wall is stopped
with a toothed end. This is necessary to ensure
continuous bonding between the old and the new work.
PRINCIPLES OF CONSTRUCTION
• It is found that with an average winter summer temperature
differences of about 1000 F, a brick masonry wall expands
by about 10mm in every 30m length of wall. Hence it is
desirable to provide minimum of 18mm wide expansion
joints after every 30 to 45 m length of wall.
• When timber floor or roof is required to be supported on
masonry walls the ends of the timber joists (supporting the
floor or roof) should rest on corbels or brackets as far as
possible. In cases where the ends of Tiber joists have to be
built in to the wall itself, it is necessary to apply suitable
preservative treatment to the embedded portion of the
joists and in addition some space should be left around
them to minimize chances of attack by termite and to
ensure free circulation of air
PRINCIPLES OF CONSTRUCTION
• The bearing of R.C.C. floor or roof slab resting on brick
masonry walls should not be less than the effective depth
of the slab or 10 cm whichever is more.
• As a general practice, quoin brick should be headers and
stretchers laid in alternate courses and bond is developed
by placing a quoin closer next to the queen header.
• Half brick partition wall should be reinforced with suitable
reinforcement placed at every third or fourth course of the
brick work. The reinforcement may be in the form of mild
steel bars, flat bar hoops, iron, expanded mesh or steel
fabric etc.
PARAPETS
• It is a low wall built around a flat roof to act as a
protective solid balustrade for the users of the terrace
(flat roof). In pitched roof parapet wall is provided to
conceal the gutter at caves level and for imparting an
architectural effect to the structure.
COPING
• Coping is a covering placed on the exposed top of an
external wall. It is essentially provided to prevent the
seepage of water through the joints of the topmost
courses of the wall. It may be of concrete, stone, brick or
terra-cotta.
SILLS
• It is a horizontal member of brick, stone, concrete, or
wood provided to give support for the vertical members
of a window. It is also employed for the purpose of
shedding off rain water from the face of wall immediately
below the window opening.
CORBEL
1 Stone Masonry
Common building stones in India
Sr. Stone Classificatio Qualities Uses Localities
No. n
1 Basalt Igneous Hard and tough, difficult to work, its sp. Gr. Is 3 Road metal, for Maharashtra, Bihar,
and trap and compressive strength varies from 150 to rubble masonry, Gujrat,
185 N/mm2. Its weight varies from 18 to 29 foundation work etc. Bengal and M.P.
KN/m3.
2 Chalk Sedimentary Pure white limestone; soft and easy to form In preparing glazier’s Maharashtra,
powder. putty; as coloring Rajasthan, Punjab,
material in Gujrat, Andaman,
manufacture of iIands, Bengal , Bihar
Portland cement A.P. Himachal
Pradesh , M.P. & U.P.
3 Gneiss Metamorphic Splits in to thin slabs; easy to work, Its sp. Gr. Is Street paving, rough Madras, Mysore ,
2.69 and compressive strength is 206N/mm2 stone masonry work Bihar, A.P.
etc. Maharashtra, Bengal,
Kerala , and Gujrat.
4 Granite Igneous Hard, durable and available in different colors, Steps, sills, facing Kashmir, Madras,
highly resistant to natural forces , can take nice work, walls , bridge Mysore , Punjab
polish, Its sp. gr. Varies from 2.6 to2.7 piers, columns, road Bihar, U.P. M.P.
compressive strength varies from 75 to 127 metal, ballast etc. It is Maharashtra, Bengal,
N/mm2. Its weight is about 26 to 27 KN/m3. unsuitable for carving Kerala , and Gujrat.
Assam
Sr. Stone Classification Qualities Uses Localities
No
.
5 Kankar Sedimentary Impure limestone Road metal, North and central
manufacture India
of hydraulic
lime etc.
6 Laterite Metamorphic Porous and spongy structure, easily Building stone Bihar, Orissa , Mysore,
quarried in blocks, contain high , road metal M.P. Maharashtra,
percentage of oxide of iron; available in rough stone Kerala , A.P. and
different colors. Its compressive masonry work Madras.
strength varies from 1.8 to 3.1 N/mm2. etc.
7 Limestone Sedimentary Consist of carbonate of lime, easy to Floors, steps, Maharashtra,
work, Its sp. gr. varies from 2.00 to 2.75 walls, road Rajasthan, Punjab,
and compressive strength is 54N/mm2. metal Gujarat, Andaman,
,manufacture Islands, Bengal, Bihar,
of lime in blast A.P. Himachal Pradesh,
furnaces.etc. M.P. and U.P.
8 Marble Metamorphic Can take good polish and available in Flooring Rajasthan,
different colors. Its sp.gr. Is 2.65 and facing work, Maharashtra, Gujarat,
compressive strength is 71 N/mm2 columns, A.P., Mysore, M.P. and
steps, U.P.
ornamental
work etc.
Sr. Stone Classificati Qualities Uses Localities
No. on
9 Murum Metamorphic Decomposed laterite, deep brown Blindage for Same as laterite
or red in color. metal roads , for
fancy path and
garden walls
10 Quartzite Metamorphic Hard brittle crystalline and compact, Retaining walls, Bengal, A.P. Himachal
difficult to work and dress. road metal, Pradesh, Madras, U.P.
concrete Mysore , Gujarat, Punjab
aggregate and Rajasthan
pitching, rubble
masonry , facing
of buildings etc.
11 Sandston Sedimentary Consists of quartz and other Steps facing A.P. M.P. Punjab,
e minerals, easy to work and dress, work, columns, Rajasthan, Maharashtra,
and available In different colors, Its flooring walls , Gujarat, Andaman islands
sp. gr. Varies form 2.65 to 2.95and road metal , Bengal, Bihar, Himachal
compressive strength is 64 N/mm2 ornamental Pradesh, Kashmir, Madras
Its weight is about 20to 22kn/m3. carving etc. and U.P.
12 Slate Metamorphic Black colur and splits along natural Roofing work, U.P. M.P. Bihar Madras,
beddign planes non absorbant Its sp. sills , damp proof Rajasthan, and Mysore.
gr. Is 2.89 and compressive strength courses , etc.
varies from 75 to 207 N/mm2.
Cutting and dressing of stones
• Planning: In this process stones are cleared off from all the
irregularities from the surface
2. Hardness
3. Durability
4. Resistance to fire
5. Bio-Deterioration
6. Appearance