Building components and structures

1. UNIT III
BUILDING COMPONENTS AND
STRUCTURES
Foundations: Types of foundations - Bearing capacitSy and settlement –
Requirement of good foundations.
Civil Engineering Structures: Brickmasonry – stonemasonry – beams – columns –
lintels – roofing– flooring – plastering – floor area, carpet area and floor space
index - Types of Bridges and Dams –water supply - sources and quality of water -
Rain water harvesting - introduction to high way and rail
way.

2. Foundation
• Foundation is the lowest part of the building or the civil structure that is in direct contact with the soil
which transfers loads from the structure to the soil safely.
• Generally, the foundation can be classified into two, namely shallow foundation and deep foundation.
• A shallow foundation transfers the load to a stratum present in a shallow depth. The deep foundation
transfers the load to a deeper depth below the ground surface

3. Purpose of foundation
• Foundation are the main reason behind the stability of any structure. The
stronger is the foundation, more stable is the structure.
• The proper design and construction of foundations provide a proper surface for
the development of the substructure in a proper level and over a firm bed.
• Specially designed foundation helps in avoiding the lateral movements of the
supporting material.
• A proper foundation distributes load on to the surface of the bed uniformly. This
uniform transfer helps in avoiding unequal settlement of the building. Differential
settlement is an undesirable building effect.
• The foundation serves the purpose of completely distributing the load from the
structure over a large base area and then to the soil underneath. This load
transferred to the soil should be within the allowable bearing capacity of the soil.

4. Types of foundation
1.Shallow foundation
The depth of the foundation is less than the
width of the foundation.
a. Individual footing or isolated footing
b. Combined footing
c. Strip foundation
d. Raft or mat foundation
2.Deep Foundation
When the depth of the foundation is
greater than 3m.
a. Pile foundation
b. Drilled Shafts or caissons

5. 1.Shallow foundation
2. Combined footing
• It is constructed when two or more
columns are close enough and their
isolated footings overlap each other.
• combination of isolated footings, but
their structural design differs.
• Rectangle
• used when loads from the structure is
carried by the columns.
3. Strip foundation
• base is wider than a typical
load-bearing wall
foundations.
• used for individual columns,
walls and bridge piers where
the bearing soil layer is within
3m (10 feet) from the ground
surface.
• Soil bearing capacity must be
sufficient to support the
weight of the structure over
the base area of the structure
4. Raft or Mat Foundations
• which are spread across the
entire area of the building to
support heavy structural loads
from columns and walls.
• Used where the loads from the
structure on columns and walls
are very high.
• prevent differential settlement of
individual footings
• suitable for expansive soils

6. 2.Deep Foundation
1.Pile foundation
• used to transfer heavy
loads from the
structure to a hard rock
strata.
• resists the loads from
the structure by skin
friction and by end
bearing.
• prevents differential
settlement of
foundations.
2. Drilled Shafts or Caisson Foundation
• has an action similar to pile foundations discussed above, but
are high capacity cast-in-situ foundations.
• It resists loads from structure through shaft resistance, toe
resistance and/or combination of both of these.
• transfer column loads larger than pile foundations.
• It is used where the depth of hard strata below ground level is
located within 10m to 100m (25 feet to 300 feet).
• not suitable when deep deposits of soft clays and loose, water-
bearing granular soils exist.
• It is also not suitable for soils where caving formations are
difficult to stabilize, soils made up of boulders, artesian aquifer
exists.

7. Bearing capacity
• bearing capacity is the capacity of soil to support the loads applied to the
ground.
• The bearing capacity of soil is the maximum average
contact pressure between the foundation and the soil which should not
produce shear failure in the soil.
• Ultimate bearing capacity is the theoretical maximum pressure which can
be supported without failure;
• allowable bearing capacity is the ultimate bearing capacity divided by
a factor of safety.
• There are three modes of failure that limit bearing capacity: general shear
failure, local shear failure, and punching shear failure.
• It depends upon the shear strength of soil as well as shape, size, depth and
type of foundation.

8. settlement
• soils deform under the load of foundation structures.
• The total vertical displacement that occur at foundation level is
termed as settlement.
• The cause of foundation settlement is the reduction of volume air
void ratio in the soil.
• the magnitude of foundation settlement is controlled by many factors
type of soil and foundation structure.
• Foundations on bedrock settle a negligible amount.
• In contrary, Foundations in other types of soil such as clay may settle
much more.

9. settlement
• building foundation settlement is normally limited to amounts measured in
millimeter or fractions of an inch.
• Structures will suffer damages due to settlement of its foundation
specifically when the settlement occur in quick manner.
• Types :
1. Differential foundation settlement
2. Uniform foundation settlement

10. Differential foundation settlement
• Settlement that occurs at differing rates between different portions of a building is termed
differential settlement.
• Differential settlement occurs if there is difference in soils, loads, or structural systems between
parts of a building. in this case, different parts of the building structure could settle by
substantially different amounts.

11. Differential foundation settlement
• the frame of the building may become distorted, floors may slope, walls
and glass may crack, and doors and windows may not work properly.
• Uneven foundation settlement may force buildings to shift out of plumb
which lead to crack initiation in foundation, structure, or finish.
• Majority of foundation failures are attributable to severe differential
settlement.
• Lastly, for conventional buildings with isolated foundations, 20mm
differential settlement is acceptable. And 50mm total settlement is
tolerable for the same structures.

12. Uniform foundation settlement
• Similarly, when loads on the building and the design of its structural system are uniform
throughout, the anticipated settlement would be uniform type.
• Commonly, uniform settlement has small detrimental influence on the building safety.
• However, it influences utility of the building for example damaging sewer; water supply; and
mains and jamming doors and windows.
• when foundation settlement occurs at nealy the same
rate throughout all portions of a building, it is called
uniform settlement.
• If all parts of a building rest on the same kind of soil,
then uniform settlement the most probable type to take
place.

14. Foundation settlement causes
• Direct causes
• The direct cause of foundation settlement is the weight of building
including dead load and live load.
• Indirect causes
• Failure of collapsible soil underground infiltration
• Yielding of excavation done adjacent to foundation
• Failure of underground tunnels and mines
• Collapse of cavities of limestones
• Undermining of foundation while flood
• Earthquake induced settlement
• Finally, due to extraction of ground water and oil.

15. Components of total settlement of foundations
1.Immediate settlement
• It is also called short term
settlement.
• Immediate settlement take
place mostly in coarse grained
soils of high permeability and in
unsaturated fine-grained soils
of low permeability.
• Lastly, it occurs over short
period of time which about 7
days. So, it ends during
construction time.
2.Primary settlement
• It also termed as primary
consolidation
• Take place over long period of
time that ranges from 1 to 5
years or more
• Primary settlement frequently
occurs in saturated inorganic
fine grain soil.
• Expulsion of water from pores
of saturated fine grain soil is
the cause of primary
settlement.
3.Secondary settlement
• Secondary settlement is the
consolidation of soil under
constant effective stress.
• Frequently, it occurs in
organic fine grain soil.
• It continues over the life
span of foundation
structure similar to creep in
concrete.

16. Requirements of a Good Foundation
1. The foundations shall be constructed to sustain the dead and imposed loads and
to transmit these to the sub-soil in such a way that pressure on it will not cause
settlement which would impair the stability of the building or adjoining structures.
2. Foundation base should be rigid so that differential settlements are minimised,
specially for the case when super-imposed loads are not evenly distributed.
3. Faundations should be taken suficiently deep to guard the building against
damage or distress caused by swelling or shrinkage of the sub-soil.
4. Foundations should be so located that its performaced may not be affected due
to any unexpected future influence.

17. BRICK MASONRY
• Brick masonry is built with bricks bonded together with mortar. For temporary sheds mud mortar
may be used but for all permanent buildings lime or cement mortars are used.
• The various types of bonds generally used in brick masonry are
1. Stretcher bond
2. Header bond
3. English bond and
4. Flemish bond.

18. Stretcher Bond
• longer face of the brick as seen in the elevation.
• In the brick of size 190 mm × 90 mm × 90 mm, 190 mm × 90 mm face is the
stretcher.
• In stretcher bond masonry all the bricks are arranged in stretcher courses
• care should be taken to break vertical joints.
• This type of construction is useful for the construction half brick thick partition wall.

19. Header Bond
• A header is the shorter face of the brick as seen in the elevation.
• In a standard brick it is 90 mm × 90 mm face.
• In header bond brick masonry all the bricks are arranged in the header
courses.
• This type of bond is useful for the construction of one brick thick wall.

20. English Bond
• consist of headers and stretchers.
• considered to be the strongest bond.
• Hence it is commonly used bond for the walls of all thicknesses.
• To break continuity of vertical joints a brick is cut lengthwise into two
halves and used in the beginning and end of a wall after first header.
• This is called queen closer..

21. Flemish Bond
• In this type of bond each course comprises of alternate header and stretcher.
• Alternate courses start with stretcher and header.
• To break the vertical joints queen closers are required, if a course starts with header.
• Every header is centrally supported on the stretcher below it.
• Flemish bonds may be further classified as
(a) Double Flemish Bond
In case of double flemish bond, both
faces of the wall have flemish look,
i.e. each course consist of alternate
header and stretcher, whereas
(b)single flemish bond
outer faces of walls have flemish look
whereas inner faces have look of English
bond

22. Advantages:
1. Since shape and size of bricks are uniform, it do not need skilled labour for the
construction.
2. Bricks are light in weight and hence handling them is easy.
3.Bricks are easily available around cities and their transportation cost is less because their
weight is less. Stones are to be brought from quarries which are located only at few places.
4.It is possible to use all types of mortar in brick masonry. For unimportant buildings even
mud mortar can be used.
5. Thinner walls can be constructed with bricks but it is not so with stones.
6. It is easy to form openings for doors and windows.
7. Dead load of brick masonry is less.
8. In brick masonry mortar joints are thin and hence construction cost is reduced
considerably.
9. Brick masonry has better fire and weather resistance compared to stone masonry.

23. Disadvantages
1. Strength of brick masonry is less than that of stone masonry.
2. Durability of brick masonry is less.
3. Brick masonry needs plastering and plastered surface needs colour washing.
Stone masonry don’t need them and hence maintenance cost is more in brick
masonry.
4. Brick masonry absorbs water and there are possibility of dampness. There is no
such problem in stone masonry.
5. More architectural effects can be given in stone masonry compared to that in
brick masonry.
6. Stone masonry gives massive appearance and hence monumental buildings are
built in stone masonry.

24. Stone masonry
• Masonry means construction of buildings using building blocks like
stone, bricks, concrete blocks etc.
• Masonry is used for the construction of foundation, plinth, walls and
columns.
• Mortar is the binding material for the building blocks.
• 2 types: Rubble masonry, Ashler masonry

25. Rubble Masonry
• stones of irregular sizes and shapes are used.
• To remove sharp shapes they may be hammered.
• The rubble masonry may be coursed or uncoursed
• In uncoursed rubble masonry the wall is brought to
level at every 300 mm to 500 mm.
• The mortar consumed in these construction is more.
• Course rubble masonry is used for the construction of
Public and residential buildings.
• Uncoursed rubble masonry is used for the construction
of foundations, compound walls, garages, etc.
• A skilled mason may arrange the facing stones in
Polygonal shapes to improve the aesthetic of the wall.

26. Ashlar Masonry
• stones are dressed to get suitable shapes and sizes.
• The height of the stones varies from 250 mm to 300 mm. The length should not
exceed three times the height.
• The dressing of the stone need not be very accurate on all sides.
• Usually good dressing is made on facing side.
• In such construction mortar consumption is less compared to rubble masonry.

27. Types of ashler masonry
1. Ashler fine masonry
• The beds, sides and faces
are finely chisel dressed
• Mortar joints does ot
exceed 3 mm
• Smooth appearance
• Costly in construction
2.Ashler rough tooled masonry
• The beds and sides are finely
chisel dressed
• The strip is about 25mm wide
3.Ashler rock faced masonry
• A strip of 25mm wide is made by
chisel around the perimeter.
• The remaining portion is left as the
same form
4. Ashler chamfered masonry
• The stripis provided above
• Chamfered at 45° angle by chiesel.
• Depth is 25mm
5.Ashler block in course masonry
• Stones are hammer dressed
• Used in heavy engineering works

28. Beam
• Beams are defined as horizontal load carrying member in a structure.
• The total effect of all the forces acting on the beam is to produce shear
forces and bending moments within the beams, that in turn induce internal
stresses, strains and deflections of the beam. Beams are characterized by
their manner of support, profile (shape of cross-section), equilibrium
conditions, length, and their material.
• Reinforced cement concrete, concrete, pre-stressed concrete and steel I
sections are used as beams to support the slabs.

29. Classification -based on support
1.Simply supported – beams supported on the
ends which are free to rotate and have no
moment resistance.
pinned beam
2.Fixed – beams supported on both ends
and restrained from rotation.
3.Over hanging – simple beams extending beyond
its support on one end

30. Classification -based on support
4.Double overhanging – simple beams with
both ends extending beyond its supports
on both ends.
5. Continuous – beams extending over more
than two supports.
6. Cantilever – a projecting beam fixed only at one
end.

31. Classification based on profile
The kind and magnitude of internal stress
generated in the beam is directly dependent
on the shape of the cross-section, thus
requiring classification based on profile.
1.Rectangular Beams
2.I-Beams
3.T-Beams
4.C-Beams
5.Other Cross-sections
Classification based on geometry
1.Straight Beams
2.Curved Beams
3.Tapered Beams
Classification based on indeterminacy
1.Statically determinate beams:
equilibrium conditions sufficient to
compute reactions.e.g. simply supported
beams, cantilever beams, single and
double overhanging beams etc.
2.Statically indeterminate beams:
Deflections (Compatibility conditions)
along with equilibrium equations should be
used to find out reactions.e.g. propped
cantilever, continuous beams, fixed beams.
Classification based on material
1.Concrete Beams
2.Steel Beams
3.Timber Beams

32. COLUMN
• The vertical load carrying member of a structure is called column.
• They are constructed of timber, stone, reinforced cement concrete of steel
section.
• Classified: 1. Long column 2. Short column
Long column
The ratio of effective length to least lateral
dimension is less than 12 called as long
column
Short column
The ratio of effective length to least lateral
dimension is more than 12 called as long
column

33. Reinforced cement concrete column
• Usually the reinforced cement concrete column are cast in-situ type.
• They may be constructed in square, rectangular, circular shapes.
• Vertical reinforcements or main reinforcements are provided to take up
major load coming over the column.
• Generally the diameter of vertical reinforcement may vary from 10mm to
40mm.
• Longitudinal reinforcement bars should not be less than 0.8% and not more
than 6% of the cross sectional area of the column. The diameter of lateral
reinforcement may vary from 6mm to 10mm.
• In the multi storyed buildings, the section of the column in upper stories may
be reduced as they have to carry lesser loads. But the centre lines of various
columns of different stories must coincide in a same vertical line.

35. Steel columns
• Struts of one or two angles are used as compression member in roof trusses.
• Latticed columns made up of channels or angles connected by lattice bars
are often used where light loads are to be supported on long columns.
• battened columns made up of channels or angles connected only batten plate
are also used as column.
• Rolled H-columns which are available in depths ranging from 150 mm to 500
mm and are now commonly used in steel Skelton construction.

37. Lintels
• A lintel is a horizontal member which is placed across the openings.
• Openings are invariably left in the wall for the provision of doors, windows
etc.
• A lintel is thus a sort of beam, the width of which is equal to the width of
which is equal to the width of the wall, and the ends of which are built into
the wall.

38. Classification of Lintels
• Timber lintels
• Stone lintels
• Brick lintels
• Steel lintels
• Reinforced cement
concrete lintels

39. Classification of Lintels
Timber lintels
• the oldest types of lintels, though
they are not commonly used now-
a-days, except in hilly areas.
• The sound and hard .
• As the timber is easily liable to
catch fire, only good quality is
constructed over coat of suitable
preservative should be used as
lintels.
Stone lintels
• used in stone masonry
structures.
• This consists of a simple
stone slab of greater
thickness.
• Stone lintels can also be
provided over openings in
brick walls.
Brick lintels
• not structurally strong and they are
used for small openings, generally
not exceeding not exceeding 1 meter
span, and light loads.
• They are built up with hand well
burnt, copper colored, free from
cracks and with sharp and straight
edged bricks.
Steel lintels
• Steel lintels are provided where the opening
is large and the super imposed loads are also
heavy.
• It consists of rolled steel joists or channel
sections.
Reinforced cement concrete lintels
• have replaced practically all other types of lintels because of
their strength, rigidity, fire resistance economy and case in
construction
• width equal to the width of the wall.
• The depth of R.C.C lintel and the reinforced depends upon the
span and magnitude of loading.
• It can be pre-cast ot cast-in-situ, pre-cast R.C.C lintels are
preferred for small spans upto about 2 meters.

40. Roof
• Roof is the upper most portion of the building which protects the building
from rain, wind and sun.
• Various types of roofs used may be divided broadly into three types:
1. Flat roofs
2. Pitched roofs
3. Shells and folded plates.

41. 1. Flat Roofs
• nearly flat.
• slight slope (not more than 10°) is given to drain out the rain water.
• All types of upper storey floors can serve as flat roofs.
• Many times top of these roofs are treated with water proofing
materials-like mixing water proofing chemicals in concrete, providing
coba concrete.
• with advent of reliable water proofing techniques such roofs are
constructed even in areas with heavy rain fall.

42. Advantages &Disadvantages
The advantages of flat roofs are:
(a) The roof can be used as a terrace for playing
and celebrating functions.
(b) At any latter stage the roof can be converted
as a floor by adding another storey.
(c) They can suit to any shape of the building.
(d) Over-head water tanks and other services can
be located easily.
(e) They can be made fire proof easily compared
to pitched roof.
The disadvantages of flat roofs are:
(a) They cannot cover large column free areas.
(b) Leakage problem may occur at latter date also
due to development of cracks. Once leakage
problem starts, it needs costly treatments.
(c) The dead weight of flat roofs is more.
(d) In places of snow fall flat roofs are to be avoided
to reduce snow load.
(e) The initial cost of construction is more.
(f) Speed of construction of flat roofs is less.

43. Pitched Roofs
• In the areas of heavy rain falls and snow fall sloping roof are used.
• The slope of roof shall be more than 10°. They may have slopes as much as
45° to 60° also.
• The sloped roofs are known as pitched roofs.
• The sloping roofs are preferred in large spanned structures like workshops,
factory buildings and ware houses.
• In all these roofs covering sheets like A.C. sheet, G.I. sheets, tiles, slates etc.
are supported on suitable structures.
• The pitched roofs are classified into
(a) Single roofs (b) Double or purlin roofs (c) Trussed roofs.

44. Single Roof
• If the span of roof is less than 5 m
the following types of single roofs
are used.
• (i) Lean to roofs (ii) Coupled roofs
(iii) Coupled-close roof (iv) Collar
beam roof
• In all these roofs rafters placed at
600 mm to 800 mm spacing are
main members taking load of the
roof.
• Battens run over the rafters to
support tiles.

45. Double or Purlin Roofs
• If span exceeds, the cost of
rafters increase and single
roof becomes uneconomical.
• For spans more than 5 m double
purlin roofs are preferred.
• The intermediate support is
given to rafters by purlins
supported over collar beams.

46. Trussed Roof
• If span is more, a frame work of slender members are used to
support sloping roofs.
• These frames are known as trusses.
• A number of trusses may be placed lengthwise to get wall free longer halls.
Purlins are provided over the trusses which in turn support roof sheets.
• For spans up to 9 m wooden trusses may be used but for larger spans steel
trusses are a must

47. Shells and Folded Plate Roofs
• Shell roof may be defined as a curved surface, the thickness of which is small
compared to the other dimensions
• In these roofs lot of load is transferred by membrane compression instead of
by bending as in the case of conventional slab and beam constructions.
• Caves are having natural shell roofs.
• However the shells of middle ages were massive masonry structures but
nowadays thin R.C.C. shell roofs are built to cover large column free areas

49. Advantages and Disadvantages of Shell Roofs
Advantages
(a) Good from aesthetic
point of view
(b) Material consumption is
quite less
(c) Form work can be
removed early
d) Large column free areas
can be covered.
Disadvantages
(a) Top surface is curved and
hence advantage of terrace is
lost.
(b) Form work is costly.

50. Folded plate roofs
• may be looked as slab with a number of folds.
• These roofs are also known as hipped plates, prismatic shells and faltwerke.
• In these structures also bending is reduced and lot of load gets transferred as
membrane compression.
• However folded plates are not so efficient as shells.

52. Advantages and Disadvantages of Folded Plate Roofs
Advantages
(a) Form work required is relatively
simpler.
(b) Movable form work can be
employed.
(c) Design involves simpler
calculations.
Disadvantages
(a) Folded plate consume more
material than shells.
(a) Form work can be removed after
7 days while in case of shells it can
be little earlier.

53. Roof Coverings for Pitched Roofs
• Various types of covering materials are available for pitched roofs and their selection depends upon
the climatic conditions, fabrication facility, availability of materials and affordability of the owner.
• Commonly used pitched roof covering materials are:
(a) Thatch
(b) Shingle
(c) Tiles
(d) Slates
(e) Asbestos cement (A.C.) sheets
( f ) Galvanised iron (G.I.) sheets

54. Flooring
• Purpose of flooring is to get a good hard, level and beautiful surface for
living.
• The floors directly resting on the ground are known as ground floors while
the floors of each storey are known as upper floors.
Ground Floor
• Apart from giving good finished surface, these floors should have good damp
resistance.
• The ground surface is rammed well and a layer of red earth or sand is placed
which is compacted
• . A layer of broken bricks, stones etc. is provided up to 150 mm below floor
finish level and rammed.
• While ramming the surface is kept moist to get good compaction.
• Then 1 : 4 : 8 concrete of 100 to 150 mm thickness is provided as base
course. Over this bed floor finish is laid.

55. types of flooring
1. Mud and Moorum
• These floorings are used in low cost
housing, specially in villages.
• Over the hard layer of earth filling
mud or moorum layer is provided.
The floor needs a thin wash of cow
dung at least once a weak.
2. Brick Flooring:
• cheap floor construction.
• commonly used in godowns and
factories.
• Bricks are laid flat or on edges.
Bricks of good quality used
• Brick layer is provided on sand
bed or on lean concrete (1 : 8 :
16) bed.
3.Flag Stone Flooring:
• Laminated sand stones or slates of 20
mm to 40 mm thick in the form of slabs
of 300 mm × 300 mm or 450 mm × 450
mm or in the form of rectangles of size
450 mm × 600 mm are used as floor
finishes.
• laid on 20 to 25 mm thick mortar spread
over concrete bed.
• The joints are to be finished with rich
mortar.
4. Cement Concrete Floors
• cheap and durable floor
• It consists of two courses-base course
and wearing coat.
• Base course is laid over well
compacted soil. Its thickness is usually
75 mm to 100 mm.
5. Terrazo Flooring:
• applied over concrete flooring to get pleasing appearance.
• consists of 75 to 80% of surface marble chips embedded in
cement mortar.
• Marble chips are mixed in cement in the proportion 1 : 1.25 to
1 : 2 and about 6 mm terrazo topping is laid. The top is tamped
and rolled.
• Additional marble chips are spread during tamping to get
proper distribution of marble chips on the surface. After drying
it for 12 to 20 hours, it is cured for 2–3 days.

56. types of flooring
6. Mosaic Flooring:
• finishing coat of small pieces of
broken tiles of China glazed or
of marble arranged.
• The base coarse is concrete
flooring and on it 30 to 40 mm
mortar layer is provided.
• After 20 to 24 hours of drying
the top is rubbed with
carborundum stone to get
smooth and polished surface.
7.Marble Flooring:
• Marble slabs are cut to get
marble tiles of 20 to 25 mm
thickness.
• With power driven machine
surface is polished to get
even and shining surface.
8. Tiled Flooring:
• Tiles of clay, cement or terrazo of standard sizes
are manufactured in factories under controlled
conditions.
• On the concrete base, 25 mm to30 mm thick
mortar is laid and these tiles are placed and
pressed with trowel or woodenmallet.
• Then that is filled with coloured cement slurry to
get uniform colour on the top surface. After curing
for 7 days grinding and polishing is made as in the
case of terrazo flooring.
9. Timber Flooring:
• used in dancing halls and in
auditoriums.
• Timber plates may be directly
placed on concrete bed or may
be provided over timber frame
work.
• In latter case it is necessary to
provide proper ventilation below
the floor. This flooring is costly.
10.P.V.C. Flooring:
• plastic which is available in
different colour and shade.
• Adhesives are applied on
concrete base as well as on
bottom of PVC tiles.
• tile is pressed gently with 5
kg wooden roller
• The oozed out adhesive is
wiped
• The floor finish is smooth,
attractive and can be easily
cleaned.
11.Rubber Flooring:
• Tiles or sheets of rubber with fillers such as
cotton fibres, asbestos fibre or granulated cork
are manufactured
• These sheets or tiles may be fixed to concrete or
timber floors.
• These floors are attractive and noise proof.
However they are costly.

57. Plastering
• Applying mortar coats on the surfaces of walls, columns, ceiling etc. to get
smooth finish is termed as plastering.
• Mortar used for plastering may be lime mortar, cement mortar or lime-cement
mortar.
• Lime mortar used shall have fat lime to sand ratio of 1 : 3 or 1 : 4.
• If hydraulic lime is used mix proportion (lime: sand) is 1 : 2.
• Cement mortar of 1 : 4 or 1 : 6 mix is very commonly used for plastering, richer
mix being used for outer walls. T
• o combine the cost effectiveness of lime mortar and good quality of cement
mortar many use lime-cement mortar of proportion (cement : lime : sand) of 1
: 1 : 6 or 1 : 1 : 8 or 1 : 2 : 8.

58. objective & Requirements
The objective of plastering are:
1. to conceal defective workmanship
2.to give smooth surface to avoid catching
of dust.
3. to give good look.
4. to protect the wall from rain water and
other atmospheric agencies.
5. to protect surfaces against vermit.
Requirement of good plaster are:
1. It should adhere to the background
easily.
2. It should be hard and durable.
3. It should prevent penetration by
moisture
4. It should be cheap.

59. Plastering
• L ime mortar : 3 coats , cement mortar - 2 or 3 coats for the stone and brick
masonry. For concrete surfaces cement mortar 2 or 3 coats. For concrete
building blocks -one coat of cement mortar .
• The first coat provides means of getting level surface. The final coat provides
smooth surface. If three coats are used second coat is known as floating coat.
• The average thickness of first coat is 10 to15 mm. Middle coat thickness is 6–
8 mm. The final coat is just 2 to 3 mm thick. If single coat is used its thickness
is kept between 6 to 12 mm. Such coats are used on concrete surfaces not
exposed to rain.

60. FLOOR AREA
• A floor area of a building or buildings is the sum of the gross horizontal
areas of the several floors of all buildings on the lot, measured from the
exterior faces of exterior walls, or from the center line of walls separating
two buildings.
• Floor area shall include the area of basements when used for residential,
commercial, or industrial purposes, but need not include a basement or
portion of a basement used for storage or the housing of mechanical or
central heating equipment, or the basement apartment of a custodian in a
multifamily dwelling, except that portion of said custodian's dwelling unit
which is in excess of 50 per cent of the total basement floor area.

61. calculating floor area
• Attic space providing structural head room of less than 7 feet, 6 inches;
• Uncovered steps;
• Terraces, breezeways and open porches;
• Automobile parking space in a basement or private garage, but not to
exceed 600 square feet for single-family dwelling, 800 square feet for a two-
family dwelling, and 200 square feet per car space required by the
provisions of this ordinance for any other use;
• Accessory off-street loading berths, but not to exceed twice the space
required by the provisions of this ordinance.

62. Floor area ratio
• Floor area ratio. The floor area of the building or buildings on a zoning
lot, divided by the area of that zoning lot.

63. Carpet area
• Carpet area is the area that can be used to spread a carpet inside the house.
• It is the net usable area of the apartment.
• It includes the thickness of the internal wall but excludes balcony or terrace.
• Technically, the distance between inner walls is carpet area. Also, it will
include staircase only if it is inside the apartment, but balcony, lift, lobby,
etc. will not include in carpet area.
• carpet area is 70 per cent of built-up area.
• Carpet area + wall area = Built up area

64. Floor Space Index (F.S.I)
• Floor Space Index (FSI), also
referred to as Floor Area Ratio
(FAR), is the ratio of total floor
area of a building (Built up area)
to the total Plot area (land). This
numeric value indicates the total
amount of area (on all floors)
you can build upon a plot.

65. How To Calculate FSI For Building?
• FSI regulates by Development control regulation department of a
particular location and according to the National Building Code of India.
• They will regulate the FSI value based on city zone, type of building and
other amenities. Construction can only build up to the FSI imposed by
the government.

66. Advantages & Disadvantages
Advantages
• It maintains the ratio of open space
to built space.
• It maintains the skyline line of the
city.
• A average F.S.I value ensures a good
development of the project.
• Maintaining equilibrium between
sustained, planned growth and
development is important.
Disadvantages
• Where, F.S.I is considered a poor
predictor of physical form. With less
F.S.I values the employment and the
idea of accommodating the ever
increasing population suffers.
• Therefore, with average F.S.I one
must turn it into an asset and design
the end product that caters and
solves all the problems.

67. Plinth area
• Plinth Area means the sum total of the floor area contained in all the storeys
of a building, the measurements for which shall be taken from the external
faces of the enclosing walls or other boundaries of such buildings.

68. Dam
• A dam is an impervious barrier construction across a river to store water.
• The side on which water gets collected is called the upstream side, and the
other side of the barrier is called the downstream side.
• The lake of water which is collected in the upstream side is called as
reservoir.
• This water is then utilized as and when it is needed.

69. PURPOSE OF A DAM
• To store and control the water for irrigation
• To store and divert the water for domestic
uses
• To supply water for Industrial uses
• To develop hydroelectric power plant to
produce electricity
• To increase water depths for navigation
• To create storage space for flood control
• To preserve and cultivate the useful aquatic
life
• For recreational purposes
Multipurpose Reservoirs
• A reservoir planned and
constructed to serve not only one
purpose but various purposes
together is called a multipurpose
reservoir.
• Reservoir, designed for one
purpose, incidentally serving
other purposes, shall not be called
a multipurpose reservoir.
• Hence a reservoir designed to
protect the down stream areas
from floods and also to conserve
water for water supply, irrigation,
industrial needs, hydroelectric
purposes etc. shall be called as
MULTIPURPOSE RESERVOIR.

70. FACTORS GOVERNING SELECTION OF SITE FOR DAM
• Suitable foundations should be available at the site selected for a particular
type a dam. For gravity dams, sound rock is essential. For earth dams, any
type of foundations is suitable with proper treatment.
• The river cross-section at the dam site should preferably have a narrow
gorge to reduce the length of the dam. However, the gorge should open out
u/s to provide large basin for a reservoir.
• The general bed level at dam site should preferably be higher than that of
the river basin. This will reduce the height of the dam and will facilitate the
drainage.
• A suitable site for the spillway should be available in the near vicinity. If the
spillway is to be combined with the dam, the width of the Gorge should be
such as to accommodate both.

71. Continued...
• Materials required for the construction should be easily available, either
locally or in the near vicinity, so that the cost of transporting them is as low
as possible.
• The reservoir basin should be reasonably water tight. The stored water
should not escape out through its side walls and bed.
• The value of land and property submerged by the proposed site should be
as low as possible.
• The dam site should be easily accessible so that it can be economically
connected to important towns and cities by rails, roads, etc.
• To establish site for labour colonies, a healthy environment should be
available in the near vicinity.

72. CLASSIFICATION OF DAMS- according to use
Storage Dam
• Storage dam is
constructed to store
water to its
upstream side during
the periods of excess
supply in the river (i.e.
during rainy season)
and is used in periods
of deficient supply
Diversion Dam
• Diversion dam supply
raises the water level
slightly in the river and
thus provides head for
carrying or diverting water
into ditches, canals or
other conveyance systems
to the place of use.
Detension Dam
• A detention dam is
constructed to store
water during floods and
release it gradually at a
safe rate when the flood
reduces.

73. Classification According to Hydraulic Design
Non-Overflow Dam :
the top of the dam is kept at a
higher elevation than the
maximum expected high flood
level.
Overflow dam
An overflow dam is the one which is designed to carry surplus
discharge over its crest.
Usually, in a river valley project, the two types of dams are
combined. The main dam is kept as a non – over flow dam and some
portion of dam is kept as overflow dam (spill way)at some suitable
location along the main dam.

74. Classification according to material
i. Rigid Dams
1. Solid Masonry gravity dam
2. Solid concrete gravity dam
3. Arched masonry dam
4. Arched concrete dam
5. Concrete buttress dam
6. Steel dam
7. Timber dam
ii. Non-Rigid Dams
1. Earth dam
2. Rockfill dam

75. Rigid Dams -Gravity dam
• A gravity dam is the one in which the external forces (such as water pressure,
wave pressure, silt pressure, uplift pressure etc.) are resisted by the weight of
the dam itself.
• A gravity dam may be constructed either of masonry or of concrete.
• Masonry gravity dams are now-a-days constructed of only small heights.
• All major and important gravity dams are now constructed of concrete only. A
gravity dam may be either straight or curved in plan

76. Rigid Dams -Arch dams
• An arch dam is a dam curved in plan and
carries a major part of its waterload
horizontally to the abutments by arch
action.
• The thrust developed by the water load
carried by arch action essentially require
strong side walls of the canyon to resist
the arch forces.
• The weight of arch dams is not counted
on to assist materially in the resistance of
external loads.

77. Steel Dams
• Steel dams are constructed with a frame work of steel with a thin skin
plate as deck slab, on the upstream side. Steel dams are generally of two
types. i. Direct Strutted type ii. Cantilever type
• In the direct strutted type, the load on the deck plate is carried directly to
the foundation through inclined struts.
• In the cantilever type, the deck is formed by a cantilever truss i.e. the deck
is anchored to the foundation at the u/s toe.

78. Earth Dams
• Earth dams are made of locally available soils and gravels.
• Therefore, these type of dams are used upto moderate heights only.
i. Homogeneous
embankment type :
• In this type, dam is
composed of a s ingle kind
of material.
• But this dam is structurally
weak.
• To check the seepage
through the dam a
horizontal filter drain or
rock toe is provided.
Zoned embankment type :
• In this type, the dam is made
up of more thn one material.
• Usually this dam consists of
central impervious core and
outer previous shell
• A suitable drainage s ystem, in
the form of horizontal drain or
a ro ck toe is also provided.
Diaphragam type embankment
:
• In this type, a thin
diaphragam of impermeable
materials is provided at the
centre of the section to
check the seepage.
• The diaphgram may be
made of cement masonry,
cement concrete or
impervious soils.

79. BRIDGES
• A bridge is a structure providing passage over an obstacle without closing
the way beneath.
• The required passage may be for a road, a railway pedestrian or a canal of a
pipeline. The obstacle to be crossed may be river, a road, a railway or a
valley.

80. CLASSIFICATION- Based on Materials used for
construction
a) Timber bridges
b) b) Masonry bridges
c) Steel bridges
d) Reinforced cement concrete bridges
e) Pre-stressed concrete bridges
f) Composite bridges

81. CLASSIFICATION- Based on Alignment
a) Straight or square bridges
b) Skew bridges

82. CLASSIFICATION- Based on The Relative position of bridge floor
1.Deck bridges are the bridges whose floorings are supported at the
top of the super structure.
2.Semi-through bridges are the bridges whose floorings are supported at some
intermediate level of the super structure.
3.Through bridges are the bridges whose floorings are
supported at the bottom of the super structure.

83. CLASSIFICATION- Based on Function of Purpose
a) Highway bridge
b) Railway bridge
c) Foot bridge
d) Viaduct and
e) Aqueduct etc.

84. CLASSIFICATION- Based on Position of High floor level
Submersible Bridges are the bridges whose
floor levels are below the high flood
level. During flood seasons, it allows the
water to pass over the bridge submerging
the communication route. In economic point
of view, these bridges are constructed.
Non-submergible
bridges are the bridges
whose floor levels are
above the high
flood level.

85. Classification based on Life :
a) Permanent bridges
b) b) Temporary bridges
Type of Superstructure :
a) Arch bridges
b) Truss bridges
c) Portal frame bridges
d) Balanced cantilever bridges
e) Suspension bridges etc.,
Span length :
a) Culverts (span less than 6m)
b) Minor bridges (span between 6 to 30m)
c) Major bridges (span above 30m
d) Long span bridges (span above 120m)
Loading :
a) Class AA bridges
b) Class A bridges
c) Class B bridges

86. COMPONENT PARTS OF A BRIDGE
Broadly, a Bridge can be divided into two major parts.
1. Sub structure 2. Super structure
The different types of funct ions adopted for bridges are:
• i. Spread foundation ii. Raft foundation iii. Pile foundation
• iv. Caisson foundation v. Well foundation
The substructure consists of the
following:
a. Abutments
b. Piers
c. Wi ng walls
d. Approaches
e. Foundations for the piers and
abutments
2. Super structure : The super
structure is that part of the bridge
over which the traffic moves with
safely.It consists of:
a. Decking
b. Parapet or hand rails, guard
stones etc.
c. Bearing

87. Water supply
DIFFERENT PHASES
• Selection of source
• Collection of conveyance water
• Treatment of water
• Pumping
• Distribution

89. QUALITY OF WATER
Physical parameters of water
quality
1. Colour
2. Temperature
3. Taste and odour
4. Turbidity
5. Specific conductivity
Chemical characteristics
1. Total hardness
2. pH and alkalinity
3. Hardness
4. Chlorides
5. Dissoved solids
6. Sulphates
7. Nitrogen compounds
8. metals
Biological characteristics
1.Aerobic bacteria
2.Anaerobicbacteria

90. Rainwater harvesting
• Rainwater harvesting is a type of harvest in which the rain drops are collected and stored for the future use,
rather than allowing them to run off. Rainwater can be collected from rivers or roofs and redirected to a deep
pit (well, shaft, or borehole), aquifer, a reservoir with percolation, or collected from dew or fog with nets or
other tools. Its uses include water for gardens, livestock, irrigation, domestic use with proper treatment, indoor
heating for houses, etc. The harvested water can also be used as drinking water, longer-term storage, and for
other purposes such as groundwater recharge
• rooftop harvesting.: With rooftop harvesting, most any surface— can be used to intercept the flow of
rainwater and provide a household with high-quality drinking water and year-round storage.
• The reasons for using rainwater harvesting systems answer three questions:
What: Rainwater harvesting will improve water supply, food production, and ultimately food security.
Who: Water insecure households or individuals in rural areas will benefit the most from rainwater harvesting
systems.
How: Since rainwater harvesting leads to water supply which leads to food security, this will greatly contribute to
income generation.
• Tamil Nadu was the first state to make rainwater harvesting compulsory for every building to avoid
groundwater depletion. The scheme was launched in 2001 and has been implemented in all rural areas of
Tamil Nadu.