1. UNIT-I Definition of building: Types of building
A building can be defined as a structure consisting of walls, floors and roofs to provided covered space for different uses such as residence, education hospitalization, entertainment, worship etc.
Types of building
According to the national building code of India building are classified based on occupancy as follows:
1.  Residential buildings
2.  Educational buildings
3.  Institutional buildings
4. Assembly building
5. Business building
6. Mercantile buildings
7. Industrial buildings
8. Storage building
9. Hazardous building

2. Group A: Residential Buildings
This occupancy type shall include any building providing sleeping and living accommodations to related or unrelated groups of people, with or without cooking or dining facilities. This Occupancy shall be subdivided as follows:
A1:Single Family Dwelling
These shall include any building or row type buildings by distances required by Code and having independent access to the plot, which is used as private dwelling by members of a single family.
A2:Two Family Dwelling
These shall include any building, row type buildings by distances required by Code and having shared or independent access for two families and having facilities for living, cooking and bathroom facilities independent of each other.
A3:Flats or Apartments
These shall include any building which is provided for more than two families, having facilities for living, cooking and bathroom facilities independent of each other.
A4:Mess, Boarding Houses, Dormitories and Hostels
These shall include any building in which sleeping, living accommodations and bathroom are provided for groups of related or unrelated persons, with or without common dining and facilities, and with common cooking under single management control or with individual or group cooking facilities.

3. Group B : Educational Buildings
A5:Hotels and Lodging Houses
These shall include any building, under single management, in which sleeping, living accommodation and bathroom facilities are provided with or without dining facilities but without cooking facilities.
Group B : Educational Buildings
This occupancy type shall include any building in which education, training and care are provided to children or adults. This Occupancy shall be subdivided as follows:
B1: Educational Facilities up to Higher Secondary level
B2: Facilities for Training for Above-secondary level
B3: Pre-school Facilities
Group C : Institutional Building
Buildings classified under this occupancy shall include for purposes of institutional care of the occupants such as medical or nursing care of persons suffering from illness or infirmity due to mental condition. These buildings shall ordinarily provide accommodation for sleeping, dining and other provisions approved by the authority for the occupants. This occupancy shall be subdivided as follows:
C1 :Hospital
C2: Institution for care of Children
C3:Custodial Institution
C4: Penal Institution

4. Group D: Assembly Building
Buildings under this Occupancy group shall include any building in which groups of people assemble for recreation, social, religious, political, cultural, travel and similar purposes. This Occupancy shall be subdivided as follows:
D1:Large Assembly with Fixed seats
D2: Small Assembly with Fixed seats
D3:Large Assembly without Fixed seats
D4:Small Assembly without Fixed seats
Group E: Business Building
These shall include any building which is used for any business transaction other than mercantile. This Occupancy shall be subdivided as follows:
E1: Office
E2: Research and Testing Laboratories
Group F: Mercantile Building
This occupancy type shall include any building which is used for display and sale of merchandises. This Occupancy shall be subdivided as follows:
F1:Small Shops and Market
F2:Large Shops and Market

5. Group G: Industrial Buildings
These include any Buildings in which products or material of all kinds are fabricated, assembled or processed. For example assembly plants, power plants, gas plants etc.
Group H: Storage Buildings
Buildings under this Occupancy group shall include any building used primarily for storage or sheltering of goods, wares, merchandises, vehicles or animals.
Group I : Hazardous Buildings
Any Building used as storage, industrial, research and other facilities dealing with hazardous material in excess quantity or any micro-biological facilities shall be categorized in this Occupancy group.

6. Foundation Common Components of Building and their function
A building can be broadly divided in two parts
Substructure
Superstructure
Substructure: The substructure is the lower portion of the building, which is located below ground level which transmits the load of the superstructure to the subsoil. It includes Foundations.
Foundation
The basic function of foundation
To Transmit the load from building to the subsoil, in such a way that Settlement are within permissible limit.
The soil does not fail in shear
Reduce the load intensity
Even distribution of load
Provide level surface

7. Superstructure
The superstructure is that part of the building which is above the ground and which serves the purpose of building’s intended use.
It includes •Plinth •Wall • columns •Beams •Floors •Roofs and slabs •Lintel and arches •Chajjas •Parapet •Steps and stairs • Doors and Windows •sill
Plinth: Plinth is that part of the building between surrounding ground surface and floor space immediately above the ground.
Plinth resists the entry of rain water inside the building, entry of animals, insects.
General plinth height is 45, 60, 75, 90, 120 cm.

9. Wall: The walls are building blocks of bricks or stones.
They divide the building space into various space into various rooms.
They support slabs and beams.
They safely transmits the loads coming on them from beams and slabs to the foundation.
They provide privacy and protection against heat, cold, rain, noise, dust winds.
They offer resistant to firewalls may be of Brick masonry and Stone masonry.

11. Columns: Columns are vertical members along which beams and slab/roof is supported.
They are square, rectangular and circular in shape in C/S.
Beams: Beams are horizontal members above which the slabs are provided.
The beams are instead supported on walls and columns .
They are generally 20, 39, 45, 60 cm thick and deep members as per structural design.
Floor: A floor is a plane area to support occupants, furniture's, and equipments.
Roof: The upper most part of the building constitutes the roof.
The Slab and roof encloses the space and offers protection from rain, heat, snow, wind, sound, fire. Slabs are 10, 12, 15 cm thick.

13. Lintel and Arch
Lintel is a horizontal member which is placed across the opening.
An arch is normally a curved member of wedge shaped building blocks holding each other with mutual pressure.
Chajjas
Chajjas are provided on external wall at opening to get protection from rain, snow and heat.
They are weather sheds.
Their thickness tapers from 100 to 75 mm and projection is 30, 45, 60, 75, 90 cm.
Parapet:
Parapet is generally 10cm thick partition wall constructed above slab to enclose the terrace open to sky.
Thickness is 10 to 15 cm height is 1.0 m to 1.2m.
Sills:
Sills are lower portion of window and ventilator opening.

15. Steps and Stairs
Steps and stairs are to be provide access between different levels. Stairs should be properly located to provide easy access and fast services to the building.
In one flight maximum 8 steps should be provided.
For more than 8steps it is recommended to provide landing.
Generally for residential building width of stair is 1.0 m and 1.2 m.
No of risers = Total height of floor/Height of riser
No of tread=Number of riser-1

17. Doors and windows
A door provides a connecting link between rooms, allowing easy free movement in the building.
Window are opening provided in walls.
Doors and windows provide lighting and ventilation.
They provide resistance to weather, sound and heat.
They provide security and privacy.

18. Types of structure
Load bearing Structure
Framed structure
Load Bearing Structures:
In this type of structures loads from roof/ slab or trusses are transmitted through walls to the soil below the ground.
This type of structures are adopted where hard strata are available at shallow depth.
The structural elements like beams, slabs rests directly on the walls.

20. Framed Structures:
Reinforced cement concrete structures are the most common type of construction today.
They consist of a skeleton of beams & columns.
The load is transferred from beams to the columns and column intern transfer the load directly to the subsoil through footing.
Framed structures are suitable for multistory building subjected to variety of extreme loads like compressive, tensile, torsion, shear along with moment.
The open spaces in the skeleton are to be filled with brick walls or glass panels.

23. Types of foundation
Foundations may be broadly classified as
(a) shallow Foundation
(b) Deep foundation
(a) Shallow Foundation: According to Terzaghi, a foundation is shallow if its depth is equal to or less than its width.
Types of shallow foundation:
Spread footing
Combined footing
Strap Footing
Mat Foundation or Raft Foundation

24. Spread Footing:-Spread footings are those which spread the super-imposed load of wall or column over larger area. Spread footing support either column or wall.
It may be following kinds
Single footing for column: In which the loaded area of column has been spread to the large size through single spread. The base is generally made of concrete.
Stepped footing for column: This type of footing provided for heavily loaded column which required greater spread with steps. The base is generally made of concrete.
Sloped footing for column: In this type of footing concrete base does not have uniform thickness but is made sloped.
Wall footing without step: It consist of concrete base without any steps including masonry wall.
Stepped footing for wall: It consist of masonry wall have stepped footing with concrete base .

26. Grillage Foundation
It is special type of isolated footing generally provided for heavily loaded steel column and used in those location where bearing capacity of soil is poor.
The depth of such foundation is limited to 1 to 1.5 m.
The load of steel column is distributed over very large area by means of two or more tiers of steel joints.
Each layer being laid at right angle to the layer below it.

28. Combined Footing:
A spread footing which supports two or more columns is termed as combined footing.
The combined footing may be of following kinds.
Rectangular combined footing: The combined footings will be provide in rectangular in shape if columns carry equal loads. The design of rectangular combined footing should be done in such way that centre of gravity of column coincide with centroid of footing area.
Trapezoidal combined footing: If columns carry unequal loads the footing is of trapezoidal shape are provided.
Combined column-wall footing: It may be required to provide a combined footing for column and wall. Such combined footing are shown in fig.

31. Strap Footing:
If a Independent footing of two columns are connected by a beam, it is called a strap footing.
A strap footing may be used where the distance between the column is so great that trapezoidal footing becomes quite narrow.
The strap does not remain in contact with soil and does not transfer any pressure to the soil.

33. Raft foundation:
A raft Foundation is a combined footing that covers the entire area beneath a structure and support all the wall and column.
They are used in areas where the soil masses contains compressible lenses or the soil is sufficiently erratic so that differential settlement would be difficult to control.
Raft foundation may be divided in to three types based on their design and construction.
Solid slab system
Beam slab system
Cellular system
All the three types are basically the same, consisting of a large, generally unbroken area of slab covering the whole or large part of structure.

36. Deep foundation Pile Foundation
Deep foundation are those in which the depth of foundation is very large in comparison to its width.
Deep foundation may be of following types
Pile foundation
Pier foundation
Caissons or Well foundation
Pile Foundation
Pile Foundation is that type of foundation in which the loads are taken to a low level by means of vertical members which may be timber, concrete or steel.
Pile foundation may be adopted when no firm bearing strata is available and the loading is uneven.
Piles may be of following types
End bearing piles
Friction Pile
Compaction pile

37. End bearing piles: This types of piles are used to transfer load through water or soft soil to a suitable bearing stratum.
Friction Pile: Friction piles are used to transfer loads to a depth of friction load carrying material by means of skin friction along the length of piles.
Compaction pile: Compaction piles are used to compact loose granular soils, thus increasing their bearing capacity.

39. Pier foundation:
A Pier foundation consist of cylindrical column of large diameter to support and transfer large superimposed load to the firm strata below.
Generally, pier foundation is shallow in depth than the pile foundation.

41. Well Foundation:
Well Foundation or Caisson are box like structures which are sunk from the surface of either land or water to the desired depth.
They are much larger than the pier foundation or drilled caissons.
Caisson foundations are used for major foundation works like
Bridge piers
Docks
Large water front structure such as pump house.

43. Types of Loads
Various loads are taken into account while designing the foundation of a structure.
Dead loads;
Live load;
Wind loads;
Earthquake loads;
Erection loads; and

44. Dead Load:
Dead load comprises of the weight of all walls, partitions, floors and roofs including all other permanent construction in the building.
Wind load:
It is considered as basic wind pressure which is equivalent static pressure in the direction of the wind
Wind pressure=kV2
Where k=co-efficient,0.006
V=wind velocity
Wind pressure always acts in the vertically exposed surface of the walls and columns.

45. Live Load:
Live Loads consist of moving or variable loads due to people or occupants, their furniture, temporary stores, machineries.
Erection Load:
All loads required to be carried by the structure or any part of it due to storage or positioning of construction material and erection equipment including all loads due to operation of such equipment, shall be considered as erection loads.
Earthquake load:
An earthquake load produced waves in every possible direction below ground.
As per intensity or scale of earthquake, jerks and shocks are acting on the earth.
As per the location of the building in the prescribed zone of earthquake coefficients of earthquake loads are decided.

46. bearing capacity of soil
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. 
Bearing capacity is the power of foundation soil to hold the forces from the superstructure without undergoing shear failure or excessive settlement.
Foundation soil is that portion of ground which is subjected to additional stresses when foundation and superstructure are constructed on the ground.

48. The following are a few important terminologies related to bearing capacity of soil.
Ultimate Bearing Capacity (qf): It is defined as the minimum gross pressure intensity at the base of foundation at which the soil fail in shear.
Net ultimate Bearing Capacity (qn): It is the minimum net pressure intensity causing shear failure of the soil.
Allowable Bearing Pressure (qa): It is the maximum pressure on the foundation soil which is subjected to considering both shear failure and settlement.
It is pressure intensity at which neither the soil fails in shear nor excessive settlement.

49. Safe Bearing Capacity (qs):
The maximum pressure which the soil can carry safely without rick of shear failure is called the safe bearing capacity.
Calculation of safe bearing capacity of soil:
Calculate the ultimate resistance of soil ( R ) using the formula given below.
R = (w * h) / d
Where, R = Ultimate resistance of soil (in kg)
d = Average depth of impression (in cm)
w = Weight of the solid square cube (in kg)
h = Height of fall of solid cube (in cm)
If “A” is the cross-sectional area of the solid cube, then resistance of soil per unit area is calculated using following formula.
Resistance of soil per unit area (in kg/cm2) = R / A
Safe bearing capacity (in kg/cm2) = R / (A * F.O.S)
Where, F.O.S = Factor of safety

50. Safe bearing capacity value based on IS code
Type of Soil / Rock
Safe Bearing Capacity (kg/cm2)
Rock
32.40
Soft rock
4.40
Coarse sand
Medium sand
2.45
Fine sand
Soft shell / Stiff clay
1.00
Soft clay
Very soft clay
0.50

51. Method of improving bearing capacity of soil
The following techniques can be used for improving bearing capacity of soil as per the site condition.
Increasing depth of foundation
Draining the soil
Compacting the soil
Confining the soil
Replacing the poor soil
Using grouting material
Stabilizing the soil with chemicals

53. 1. INCREASING DEPTH OF FOUNDATION
At deeper depths, the over burden pressure on soil is higher; hence the soil is more compacted at deeper depth. As a result it shows higher bearing capacity.
This is applicable only for sandy and gravel soils.
This method of improving bearing capacity of soil but it is not applicable if the subsoil material grows wetter as depth increase.
This method has a limited use because with increase in depth the cost of foundation also increases.
2. DRAINING THE SOIL
With increase in percentage of water content in soil, the bearing capacity decreases. In case of sandy soil, the bearing capacity may reduce as much as 50% due to presence of water content.
Cohesion less soils (i.e. sandy & gravelly soils) can be drained by laying the porous pipes to a gentle slope, over a bed of sand and filling the trenches above the pipes with loose boulders.

54. 3. COMPACTING THE SOIL
If we compact soil then there will be increase in its density and shear strength. As a result the bearing capacity of soil also increases.
There are many methods of compacting soils on site.
Using an appropriate roller as per the soil type to move at a specified speed.
4. CONFINING THE SOIL
In this method, the soils are enclosed with the help of sheet piles.
This confined soil is further compacted to get more strength.
This method is applicable for shallow foundations.

55. 5. REPLACING THE POOR SOIL
In this method the poor soil is first removed and then the gap is filled up by superior material such as sand, stone, gravel or any other hard material.
In order to do this, first excavate a foundation trench of about 1.5 m deep, and then fill the hard material is stages of 30 cm.
Then compact the hard material at every stage. This method is useful for foundations in black cotton soils.
6. USING GROUTING MATERIAL
This method is applicable for soils where there is presence of pores, fissures or cracks etc underneath the foundation.
In this method, poor soil bearing strata is hardened by injecting the cement grout under pressure.
For proper distribution of the cement grout, the ground is bored and perforated pipes are introduced to force the grout.

56. 7. STABILIZING THE SOIL WITH CHEMICALS
This method of improving bearing capacity of soil is costly and applied in exceptional cases.
In this method, chemical solutions, like silicates of soda and calcium chloride is injected with pressure into the soil.
These chemical along with the soil particles form a gel like structure and develop a compact mass.
This is called chemical stabilization of soil and used to give additional strength to soft soils at deeper depths.

57. Excavation for foundation Excavation of foundation trenches can be done either manually with help of conventional implement or with the help of special mechanical equipment. Conventional implement as shown in fig. which are spade, phawrah, pick axe, crow bar, rammer, wedge, boning rod, sledge hammer, basket, iron pan, line and pin.

58. Special mechanical equipment include drag shovel which can excavate the foundation trench up to a width of 1.7m.
Also multi-bucket trencher which can excavate trenches up to 1.5 m width and 5m deep.
The boom is raised or lowered as required by driver moving a lever and can be locked in any position.
The soil is carried up from trench by bucket which is having cutting teeth.

60. Dewatering from foundation
Construction of some buildings, powerhouses, dams, and many other structures requires excavation below the water table into water-bearing soils.
Such excavations require lowering the water table below bottom of the excavation to prevent sloughing and to ensure dry, firm working conditions for construction operations.
Dewatering can be done the following methods:
1. Ditches and sumps
2. Well point systems
3. Shallow well system
4. Deep well system
5. vacuum method
6. Electro-osmosis

61. Ditches and sumps Well point systems
This is the simplest form of dewatering used in shallow excavation in course grained soil.
Shallow pits called sumps are dug along the periphery of area.
The water from slopes or sides flows under gravity and is collected in sumps from which it is pumped out.
Well point systems
Well point is cm diameter metal or plastic pipe 60 cm – 120 cm long which is perforated and covered with a screen.
Well points are connected to cm diameter pipes known as riser pipes and are inserted into the ground by driving or jetting.
The upper ends of the riser pipes connect to a header pipe which connected to a pump.
The ground water is drawn by the pump into the well points through the header pipe and discharged.

64. Shallow wells system
Shallow wells include surface pumps which draw water through suction pipes installed in bored wells drilled by the most appropriate well drilling.
The limiting depth to which this method is employed is about 8 m.
The shallow well can be used to extract large quantities of water from a single hole.
On congested sites use of smaller number dewatering points is preferred as shallow wells system.
The initial cost of installation is more compared to well points.

65. Deep Wells system
When water has to be extracted from depths greater than 8 m and it is not feasible to lower the pump and suction pipe.
The diameter of pipe will be 150 – 200 mm which is larger than the well inner casing.
The inner well casing has a perforated screen over the depth requiring dewatering and terminates below in 1 m of unperforated pipe.
After the slotted PVC or metal well screen (casing) has been installed it is surrounded by backfill over the unperforated pipe length and with graded filter material over the perforated length.
In deep well system submersible pump should be used for dewatering.

67. Vacuum method
The above method are effective only in course grained soils.
For fine grain soil well point system and deep well system can be adopted for dewatering.
In vacuum method a hole of about 25 cm diameter is created around the well point and the rise pipe by jetting water under sufficient pressure.
While the jetting water is still flowing, medium to course sand is rapidly shoveled in to the hole to fill it up to about 0.75m to 1m from the top.
The top portion of the hole is then sealed up by tamping cement or clay.
Vacuum pumps are used to create vacuum in sand filling.

68. Electro-osmosis method
This method is used for fine grained cohesive soils such as clay, which can be drained water by using electric current.
If direct current is passed between two electrodes driven in to natural soil mass, the soil water will travel from the positive electrode(cathode) to the negative electrode(anode).
The still pipe or steel piling of excavation can serve as anode and water is pump out.

70. The causes of failure of foundations
The causes of failure of foundations may be summarized under the following heads : 1. Unequal settlement of the sub-soil. 2. Unequal settlement of masonry. 3. Sub-soil moisture movement. 4. Lateral pressure on the walls. 5. Lateral Movement of sub-soil. 6. Action of atmosphere.

71. Unequal settlement of sub-soil.
Unequal settlement of the sub-soil may lead to cracks in the structural components.
Unequal settlement of sub-soil may be due to
(i) Non-uniform nature of sub-soil throughout the foundation
(ii) Unequal load distribution of the soil strata, and
(iii) Eccentric loading.
The failures of foundation due to unequal settlement can be restricted by :
(i) Resting the foundation on rigid strata, such as rock or hard moorum,
(ii) Proper design of the base of footing, so that it can resist cracking,
(iii) Limiting the pressure in the soil, and
(iv)Avoiding eccentric loading

72. 2. Unequal settlement of masonry.
Foundation includes the portion of the structure which is below ground level.
This portion of masonry, situated between the ground level and concrete footing(base) has mortar joints which may either shrink or compress, leading to unequal settlement of masonry. Due to this, the superstructure will also have cracks.
This could be restricted by
(i) using mortar of proper strength,
(ii) using thin mortar joints,
(iii) restricting the height of masonry to 1 m per day if lime mortar is used and 1.5 m per day if cement mortar is used, and
(iv) properly watering the masonry.

73. 3. Sub-soil moisture movement.
This is one of the major causes of failures of footings on cohesive soil, where the sub-soil water level fluctuates.
When water table drops down, shrinkage of sub-soil takes place.
Due to this, there is lack of sub-soil support to the footings which crack, resulting in the cracks in the building.
During upward movement of moisture, the soil (specially if it is expansive) swells resulting in high swelling pressure.
If the foundation and superstructure is unable to resist the swelling pressure, cracks are induced.

74. 4. Lateral pressure on the walls.
The walls transmitting the load to the foundation may be subjected to lateral pressure from a pitched roof or an arch or wind action.
Due to this, the foundation will be subjected to a moment (or resultant eccentric load).
If the foundation has not been designed for such a situation, it may fail by either overturning or by generation of tensile stresses on one side and high compressive stresses on the other side of the footing.

75. Lateral Movement of sub-soil 
 This is applicable to very soft soil which are liable to move out laterally under vertical loads, specially at locations where the ground is sloping.
Such a situation may also arise in granular soils where a big pit is excavated for foundation.
Due to such movement, excessive settlements take place, or the structure may even collapse.
If such a situation avoided, sheet piles should be driven to prevent the lateral movement or escape of the soil. 

76.  Atmospheric action. 
The behavior of foundation may be adversely affected due to atmospheric agents such as sun, wind, and rains.
If the depth of foundation is shallow, moisture movements due to rains or drought may cause trouble.
If  the building lies in a low lying area, foundation may even be scoured.

77. Unequal settlement of subsoil

79. Lateral Movement of sub-soil

80. Lateral pressure on the walls.

81. Low lying area

82. Foundations on Black Cotton Soil
Black cotton soils and other expansive soils have typical characteristics of shrinkage and swelling due to moisture movement through them.
When moisture enter between the soil particles under some hydrostatic pressure, the particles separate out, resulting in increase in the volume.
This increase in volume is commonly known as swelling. If this swelling is checked or restricted high swelling pressure, acting in the upward direction, will be induced.
This would result in several cracks in the walls and may some times damage the structural such as lintels, beams, slabs etc.
During summer season, moisture moves out of the soil and consequently, the soil shrinks.
Shrinkage cracks are formed on the ground surface. These shrinkage cracks some times also known as tension cracks, may be 10 to 15 cm wide on the ground surface.
Black cotton soils and other expansive soils are dangerous due to their shrinkage and swelling characteristics.
In addition, these soils have very poor bearing capacity, ranging from 5 t/m2 to 10 t/m2.

83. For designing footings on these soils, the following points should be kept in mind:
1. The safe bearing capacity should be properly determined, taking into account the effect of sustained loading. The bearing capacity of these soils may be limited to 5 to 10 t/m The foundation should be taken at least 50 cm lower than the depth of moisture movement Where this soil occurs only in top layer, and where the thickness of this layer does not exceed 1 to 1.5 m, the entire layer of black cotton soil should be removed, and the foundation should be laid on non-shrinkable non- expansive soil Where the soil is highly expansive, it is very essential to have minimum contact between the soil and the footing. This can be best achieved by transmitting the loads through deep piles. 6. Where the bearing capacity of soil is poor, or soil is very soft, the bed of the foundation trench should be made firm or hard by ramming mooram.

84. Types of foundation in black cotton soils
Types of foundation in black cotton soils. Foundation in black cotton soils may be of the following types: 1. Strip foundation.  For medium loads, strip foundation may be provided, along with special design features.   2. Pier foundation  Piers are dug at regular interval and filled with cement concrete. The piers may rest on good bearing strata.   3. Under-reamed pile foundation. An under-reamed pile is a pile of shallow depth (1 to 6 m) having one bulb at its lower end.

85. Under-reamed Pile Foundation
Under-reamed piles are bored cast-in-situ concrete piles having bulk shaped enlargement near base.
These piles are commonly recommended for providing safe and economical foundations in expansive soils such as black cotton soil having poor bearing capacity.
In these type of foundation the structure is anchored to the ground at a depth where ground movement due to changes in moisture content negligible.
A pile having one bulk is known as single under-reamed pile. It is seen that the load bearing capacity of the pile can be increased by increasing the number of bulk at the base.
In such a case the pile is named as multi-under-reamed pile. The increase in the bearing capacity of the pile can also be achieved by increasing the diameter and the length of the pile.

86. The method of construction of under-reamed pile is very simple
 The method of construction of under-reamed pile is very simple. The holes for casting piles in the ground may be bored by using hand augers.
After boring is carried out at the required depth, the base of the bore hole is enlarged in the form of a bulb near its base by use of a tool, known under-reamer.
After the pile holes are ready for concreting, reinforcement cage are lowered in the holes and concrete is poured.
The piles should be cast at least 200 to 400 mm above the cut-off level. Later on, when the concrete is hardened, the extra length of each pile is broken and the pile top is brought to the desired level.   
Thus, besides relative saving in direct cost (when compared with conventional isolated footings) it is possible to have overall saving in time of completion of a work by adopting under-reamed piles.

88. A load-bearing wall
A load-bearing wall or bearing wall is a wall that bears a load resting upon it and transferred to a foundation structure.
The materials most often used to construct load-bearing walls are concrete block or brick.
Depending on the type of building and the number of floors, load-bearing walls are gauged to the appropriate thickness.
In housing, load-bearing walls are most common in the light construction method known as "platform framing”.

90. A partition wall
A partition wall is a wall that separates rooms or divides a room. Partition walls are usually not load-bearing.
Partition walls are constructed of many materials, including steel panels, bricks, blocks of clay,  concrete or glass blocks.
Some partition walls are made of sheet glass. Glass partition walls are a series of individual glass panels mounted in wood or metal framing.
A timber partition consists of a wooden framework, supported on the floor or by side walls.
Partition walls constructed from fiber cement sheeting are popular as bases for tiling in kitchens or in wet areas like bathrooms.
Plain or reinforced partition walls may also be constructed from concrete, including pre-cast concrete blocks.

94. HDPE wall
It is high density polyethylene (HDPE) one of the most chemically inert plastics.
It is resistant to chemical attack and corrosion, abrasion, and scratching.
Its superior in strength-to-weight ratio and flexible, it will support high live loads.
HDPE material is approximately 30 times lighter than reinforced concrete, making it easier to load, transport, handle and install.
The result is an increase in installation efficiency and a decrease in machinery and labor costs.

96. Methods to determine the bearing capacity of soil
The bearing capacity of soil can be determined by the following method:
Analytical method
Plate load test on the soil
Penetration test
Presumptive bearing capacity values from codes.

97. Plate load test
Plate load test is a field test to determine the ultimate bearing capacity of soil and probable settlement under a given loading.
The test essentially consists of a rigid plate at the foundation level and determining the settlement corresponding to each load increment.
The ultimate bearing capacity is then taken as the load at which the plate start sinking at a rapid rate.
The bearing plate is square of minimum recommended size 30 cm square and maximum 75 cm square.
The test pit width is made five times the width of plate(Bp). At the centre of the pit a small square hole is dug whose size is equal to size of plate.
The depth Dp of the hole should be such the that
Dp/Bp= foundation depth /foundation width

98. The loading to the test plate may be applied with help of a hydraulic jack.
The reaction of the hydraulic jack may be applied by gravity loading platform method.
In case of gravity loading platform method a platform is constructed over a vertical column resting on test plate and loading is done with help of sand bags, stones or concrete block.
The general arrangement of test set up for this method as shown in fig.
When load is applied to the test plate, it sink or settle. The settlement of plate is measured by the sensitive dial gauge.
For square plate two dial gauge are used.
As the plate settles, the ram of the dial gauge moves down and settlement is recorded.