A study project on Low cost housing. The various construction techniques available for reduction of cost of a building are discussed. A study is also performed on the citizens of Vijayawada and the interpreted results are shown.
Unit 4_Part 1 CSE2001 Exception Handling and Function Template and Class Temp...
Low cost housing
1. A STUDY ON
LOW COST HOUSING
BY:-
B.SAI KIRAN
(15761A0111)
2. OBJECTIVES
• To examine the present housing scenario in India.
• To study the housing requirements of people.
• To study various Construction techniques which can be used to
reduce the cost of construction.
• Study of alternative materials which can be used for Low cost
housing.
• To Study the Human behavior towards Low cost housing.
• Cost estimation of normal building and the identifying the percentage
reduction in cost for low cost building.
3. OVERVIEW
• According to the 2011 Census, there were 1.77 million homeless
people in India, or 0.15% of the country's total population.
• There is a shortage of 18.78 million houses in the country.
• Indian population expanding by 1.3% every year, has long been a
problem for its government. Providing affordable housing remains a
major concern of the government as 37% of its population remains
below the International poverty line (US $1.5 a day).
4. INTRODUCTION
• House is the 3rd basic need of Humans after Food and Clothing.
• Low Cost Housing is a new concept which deals with effective
budgeting and following of techniques which help in reducing
the cost construction through the use of locally available
materials along with improved skills and technology without
sacrificing the strength, performance and life of the structure.
• Low cost housing is done by proper management of resources
and use of improved building technologies.
• The use of natural materials like straw, bamboo, fibres (jute,
coir), earth etc. is a centuries old practice in India.
5. SCOPE:-
• The cost estimation is done roughly by referring to standard rates
and percentage saving suggested for Low cost techniques from and
experimentations done by BMTPC and CBIR. This may result lower
degree of accuracy.
• The survey is done on a small group of people while considering
heavy population the analysis done may not be pin pointed.
• The survey is done in a single place with urban conditions
(Vijayawada). This results may not hold good in case of rural
conditions. Thus there is a chance for deviation of results.
• The cost is estimated assuming ideal conditions and may vary
depending upon the suitability and availability.
6. METHODOLOGY
A Questionnaire was prepared and a survey has been conducted among different
income level people to analyze the housing needs of various communities of people.
The study of materials and Improved construction techniques for affordable
housing is done by referring to various Text books, Journals and Case studies.
Human behaviour towards Low cost Housing and factors influencing the consumer for buying
a house is analysed by conducting a survey among a group of people with a Questionnaire.
To estimate the percentage difference of cost a Residential House was considered and is
designed using general methods followed in practice, and Low cost housing techniques and
materials separately. The cost estimation is done for both the above cases and the cost
difference is calculated.
Various Journals and code books were referred to examine present housing scenario in India
7. PREPARATION OF PROPER PLAN
• It is found that the Square plot will
be more economical than
Rectangular plot.
• This is because the boundary wall
length will be shorter for Square
plot compared to Rectangular plot.
• For same area the perimeter will
be less for Square plot compared
to Rectangular plot.
• The cost of Brickwork, Plastering,
Wall base, Paint will be saved.
10. • In areas where the Bearing capacity of the soil is
low and the soil is expansive; the conventional
mode of providing footing is Spread Footing.
• The Under-Reamed piles are considered as
economic and ideal in such cases.
11. • The Under-Reamed piles are
bored concrete piles having
one or more enlarged bases
towards bottom called Reams
(or) Bulbs.
• If bulbs are provided lower
than critical depth of moisture
movement; where the soil has
nearly stable moisture
content; the foundation will
anchored to the ground and it
will not move with Swelling
and Shrinkage of Soil.
• Designed according to IS 2911
Part3.
12. HYPERBOLIC PARABOLOID FOOTING:-
• In soils of low bearing capacity the base of Footing of
columns should be enlarged to larger sections.
• In such cases it is very economical to use Hyperbolic
Paraboloid footings.
• Hyper footings are reinforced concrete footings resembling
shape of an Umbrella. They are made of two parabolas one
over the other and they have shell like structure.
• The degree of saving is 10-30% depending upon the soil
characteristics as the solid Trapezoid is replaced by
Hyperbolic paraboloid shell.
13. ARCH FOOTINGS:-
• In ordinary soils, it is suggested to adopt Arch Foundations.
• This type of foundation was used in olden times where in spread
foundation is replaced by inverted arch.
• It reduces the construction cost up to 40%.
• Advantage of this is-In soft soils that the depth of foundation can be
greatly reduced.
15. STABILIZED AND COMPACTED MUD
BLOCKS:-
• These are made of mud stabilized with 5% cement/lime etc. and
compacted in block making machine with no burning.
• They are economical, energy saving, and are easy to manufacture.
16. HOLLOW CONCRETE BLOCKS:-
Concrete blocks having core void area larger than 25% of the gross
area is termed as hollow concrete blocks.
ADVANTAGES:-
• Cost effective due to saving of
material.
• Use of larger size concrete block
reduces number of joints in
work and hence helps in saving
mortar also.
• Rapid execution of work.
• Better insulation properties.
17. FLYASH GYPSUM BRICKS:-
• Fly-ash Gypsum bricks are good substitute for burnt clay bircks for
the areas in which fly-ash is readily available.
• These bricks can be manufactured with a composition of 92% fly-
ash, 4.5% powdered kankar lime and 3.5% gypsum in volumetric
proportion.
• A compressive strength of 5-6 N/mm2 is expected to be achieved
from these bricks.
18. RAT-TRAP BOND:-
• Rat trap bond is a brick masonry method of wall construction, in
which bricks are placed in vertical position instead of conventional
horizontal position and thus creating a cavity (hollow space) within
the wall.
• This is where approximately 30% Material (brick and mortar) is
saved and thus overall construction cost is reduced. Cavity provides
effective thermal and sound insulation. This makes rat trap bond
energy and cost efficient building technology.
19. BRICK JALIS:-
• Brick Jalis made by widening and leaving openings in the vertical
joints can provide aesthetic patterns and ventilation holes that can
take the place of window openings at the little cost.
• Can also be used for parapet walls and boundary walls.
• Instead of using regular walling system of lintel and window system,
jaliwork can help reduce the cost significantly.
22. FILLER SLAB:-
• Filler slab technology is a simple and a very innovative technology
for a slab construction.
• In the figure below the fibers above neutral axis will be in
Compression and fibers below neutral axis will be in Tension.
• That means if we want to optimize the structure we can remove
concrete from the tension zone where it is not much needed.
• Hence we replace that part of concrete using light weight and low
cost filler material. This method of construction is called Filler slab.
23. FILLER SLAB:-
• Light weight, inert and inexpensive materials such as low grade
Mangalore tiles, Burnt Clay Bricks, Hollow Concrete blocks,
Stabilized Mud blocks/ Hollow Mud blocks, Clay pots, Coconut
shells etc. can be used as filler materials. These materials are
laid in the grids of steel reinforcement rods and
concreting/concrete topping is done over them.
• Use of Filler Slab leads to economy to the extent of 30% as
compared to conventional R.C.C slab.
24. PRE-CAST R.C PLANK ROOFING:-
• Plank and joist roof is a building system in which precast reinforced
cement concrete planks – rectangular slab elements – are placed on
precast RCC joists. The roof gets completed with in-situ concrete poured
over the haunches in planks and over the partially precast joists, thus
ensuring monolithic action of individual precast elements.
• Pre-casting of roof leads to substantial reduction in construction time
• 15 to 20% saving in cost possible because of no shuttering and
reduction in steel quantity.
25. PRE-CAST RCC PLANKS:-
• These are pre-cast concrete slabs, typically 30 cm wide x 1.5 m long, although the
length can vary from1.2-1.8 m (4 to 6 feet) depending on size of room. The planks are
made partly 3 cm thick and partly 6 cm thick with a 10 cm wide tapered concrete
filling provided for strengthening the haunch portion for shear during handling and
erection. The plank uses nominal MS reinforcement, typically 6 mm bar and concrete
of grade not less than M-20. One 30 X 150 cm plank weighs about 150 kg and can be
handled manually.
PARTIALLY PRE-CAST RCC JOISTS:-
• It is a Square shaped joist 15 X15 cm wide with stirrups projecting out. The overall
depth of joist with in-situ concrete is 21 cm.
CONCRETE FILLING:-
• Planks are placed on joists and in-situ concrete is poured over the haunches provided
in the planks and the gaps between the planks over the joists. Monolithic action of the
slab elements is ensured by leaving hooks projecting out of joists and providing
reinforcement across the joists over haunch portion of planks, tying them together
and pouring in-situ concrete over it. .
26. PREFAB BRICK PANEL AND JOIST ROOFING:-
• In this system, concrete is used in maximum compressive stress
zone and bricks in less compressive stress zone.
• The method of precast fabrication is adopted for making precast
concrete joists and brick panels.
27. PREFAB BRICK PANEL AND JOIST ROOFING:-
Prefab brick panels are made of first class bricks and 2reinforced with two MS bars
of 6 mm dia. The joints are filled with either M20 concrete or cement mortar 1:3 (1
cement: 3 course sand). The length of the brick panels varies from 900 mm to 1200
mm depending upon the room size, but the width is normally kept at 530 mm to allow 36
to 40 mm wide gap between the bricks for placing reinforcement with proper cover
and for laying concrete.
28. PREFAB BRICK PANEL AND JOIST ROOFING:-
• Partially Precast Joist
• It is rectangular shaped concrete joist 130 mm wide, and 100 to 125
mm deep (Fig. 2). Their stirrups are kept projecting upward to
provide 215 to 235 mm as its overall depth with in-situ concrete
(M20).
• The Joists are placed in position and are propped.
• Brick panels are placed over joists.
• All gaps between panels are filled with M20 concrete by holding a
wooden strip under them which is removed by sliding sideways just
after the completion of concreting work.
29. FUNICULAR SHELL ROOFING:-
• A Funicular Shell is a doubly curved shells deriving strength from
their shape. The shells can be cast using simple masonry moulds.
• They are made with materials of good compressive strength such as
waste stone pieces and brick tiles and supported on reinforced
concrete edge beams.
• The reinforced concrete beam supports and distributes the
horizontal thrust of the funicular shell. The beam can be
conventionally cast along with the funicular shell.
30. FUNICULAR SHELL ROOFING:-
• The mould is supported between the edge beams. Timber planks are
used to bridge the gap between the edge of the mould and the edge
beam. The shell comprises of the materials – bricks, stone waste – laid in
the funicular profile topped with cement-sand mortar and concrete
screed.
• After the shells have been cast, the valley spaces which are formed
between the shells can be filled with light-weight material like brick jelly
lime concrete and finished flat. The infill will enable the construction of
an intermediate floor which can be used to build above.
31. FERROCEMENT CHANNEL ROOFING:-
• This building system uses pre-cast ferrocement roofing channels of
a segmental arch profile which are placed adjacent to each other
and spanning over two supports. After partly filling the valley
between channels with concrete, the channels form an idealized T-
beam and are able to carry the load of a roof / floor.
• Ferrocement comprises of a uniform distribution of reinforcement
as wire mesh encapsulated in rich cement mortar.
32. FERROCEMENT CHANNEL ROOFING:-
• FC Channels are pre-cast shell units made with rich cement mortar
(1:2 to 1:3) and reinforcement consisting of a continuous layer of
chicken mesh with steel bars provided at two ends of the channel.
• These shell units are cast either manually on a masonry mould or
mechanically on steel moulds mounted on table vibrator.
• Any lateral moment and deflection of FC Channel gets balanced by
thrust of adjacent channel. In order to balance the channel
movement at ends, restraining beams must be provided.
33. FERROCEMENT CHANNEL ROOFING:-
• After the Channels have been placed side by side, they are joined
together with a concrete infill of at least M15 grade (1:2:4) laid to
150 mm thickness. This concrete completes the T-beam structural
action of the FC Channels and creates a basic roof. In case of an
intermediate floor, the remaining portion of the valley can be filled
the with lean concrete, brick jelly lime concrete or light-weight
material and finished with a floor.
• 20% saving in cost possible because of reduction in steel quantity
and elimination of coarse aggregates and shuttering.
36. SURVEY ANALYSIS:-
A Questionnaire has been prepared and a survey has been conducted in
Vijayawada, Andhra Pradesh to analyze the housing needs and
requirements of people.
From the survey, the analysis shows that
• More than 75% of people lives in rent houses.
• Every one wishes to have their own house.
• More than 90% of the people preferred to have the layout of their
house according to Vaastu.
• The lower income groups (i.e., <10,000 per month) wish to have a
house through government schemes.
• More than 95% people ranked Strength and Durability as primary
requirement and Aesthetic appearance as secondary requirement.
37. COST ANALYSIS:-
No Item Unit
Rate
(US$)
Conventional brickwork Rat-trap bonded brickwork
Quantity Amount (US$) Quantity Amount(US$)
Materials
1 Bricks No 0.02 350.00 7.00 284.00 5.68
2 Sand m3 0.32 0.28 0.09 0.17 0.05
3 Cement (10kg bag) No 6.17 0.67 4.13 0.40 2.47
Labour
1 Mason (highly
skilled)
No 1.70 0.35 0.60 0.35 0.60
2 Mason (2nd class ) No 1.49 1.05 1.56 0.80 1.19
3 Unskilled labour No 1.06 2.96 3.14 1.96 2.08
Add 2% tools and plant charges 0.34 0.25
Add for scaffolding- superstructure: 0.42/m3 0.42 0.42
Total (per m3) 17.71 13.08
Savings 26.11%
38. COST ANALYSIS:-
No Item Unit
Rate
(US$)
Conventional slab Filler slab
Quantity Amount
(US$)
Quantity Amount(US
$)
Materials
1 Concrete,
including
labour
m3 38.6 1.00 38.6 0.80 30.88
2 Reinforcement ton 36.12 0.80 28.89 0.38 13.72
3 Steel cutting,
bending
ton 3.87 0.80 3.09 0.38 1.47
4 Mangalore tiles No 0.06 N/A N/A 65.00 4.14
Labour
1 Mason
(2nd class )
No 1.49 N/A N/A 0.20 0.30
2 Unskilled labour No 1.06 N/A N/A 0.80 0.85
Add 2% tools and plant charges 0.11 0.11
Total (per m3) 84.32 65.20
Savings 22.68%
39. COST ANALYSIS:-
ELEMENT NORMAL R.C.C BUILDING LOW COST BUILDING
FOUNDATION SPREAD FOOTING UNDER REAMED PILES
WALL ENGLISH BOND
BRICK WALL
RAT TRAP BOND
BRICK WALL
ROOF R.C.C SLAB FILLER SLAB
ELEMENT SAVINGS IN LOW COST
BUILDING
FOUNDATION 25%
WALL 30%
ROOF 30%
The percentage savings are taken according to the recommendations of BMTPC and CBIR
From their experimentations.
40. APPLICATIONS
• The main objective of Low cost housing is to provide shelter for poor
people and to accommodate the housing needs of growing population.
• The concept of Low cost housing is also useful when it is needed to
provide Temporary shelter for Disaster Refugees after natural
calamities.
• During massive construction projects (Dams, Tall Buildings etc.,) it is
required to provide temporary shelter for Labor until completion of
project. In this case the concept of Low cost housing becomes handy.
• While construction of Mass housing projects with low funding the
concept of Low cost housing can be used.
41. CONCLUSION:-
From the survey conducted at Vijayawada, we concluded that;
1. More than 70% of people live in rent houses and wishing to have their own
house.
2. The strength, Durability and aesthetic appearance is the major requirement of all
people.
3. Everyone wants the design layout of their house according to Vaastu.
4. The low income people wish to have their house through Government schemes
and the remaining through Loans and Own sources.
5. The affordability of a Residential building can be brought to the range of Low and
Medium class income people through adopting to Improved Building
Technologies and proper usage of Natural resources.
6. The cost of a building can be reduced up to 25-30%
7. The strength of the building is not compromised in Low cost Housing and in fact
the buildings are made more effective.
8. There is a illusion among most of the people that Low cost housing is done using
Less quality materials.
9. Low cost materials available at Vijayawada are Stones from Quarries, Sand,
Laterite, Soil, Wood which can be used to build Low cost Housing.
42. REFERENCES:-
• Hand book of Low Cost Housing by A.K.Lal – New Age International
Publishers.
• Low cost Housing – G.C. Mathur, IBH publishers.
• “Low cost Housing and Vastushastra” –Deepak Kumar, Standard
publishers distributors.
• “APPROPRIATE TECHNOLOGIES FOR LOW COST HOUSING” by A.G
Madhava rao – OXFORD & IBH Publishing Co.Pvt.Ltd
