Basic component of buildings

BASIC COMPONENT OF BUILDINGS
By: Ar. Sanjib Sengupta
September 2016

WHAT IS BUILDING
Any structure for whatsoever purpose and of
whatsoever materials constructed and every part
thereof whether used as human habitation or not and
includes foundation, plinth, walls, floors, roofs,
chimneys, plumbing and building services, fixed
platforms, verandah, balcony, cornice or projection,
part of a building or anything affixed thereto or any
wall enclosing or intended to enclose any land or space
and signs and outdoor display structures. tents/
shamianahs / pandals, tarpaulin shelters, etc., erected
for temporary and ceremonial occasions shall
not be considered as building.

WHAT IS BUILDING
However here we will talk about a structure with a
roof and walls including all attached apparatus,
equipment, and fixtures standing more or less
permanently in one place. Buildings come in a
variety of sizes, shapes and functions, and have
been adapted throughout history for a wide
number of factors, from building materials
available, to weather conditions, to land prices,
ground conditions, specific uses and aesthetic
reasons.

PURPOSE OF A BUILDING.
Buildings serve several needs of society
primarily as shelter from weather, security,
living space, privacy, to store belongings, and
to comfortably live and work. A building as a
shelter represents a physical division of the
human habitat (a place of comfort and
safety).

TYPE OF BUILDINGS
Residential house, school, hospital, or factory etc.
Buildings may be load bearing masonry buildings
or RCC framed structure building.
Load Bearing Masonry Building RCC framed Structure Building

1. Sub-Structure or Foundation:- The
lower portion of the building, which
is located below the ground/soil , is
called foundation. Foundation, which
is in direct contact with ground in
depth, transmits the loads of the
super-structure to the supporting soil.
Floors below ground/soil are called
basement, being below ground,
wherever constructed are also part of
Sub-Structure. However Padstone
foundation is always over ground and
normally found in hill area.
2. Super Structure:-The upper
part/portion of the building above
ground level with roof and walls
including all attached apparatus,
equipment, and fixtures
BASIC COMPONENT OF A BUILDING
All Buildings which are built on ground are two primary basic component

WHAT ARE THE LOADS OF SUPER STRUCTURE
1.Dead loads:-Are permanent or stationary loads which are transferred to
structure throughout the life span. Dead load is primarily due to self-weight of
structural members like walls, roofs, permanent partition walls and other fixed
components of building, fixed permanent equipment, furniture and weight of
different materials etc.
2. Live loads:-Are either movable or moving loads without any acceleration or
impact. Live loads that do, or can, change over time. Live loads include any
temporary or transient forces that act on a building or structural element.
Typically, they include people, movable partitions and furniture, vehicles, and
almost everything else that can be moved throughout a building.
3.Impact Loads:-Caused by vibration or impact or acceleration. Thus, impact
load is equal to imposed load incremented by some percentage called impact
factor or impact allowance depending upon the intensity of impact.
4. Environmental loads:-Are loads that are created naturally by the environment
and include wind, snow, seismic, and lateral soil pressures.

TYPE OF SUB-STRUCTURE/FOUNDATION
Foundations are divided into two categories:
1.Shallow foundations:- Shallow foundations can
be made in depths of as little as 3ft (1m) and are
used for small, light buildings.
2.Deep foundations:- Deep foundations can be
made at depths of 60 - 200ft (20 - 65m) and are for
large, heavy buildings

SHALLOW FOUNDATIONS
These are also called spread footings or open footings. The 'open' refers to the
fact that the foundations are made by first excavating all the earth till the bottom
of the footing, and then constructing the footing. During the early stages of work,
the entire footing is visible to the eye, and is therefore called an open foundation.
The idea is that each footing takes the concentrated load of the column and
spreads it out over a large area, so that the actual weight on the soil does not
exceed the safe bearing capacity of the soil. There are several kinds of shallow
footings: i) Individual footings/Isolated Footing, ii) Strip Footings/Spread
Footing, iii), Pad Foundation, iv) Pad Stone Foundation v) Rubble Stone/trench
Foundation and vi) Raft Foundation. In cold climates, shallow foundations must
be protected from freezing. This is because water in the soil around the
foundation can freeze and expand, thereby damaging the foundation. These
foundations should be built below the frost line, which is the level in the ground
above which freezing occurs. If they cannot be built below the frost line, they
should be protected by insulation: normally a little heat from the building will
permeate into the soil and prevent freezing.

INDIVIDUAL FOOTING/ISOLATED FOOTING
Individual footings are one of the most simple and common types
of foundations. These are used when the load of the building is
carried by columns. Usually, each column will have its own
footing. The footing is just a square or rectangular pad of
concrete on which the column sits.

STRIP FOOTINGS/SPREAD FOOTINGS
Strip footings are commonly found in load-bearing masonry construction, and act as
a long strip that supports the weight of an entire wall. These are used where the
building loads are carried by entire walls rather than isolated columns, such as in
older buildings made of masonry. It is continuous foundation of which the length
considerably exceeds the breadth. The depth of a strip foundation must be equal to
or greater than the overall width of the wall. The principle design features of a
strip/spread foundation/footing are based on the fact that the load is transmitted at
45 degrees from the base of the wall to the soil. The key sizes of a strip foundation
for concrete cavity wall construction and timber frame cavity wall construction are
similar. The size and position of the strip is directly related to the overall width of
the wall. The width of the foundation must be three times the width of the supported
wall Strip foundations are used where the soil is of good bearing capacity.

PAD FOUNDATION
Pad foundations are generally rectangular
or square foundation to transfer load from
structure to the ground. These are provided
at shallow depth and are shallow
foundations.

PADSTONE FOUNDATION
Perhaps the simplest foundation is the Padstone,
a single stone which both spreads the weight on
the ground and raises the timber off the ground

RUBBLE STONE FOUNDATION
The rubble trench foundation, an ancient construction approach popularized
by architect Frank Lloyd Wright, is a type of foundation that uses loose
stone or rubble to minimize the use of concrete and improve drainage. It is
considered more environmental friendly than other types of foundation
because cement manufacturing requires the use of enormous amounts of
energy. However, some soil environments are not suitable for this kind of
foundation; particularly expansive or poor load-bearing (< 1 ton/sf) soils. A
rubble trench foundation with a concrete grade beam is not recommended
for earthquake prone areas.
Rubble trench Foundation Cross section view of
rubble trench foundation

RAFT OR MAT FOUNDATIONS
Raft Foundations, also called Mat Foundations, are most often used when
basements are to be constructed or where the soil is week or where columns are
closely spaced (which means that if individual footings are used, they may
touch each other.) so that building loads are spread over a large area. Mat
foundations are the types of foundation which are spread across the entire area
of the building to support heavy structural loads from columns and walls. The
use of mat foundation is for columns and walls foundations where the loads
from the structure on columns and walls are very high. This type of foundation
is used to prevent differential settlement of individual footings, thus designed
as a single mat (or combined footing) of all the load bearing elements of the
structure.

DEEP FOUNDATIONS
1. Pile Foundations:-
Pile foundation is a type of deep foundation which is
used to transfer heavy loads from the structure to a hard
rock strata much deep below the ground level. Pile
foundations are generally used for soils where soil
conditions near the ground surface is not suitable for
heavy loads. The depth of hard rock strata may be 5m to
50m (15 feet to 150 feet) deep from the ground surface.
The pile foundations resists the loads from structure by
skin friction and by end bearing. Pile foundations are
capable of taking higher loads than spread footings. Use
of pile foundations also prevents differential settlement
of foundations.

Pile Foundations( Cont.---)
A pile is basically a long cylinder of a strong material
such as concrete or wood that is pushed into the ground
so that structures can be supported on top of it.
Concrete Pile Wooden Pile

Pile foundations are used in the
following situations:
a) When there is a layer of weak soil
at the surface. This layer cannot
support the weight of the building,
so the loads of the building have to
bypass this layer and be transferred
to the layer of stronger soil or rock
that is below the weak layer.
b) When a building has very heavy,
concentrated loads, such as in a high
rise structure.
There are two types of pile
foundations, i) End bearing & ii)
Friction Pile, each of which works
in its own way.

End Bearing Piles:- In end bearing piles, the bottom end of the pile rests on a
layer of especially strong soil or rock. The load of the building is transferred
through the pile onto the strong layer. In a sense, this pile acts like a column. The
key principle is that the bottom end rests on the surface which is the intersection
of a weak and strong layer. The load therefore bypasses the weak layer and is
safely transferred to the strong layer.
Friction Piles:-Friction piles work on a different principle. The pile transfers the
load of the building to the soil across the full height of the pile, by friction. In
other words, the entire surface of the pile, which is cylindrical in shape, works to
transfer the forces to the soil.
To visualize how this works, imagine you are pushing a solid metal rod of say
4mm diameter into a tub of frozen ice cream. Once you have pushed it in, it is
strong enough to support some load. The greater the embedment depth in the ice
cream, the more load it can support. This is very similar to how a friction pile
works. In a friction pile, the amount of load a pile can support is directly
proportionate to its length. In practice, however, each pile resists load by a
combination of end bearing and friction.

The mono pile foundation is a
simple construction. The
foundation consists of a single,
generally large diameter steel
pile/structural element with a
diameter of between 3.5 and 4.5
meters embedded into the earth
to support all the loads (weight,
wind, etc.) of a large above-
surface structure. The pile is
driven some 10 to 20 meters into
the seabed depending on the type
of underground. This type of
foundation is normally used for
offshore construction
Monopile foundation

Drilled shafts is also a type of deep foundation
and has action similar to pile foundations
discussed above, but are high capacity cast-in-
situ foundations. It is also called as caissons. It
resists loads from structure through shaft
resistance, toe resistance and / or combination of
both of these. The construction of drilled shafts
or caissons are done using an auger. This
foundation can transfer column loads larger than
pile foundations. It is used where depth of hard
strata below ground level is location within 10m
to 100m (25 feet to 300 feet).Drilled shafts or
caisson foundation is not suitable when deep
deposits of soft clays and loose, water-bearing
granular soils exists. It is also not suitable for
soils where caving formations are difficult to
stabilize, soils made up of boulders, artesian
aquifer exists.
Drilled Shafts or Caisson Foundation

SUPER STRUCTURE
Generally consist of i) Plinth, ii) Plinth Beam, iii) DPC, iv)
Plinth protection v) Floors, vi) Column, vii) Walls, viii)
Openings Doors/Windows/Ventilators, ix) Sill, x) Lintel, xi)
Beam, xii) Roof. xiii) Parapet, xiv) Staircase, xv)Mumty,
xvi) Lift machine

Plinth
Plinth is a part of the super-structure, defined as the portion of the
structure between the surface of the surrounding ground and surface of
the floor, immediately above the ground. The distance between the
surface of the surrounding ground and surface of the floor, immediately
above the ground is called plinth height, which should be of minimum
450 mm, negotiable by steps or ramp. The level of the floor is usually
known as the plinth level. The built-up covered area measured at the
floor level is known as plinth area.

Plinth beam
Beam laid above the foundation i.e. at plinth level, and braces the plinth level is called
plinth beam. Plinth beam is an important part of a structure which transfer loads to the
adjacent columns. The void between the foundation and plinth level is filled with
compacted soil. Brick or stone masonry is usually constructed below the plinth beam.
This beam is normally provided in framed structure for proper framing of structure and
disbursing the live loads as well as dead loads of super structure. It is also known as a tie
beam and is made so that the columns do not split due to load coming from above. Some
times this beam known as plinth band is provided in load bearing masonry structure also.
In principle plinth (or tie) beams between pads are only required if-- i) Differential
settlement or rotation of individual pads (such as in poor ground conditions or big
differences in applied pressures between adjacent pads) is expected. ii) To maintain the
plinth plane proper ii) The beams are needed to support walls or floating ground floor
slabs. & iii) The foundations are at different levels- such as a building built on the side
of a hill.

Damp Proof Course i.e. DPC
A damp-proof course (DPC) is a barrier through the structure by
capillary action such as through a phenomenon known as rising damp.
Rising damp is the effect of water rising from the ground into property.
The damp proof course may be horizontal or vertical. Damp proofing
in construction is a type of moisture control applied to building walls
and floors to prevent moisture from passing into the interior spaces.. A
DPC layer is usually laid below all masonry walls, regardless if the
wall is a load bearing wall or a partition wall. For DPC above ground
level with wall thickness generally not exceeding 40cm, any one of the
type of materials mentioned below may be used. Cement concrete is
however commonly adopted material for DPC at plinth level, 38 to
50mm thick layer of cement concrete M15 (1:2:4 mix) serves the
purpose under normal conditions. An effective damp proofing material
should have the following properties;

Damp Proof Course i.e. DPC ( Cont.---)
• It should be impervious.
• It should be strong and durable, and should be capable of
withstanding both dead as well as live loads without damage.
• It should be dimensionally stable.
• It should be free from deliquescent salts like sulphates, chlorides
and nitrates.
The materials commonly used to check dampness can be divided into
the following three categories:
Flexible Materials: Materials like bitumen felts (which may be hessian
based or fibre/glass fibre based), plastic sheeting (polythene sheets)
etc.
Semi-rigid Materials: Materials like mastic, asphalt, or combination of
materials or layers.
Rigid Materials: Materials like first class bricks, stones, slate, cement
concrete etc.

Plinth protection
Plinth protection is the additional length or strengthening provided in the
lowest portion of a beam or the lower portion of a foundation/floor by
providing additional thickness/height. In short: plinth is base of structure, it
transmit weight of structure to the soil. The plinth usually rests directly on the
ground, the plinth exists to negotiate between a structure and the ground. Some
Soils has Chemicals inside and minerals that can deteriorate the strongest
reinforced Concrete structure, so a protection layer is a must to extend the age
of the structure. Many times plinth have to deal with external agencies like
water, roots of trees, termites, etc this can affects the life of plinth and makes it
weaker so it’s essential to protect plinth from such agencies, therefore plinth
protection is necessary

Floors
A floor is the walking surface of a room. The levels of a building are often
referred to as floors although a more proper term is story or storey. Floors
typically consist of a subfloor for support and a floor covering used to give a
good walking surface.

Column
A column or pillar is a vertical structural element that takes
the load of beam slab etc. and transfers the load to the earth
independently is called column. Columns are frequently
used to support beams or arches on which the upper parts of
walls or ceilings rest.

Walls
Walls are the vertical elements and fundamental part of the
superstructure of a building which enclose the space within
it and which may also divide that space. A wall is a structure
that defines an area, carries a load, provides shelter and
security. There are many kinds of walls: External walls,
Internal walls, partition walls Defensive walls in
fortification, Retaining walls, Boundary walls, Load bearing
walls, Non load bearing walls, Curtain walls etc.

Curtain wall:- Is a system for outer
covering of a building in which the outer
walls are non-structural, but merely keep
the weather out and the occupants in. The
curtain wall being non-structural it can
be made of a material other than
conventional brick and concrete. Curtain-
wall systems are typically designed with
extruded aluminum members infilled
with glass, which provides benefits such
as daylighting. However, parameters
related to solar gain control such as
thermal comfort and visual comfort are
more difficult to control when using
highly glazed curtain walls. Other
common infills include: stone veneer,
metal panels, louvers, and operable
windows or vents.
Walls(Cont.---)

Walls(Cont.---)
The curtain wall facade does not carry
any dead load from the building other
than its own dead load. The wall transfers
horizontal wind loads that are incident
upon it to the main building structure
through connections at floors or columns
of the building. A curtain wall is designed
to resist air and water infiltration, sway
induced by wind and seismic forces
acting on the building, and its own dead
load forces. Curtain walls, differ from
store-front systems, are designed to span
multiple floors, & take into consideration
design requirements such as: thermal
expansion & contraction; building sway
& movement; water diversion; thermal
efficiency for cost-effective heating,
cooling, and lighting in the building.

Openings
What does opening mean in a building. A gap, hole, breach, or aperture in the
wall of a building for ingress and egress and for admission of light and air.
Types of Openings in Buildings
1. Doors:-An openable barrier secured in an
opening left in a wall for the purpose of ingress
and egress to/from the structure. It basically
consists of two parts, namely, frame and shutter.
The door shutter is held in position by the door
frame which in turn is fixed in the opening of
the wall by some suitable means.
2. Windows:-: An opening especially in the wall
of a building for admission of light and air. It
also basically consists of two parts, namely,
frame and shutter. The window shutter is also
held in position by the door frame which in turn
is fixed in the opening of the wall by some
suitable means. Generally window bottom shall
have sill.
3. Ventilators:-An opening or aperture smaller
than window, in the wall and above lintel level
for ventilating a room or other space.

Window Sill:-
The horizontal member at the base of a
window opening. Window frame sits
on the window sill of the wall opening.
Lintel:- A structural horizontal block
that spans the space or opening
between two vertical supports and
serves to carry the weight of the wall
above it . A lintel can be a load-bearing
building component, a decorative
architectural element, a combined
ornamented structural item. It is often
found over portals, doors, windows &
fireplaces. A horizontal supporting
member, installed above an opening
such as a window or a door.

BEAM
A beam is a horizontal or inclined
structural element/member spanning a
distance between one or more supports,
and carrying vertical loads across
(transverse to) its longitudinal axis that
is capable of withstanding load primarily
by resisting against bending. A beam is a
laterally loaded member, whose cross-
sectional dimensions are small as
compared to its length. Six basic types of
beams are: (1) Fixed, (2) Simple
supported, (3) Continuous, supported at
more than two points, (4) Over hanging,
double over hanging, (5) Cantilever,
supported at one end with the other end
overhanging and free, (6) Truss.

BEAM (Cont.--)
The other types of beam are i.) Flat
beam—a beam whose width is larger than
depth. ii.) Upstand/inverted beam--a
beam that projects above floor level, iii.)
Concealed/Hidden beam is defined as the
beam whose depth is equal to the
thickness of the slab.
Truss:-essentially a triangulated system
of straight interconnected structural
elements. The most common use of it is
in buildings, where support to roofs, the
floors and internal loading such as
services and suspended ceilings, are
readily provided. The main reasons for
using trusses are:-i)Long span, ii)
Lightweight, iii) Reduced deflection
(compared to plain members),
Opportunity to support considerable
loads.
Upstand Beam
Flat Beam

Roof/Terrace
A roof is part of a building envelope. It
is the covering on the uppermost part
of a building or shelter which provides
protection from weather, notably rain,
snow, heat, wind and sunlight. The
characteristics of a roof are dependent
upon the purpose of the building that it
covers, the available roofing materials
and the local traditions of construction
and wider concepts of architectural
design and practice and may also be
governed by local or national
legislation. A roof may also provide
additional usable space, for
roof/terrace garden , installation of
water tank, solar panel/ heater etc.
Roof can be flat roof or slope roof.

PARAPET
Parapet is a barrier at the edge of a roof,
terrace, balcony, walkway or other structure.

STAIRCASE
A staircase/stairway is a construction
designed to bridge a large vertical
distance by dividing it into smaller
vertical distances, called steps. Stairs
may be straight, round, spiral, dog
legged or may consist of two or more
straight pieces connected at angles. In
buildings, stairs is a term applied to a
complete flight of steps between two
floors. A stair flight is a run of stairs or
steps between landings. A staircase or
stairway is one or more flights of stairs
leading from one floor to another, and
includes landings, newel posts,
handrails, balustrades and additional
parts. A stairwell is a compartment
/shaft extending vertically through a
building in which stairs are placed.

Mumty is a colloquial ward which denote the covering of stair well at
minimum 2.1 m above the last landing of the staircase at roof level.
MUMTY

A Lift machine room (sometimes known as elevator machine room or
lift motor room) is a room that house elevator drives and controllers.
This room projects above roof level.
Lift Machine Room

Basic component of buildings

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