Transcript Slide 1

WALL
Wall
•Wall is a continuous, usually vertical structure, thin in proportion to its length
and height, built to provide shelter as an external wall or divide buildings into
rooms or compartments as an internal wall
•Prime function of an external wall is to provide shelter against wind, rain and
the daily and seasonal variations of outside temperature normal to its location,
for reasonable indoor comfort.
Functional Requirements
•Strength and stability
•Resistance to weather and ground moisture
•Durability and freedom from maintenance
•Fire safety
•Resistance to passage of heat
•Resistance to airborne and impact sound
•Security
Strength and stability
•The strength of the materials used in wall
construction is determined by the strength of a
material in resisting compressive and tensile stress,
and the way in which the materials are put
together.
•The stability of wall may be affected by
foundation movement, eccentric loads, lateral
forces(wind) and expansion due to temperature
and moisture changes.
Resistance to weather and ground moisture
•Moisture which includes water vapour and liquid water
may penetrate a wall by absorption of water from the
ground that is in contact with foundation walls or through
rain falling on the wall.
•To prevent water, the impermeable layer (damp proof
course) is built in about 150mm above ground level.
Durability and freedom from maintenance
Durability of a wall is indicated by the frequency and extent of the work necessary
to maintain minimum functional requirements and an acceptable appearance.
Fire safety
The Building Regulations has set the standards for means of escape, limitation
of spread of fire and containment of fire.
The requirements of Part B of Schedule 1 to the Building Regulations are
concerned to:Provide adequate means of escape
Limit internal fire spread (linings)
Limit internal fire spread (structure)
Limit external fire spread
Provide access and facilities for the fire services
Resistance to passage of heat
•The interior of buildings is heated by :•Conduction-the transfer of heat from heaters and radiators to air,
•Convection-the circulation of heated air
•Radiation-the radiation of energy from heaters and radiators to surrounding colder
surfaces.
•This internal heat is transferred through colder enclosing walls, roofs and floors by
conduction, convection and radiation to colder outside air.
•For insulation against loss of heat, lightweight materials with low conductivity are
more effective than dense materials with high conductivity.
•Dense materials have better thermal storage capacity than lightweight materials.
Resistance to airborne and impact sound
•Sound is transmitted as airborne sound and impact sound
•Airborne sound is generated as cyclical disturbances of
air that radiate from the source of the sound with
diminishing intensity. Example: radio
•The vibrations in the air caused by the sound source will
set up vibrations in enclosing walls and floors which will
cause vibrations of air on the opposite side of walls and
floors.
•Impact sound is caused by contact with a surface.
Example, the slamming of a door or footsteps on a floor
which set up vibrations in walls and floors that in turn
cause vibrations of air around them that are heard as
sound.
•Effective insulation against airborne sound is a dense
material barrier such as a solid wall, which absorbs the
energy of the airborne sound waves.
Walls may be classified as solid or framed.
Solid wall (masonry wall)
• constructed using brick or blocks of stone, or concrete laid
in mortar with the block laid to overlap bonding
(monolith)
• Solid wall of bricks or blocks may be termed as block
wall(masonry)
• Continuous solid wall of concrete called as monolithic
wall.
Frame wall
•constructed from a frame of small sections of timber,
concrete or metal joined together to provide strength and
rigidity over both faces or between the members of the
frame.
•Each of the two types of wall may serve as internal or
external wall and as load bearing or non-load bearing wall.
External Wall
An outer wall of a building not
being partition and also means a
wall next to an interior open space
of any building
Internal Wall
Inner part of wall in
building, or any wall that
does not have a separation
function between dwellings
External wall
Superstructural
(above ground)
Curtain wall & Cavity wall
Substructural
(under ground)
Retaining wall
-Gravity wall
-Piling wall
-Cantilever
-Anchored wall
Superstructure (above ground)
Curtain wall
•A curtain wall system is an outer covering
of a building in which the outer walls are
non-structural, but merely keep the weather
out and the occupants in.
•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 weight forces.
Wall and window
system (cavity wall)
•Cavity walls consist of two 'skins'
separated by a hollow space (cavity). The
skins are commonly masonry such as brick
or concrete block. Masonry is an
absorbent material, and therefore will
slowly draw rainwater or even humidity
into the wall.
Substructural (under ground)
Retaining wall
•Retaining walls are structures designed to restrain soil to unnatural slopes.
•The structure designed and constructed to resist the lateral pressure of soil
when there is a desired change in ground elevation that exceeds the angle of
repose of the soil
-Gravity wall
-Piling wall
-Cantilever
-Anchored wall
Substructural (under ground)
Gravity wall -standard wall type
that holds the earth mainly through
its own weight. Can pivot and topple
easily, as the internal leverage of the
earth pressure is high.
Piling wall –Using long piles, this wall
is fixed by soil on both sides of its
lower length. If the piles themselves
can resist the bending forces, thick
wall can take high loads.
Cantilever wall –uses the same
earth pressure trying to topple it to
stabilize itself with a second lever
arm.
Anchored wall –this wall keeps itself
from toppling by having cables
driven into soil or rock, fixed by
expanding anchors(can be combined
with other types of wall)
Internal wall
Structural
Shear Wall & Core wall
Non-structural
Partition Wall
Structural Internal Wall : Shear Wall
Shear wall is a wall composed of braced panels (also known as shear panels) to
counter the effects of lateral load acting on a structure.
So, in order to prevent any deformation which
may occur in wooden buildings, it is important
to either (1) attach "diagonal bracings" between
two columns, or (2) attach "structural wall
boards" with screws to frames.
Functions of shear wall:Strength
•Shear walls must provide the necessary lateral strength to resist horizontal
earthquake forces.
Stiffness
•Shear walls also provide lateral stiffness to prevent the roof or floor above
from excessive side-sway.
•Stiffness will prevent floor and roof framing members from moving off their
supports.
•Also, buildings that are sufficiently stiff will usually suffer less nonstructural
damage.
Structural internal wall : Core Wall
•A "core wall" is a temporary reinforced-concrete
structure located in the center of a building designed to
absorb the potential horizontal forces generated by an
earthquake.
•The core acts as a cantilever beam coming from the
basement and it stabilizes the building mainly with regard
to horizontal forces like wind and earthquake.
• A "load transferring frame," is set up in a column in four
corners where the core
wall is
enclosed.
•If an earthquake occurs, the core wall and the aboveground part of the steel frame combine to provide
earthquake resistance. The system also includes safety
systems such as a seismograph and an earthquake
warning system.
NON STRUCTURAL INTERNAL WALL
PARTITION WALL
•A partition wall is a wall for the purpose of separating rooms, or dividing a room.
Partition walls are usually not load-bearing
•Partition walls may be constructed with bricks or blocks from clay,
reinforced, or hollow. Glass blocks may also be used.
concrete,
•Wall partitions are constructed either hung from the ceiling or fixed into the ground.
The panels are inserted into the tracking and fixed.
END