diploma(civil) sem i boce_unit 3_building construction a
TRANSCRIPT
Diploma 1st Sem.
CIVIL
Building construction
Unite -3
Construction : Object created by constructing works, connected to ground,
performed from building products with common installations and
equipment, or integrated complex with facility or equipment as
well as technical - technological units or solo installations
connected to the ground. Or units connected to the ground but was
not made by construction works, if they change the purpose of the
land
Construction works :Performing constructional and other works (preparation, land, and
structural, installation, finishing and mounting of construction
products, plant or equipment) with which new buildings are built,
existing buildings are reconstructed, removed or maintained.
Constructing/Building:Means the process of designing,
constructing, usage and removal of the construction (building),
everything that is related to the constructing of the new buildings
can be applied in an appropiate way to reconstructing, maintance
and removal of the old buildings.
Construction site :Is a place,land or buildings (including
other areas that are temporarily occupied ) needed to execute the
construction works or the application of appropriate building
technology and security, on which to build, reconstruct, remove or
perform maintenance work building
Basic information to be collected are the
following:•technical-economic documentation of agreed work
•geographic and topographic conditions,
•meteorological and climatic conditions,
•geological and geotechnical conditions,
•hydrological conditions,
•ability to supply water, energy, etc.
•ability to supply material
•traffic, and conditions for delivery of materials, machinery, etc.
•opportunity for employment of labor force,
•property-legal relations,
•capacity of eventual subcontractors, suppliers, transportation
•companies,
•cost of resources to be used in the region in which to build, etc.
Site geography
• The exact geographical location of site,
• The nearest villages, centers of possible supply (constructionmaterials, handicraft workshops and repair shops, banks, postoffices, the building materials industry, quarries, gravel pits, desire.stations, ports, airports, pumps for liquid fuels, etc.)
• Economic description of cities, towns and other centers thatgravitate future construction, as documentation and backgroundshould submit: geographical maps and distances specified in relationto the site.
• Configuration of site has a big influence on the organization of thesite, or the disposition of various plants, design and development ofaccess roads, the internal communication at the site, the interiorhorizontal and vertical transport to the site and the whole works.
• Since the topography of ground depends on what will be applied tothe disposition of the site, which transport vehicles to use and howmuch transportation will cost.
Geological and geotechnical conditions
• When performing work on the building below the ground surfaceoccurs some problems related to groundwater (groundwaterelevation, vibration levels at various time periods, the strength ofunderground springs, etc.).
• Geological complex of ground, geomechanical and geotechnicalproperties of soil layers on the basis of appropriate tests, andgeological sections, geological map of the area generally shouldexist within the architectural- constructive phase of the project ofthe building, but contractor has all these elements to check beforebuilding.
• Determining the existence of groundwater, and their regime is ofgreat importance to the process of organizing works at zero cyclefacilities, as well as for predicting the equipment and installationsfor water pumping, fencing construction pit, concreting underwater, etc., which has great importance for, among other things,calculating and determining the cost of these works.
Meteorological and climatic conditions
Climatic conditions at the site are reflected in two ways:
• the creation of special conditions for life and work, or thehygienic and technical conditions, and the impact on theorganization and the construction technique.
• The human activity, climate has a direct effect especially whenthe works are carried out in the open. It has an impact on theperformance of workers and the effect of work generally.Unfavorable climatic conditions create special, difficult livingand working conditions of workers on site and reflect on the stateof health, and should be anticipated and calculate all necessarysafeguards for the health and maintaining good workingcondition of workers.
Meteorological and climatic conditions
• Climatic conditions are decisive for the annual fund of working
time, it is essential that information about climate and weather
conditions to be collected for a longer period of observation.
• Such information may be obtained from Hydro-Meteorological
Institute. data on rainfall and its distribution throughout the year,
with rainfall greater than 1 mm and 10 mm, as well as data on
relative humidity. on temperature, average annual, highest and
lowest, and the number of days with temperatures below 0 C or
lower than -5 C. information about the dominant winds, their
direction, intensity and duration. Strong winds can cause major
problems at work and in certain areas and to stop work
completely. Strong winds have an influence on the stability of the
scaffolding, formwork and roof, high pumps, etc.
Meteorological and climatic conditions
• Climatic conditions are decisive for the annual fund of working
time, it is essential that information about climate and weather
conditions to be collected for a longer period of observation.
• Such information may be obtained from Hydro-Meteorological
Institute. data on rainfall and its distribution throughout the year,
with rainfall greater than 1 mm and 10 mm, as well as data on
relative humidity. on temperature, average annual, highest and
lowest, and the number of days with temperatures below 0 C or
lower than -5 C. information about the dominant winds, their
direction, intensity and duration. Strong winds can cause major
problems at work and in certain areas and to stop work
completely. Strong winds have an influence on the stability of the
scaffolding, formwork and roof, high pumps, etc.
Site hydrology
• When it comes to the performance of buildings in the vicinity of
surface water, rivers, lakes, canals, must be familiar with the
water regime because it has a direct impact on the groundwater
regime.
• Based on the collected data should find the optimal technological
solution and make a study of evacuation from the building of
underground water tanks - wide excavation
Site organization – phase 1
• In the first phase of works is formed and performed:
– Traffic and site access
– Fence site and input (s)
– Earthworks on the site, digging pits
– Building site road (part of)
– Interim and secondary buildings on the site (part of)
– Energy and installation needed on site (part of)
Classification of buildingsNational building classification –national building code(NBC)
NO GROUP TYPE OF BUILDINGS
1 A RESIDENTIOL
A-1 lodging house
A-2 Family private dwelling
A-3 dormitories
A-4 apartments
A-5 hotels
2 B EDUCATIONAL
3 C INSTITUTIONAL
C-1 hospital
C-2 Penal institution
4 D ASSEMBLY BUILDINGS
5 E BUSINESS BUILDINGS
6 F MERCANTIALE BUILDING
NO GROU
P
TYPE OF BUILDINGS
7 G INDUSTRIYAL BUILDINGS
8 H STORAGE BUILDINGS
Classification OF building STRUCTURE
1. LOAD BEARING
STRUCTURE
these type of structure adopted
at places, where hard strata
available at shallow depths.
the load transfer to slab or roof
and floors are transmitted
through wall as firm soil.
upper story wall thickness less
then lower story
reduces building carpet area
2-3 story constructed these thye
structure
RCC FRAMED
STRUCTURES
• they are consist of a cross-
beams main beams, columns ,
plinth, footings
• there are all element rigid-joins
constructed .
• Its subjected to external loads,
• Compresive ,tensile ,torsion
DESIGN LOAD
1. DEAD LOAD
it consists of self weight of different parts of the
building like floor ,roof, walls, plaster, door, windows.
unit weight KN/m3
RCC- 25
PCC- 24
2. LIVE LOAD
live load consists of moving or variable loads due to
people or occupants their furniture ,temporary story,
machinery.
DESIGN LOAD
3. WIND LOADS
P=K.V2 p=wind pressure
k= coefficient. of size of structure
v= wind velocity
4. EARTHQUAKE LOADS
acts in horizontal direction .
earthquake force =m.∞
m= w/g
M=mass of buildings G=gravitational acceleration
∞= acceleration of earthquake
Different type of foundation
FOUNDATION
shallow foundation deep foundation
D<B D>B
spread pile
Combined coffer dams
Strap
Raft
grillage
Component Parts of a Building
The basic requirements a building should satisfy in design
and performance are:
•It must be strong enough to withstand the loads coming on
it including the self-weight, live load, wind load and
earthquake load.
•It must not deflect under the loads.
•It must give comfort and convenience to the inhabitants.
BUILDING
COMPONENTS
A building broadly consists of three
parts:
•Foundation
•Plinth
•Superstructure
1 Foundation•The foundation is the most critical part of any structure and most of
the failures are probably due to faulty foundations.
•Hence, it is highly essential to secure good foundation to maintain
the stability of the structure.
•A good foundation must remain in position without sliding,
bending, overturning or failing in any other manner.
The foundation of any structure should
be laid much below the surface of the
ground in order to attain the following:
•To secure a good natural bed.
•To protect the foundation courses from
atmospheric influences.
•To increase the stability of the structure
against overturning due to wind uplift.
The primary function of the foundation is to transmit the anticipated
loads safely to the soil below.
The foundation in a building structure is supposed to satisfy the
following basic requirements in their design and construction:
•To distribute the total load coming on the structure over a large
bearing area so as to prevent it from any movement.
•To load the bearing surface or area at a uniform rate so as to prevent it
from any movement.
•To prevent the lateral escape or movement of the supporting material
or alternatively to ensure the stability of the structure against sliding.
•To secure a level or firm natural bed upon which to lay the course of
masonry and also support the structure.
•To increase the stability of the structure as a whole to prevent it from
overturning or sliding against the disturbing forces such as wind, rain
and frost.
Plinth
This is the portion of the structure between the surface of the
surrounding ground and the surface of the floor immediately above
the ground. The thickness of the plinth wall depends upon the
weight of the superstructure and the width of the foundation
concrete. The minimum height of the plinth is usually kept as not
less than 4.5 cm.
The plinth wall should satisfy the following requirements in a
building structure in its design and construction:
•To transmit the load of the superstructure to the foundation.
•To act as a retaining wall so as to keep the filling in position below
the raised floor or the building.
•To protect the building from dampness or moisture.
•To enhance the architectural appearance of the building.
SuperstructureThe primary function of the wall is to enclose or divide space. Piers are
usually in the form of a thickened section of a wall, placed at intervals
along the wall to take concentrated vertical loads or to provide lateral
support to the wall.
A load-bearing wall should satisfy the following requirements:
•Strength: A wall should be strong enough to take up the loads safely.
The loads coming in the wall include its own weight, weight by
superimposed loads and bilateral pressures like wind.
•Stability: It should be stable against overturning by lateral forces and
buckling caused by excessive slenderness.
•Heat Insulation: It should be possible for walls to attain insulation
against heat.
•Sound Insulation: The walls should be made of such materials and by
such technique so as to insulate the building against sound.
•Privacy and Security: The walls should provide sufficient privacy and
afford security against theft.
FloorsThe main function of a floor is to provide support for occupants,
furniture and equipment of a building, and the function of providing
different floors is to divide the building into different levels for creating
more accommodation within the limited space .
A floor should satisfy the following requirements:
•Strength and Stability: All the floors, whether basement, ground or
upper should be strong enough to support the floor covering and other
superimposed loads.
•Durability and Damp Prevention: The floors provide a clean, smooth,
impervious, durable and wear-resisting surface.
•Heat Insulation: Insulation against heat should be provided in case of
ground and basement floors, especially when suspended and ventilated
timber floors are used.
•Sound Insulation and Fire Resistance: The insulation against sound and
fire should be provided in the case of upper floors as they act as
horizontal barriers for the passage of sound and fire in a vertical
direction.
Doors and windows
The main function of doors in a building is to serve as a connecting link
between internal parts and to allow free movement to the outside of the
building. Windows are generally provided for proper ventilation and lighting
and their number should be determined according to the requirements.
Doors and windows should satisfy the following requirements:
•Weather Resistance: They should be strong enough to resist the adverse effects
of weather.
•Sound and Thermal Insulation: They should be capable of being made air tight
to achieve insulation against sound and heat.
•Damp Prevention and Termite Prevention: They should not be affected by white
ants and the moisture penetration as this will reduce the strength and
durability.
•Fire Resistance and Durability: They should offer fire resistance and should be
durable.
•Privacy and Security: They should offer sufficient privacy without
inconvenience or trouble and security against theft.
Sills, lintels and weather shades
•Window sills are provided between the bottom of the window frame
and the wall below to protect the top of the wall from wear and tear.
The openings are provided in the wall of a building to accommodate
the doors and windows.
•The actual frame of a door or window is not strong enough to
support the weight of the wall above the opening and a separate
structural element is, therefore, introduced between the top of the
window frame and the wall coming over it.
•This is known as the lintel. Weather shades are generally combined
with lintels of windows to protect them from the weathering agencies.
Roofs
A roof is the uppermost part of a building whose main function is to enclose the
space and to protect the same from the effects of weather elements. A good roof is
just as essential as a safe foundation.
A roof should satisfy the following requirements:
•Strength and Stability: The roof structure should be strong and stable enough to take
up the anticipated loads safely.
•Weather Resistance: The roof covering should have adequate resistance to resist the
effects of weather elements.
•Heat Insulation: The roof should provide adequate insulation against heat.
•Sound Insulation: The roof should have adequate insulation against sound from
external sources.
•Fire Resistance: The roof should offer an adequate degree of fire resistance in order
to give protection against the spread of fire from any adjacent buildings and to
prevent early collapse of the roof. The form of construction should also be such that
the spread of fire from its source to other parts of the building by way of roof cannot
occur.
•Day Lighting: The roof provides daylight in buildings with large floor area.
Steps and stairsA step usually consists of a tread and riser supported by strings.
A stair is a structure consisting of a number of steps leading from one
floor to another.
Steps and stairs should satisfy the following requirements:
•Strength and Stability: The stairs should be designed like floors such
that they are strong and stable enough to carry the anticipated loads
safely due to the weight of the people using them and also the weight
of the furniture or equipment being carried up or down through them.
•Sound Insulation: The stairs should have adequate insulation against
sound from external sources.
•Weather Resistance: The stairs if exposed to open air should offer
sufficient resistance to weather elements such as rain and heat.
•Comfort: The proper design of steps and proper location of stairs in a
building offer several advantages such as comfort and efficiency in
vertical movement, natural light and ventilation and safety in
emergency.
Finishes for walls
Finishes of several types such as pointing, plastering, painting
and distempering and decorative colour washing are applied on
the walls.
The main functions of these finishes are as follows:
•They protect the structure, particularly the exposed surfaces,
from the effects of weather.
•They provide a true, even and smooth finished surface and
also improve the aesthetic appearance of the structure as a
whole.
They cover up the unsound and porous materials used in the
construction
Masonry is generally a highly durable form of construction.
However, the materials used, the quality of the mortar and
workmanship, and the pattern in which the units are assembled can
significantly affect the durability of the over all masonry
construction.
Masonry
GENERAL PRINCIPLES IN BRICK MASONRY•The bricks used should be hard, well burnt and tough with uniform
colour, shape and size.
•The bricks should be laid on their beds with the frogs pointing
upwards.
•The courses should be truly horizontal and should have truly vertical
joints.
•Use of brickbats should be avoided to the maximum possible extent.
•Generally, the height of the brick masonry construction in a day is
limited to 1.5 m.
•In order to ensure continuous bond, the walls should be stopped with
a toothed end at the end of each stage of construction.
•Finished brickwork should be cured for at least 2-3 weeks where
lime mortar is used and for 1-2 weeks where cement mortar is used.
TYPES OF BRICK MASONRY WALLS AND STRUCTURES
Spanning Openings in Brick Walls
• Brick walls must be supported above openings for windows or doors,
using reinforced concrete lintels, reinforced brick,or steel angles
• A corbel is an ancient structural device of limited spanning capability,
that may be used for small openings in brick walls, for beam brackets,
and for ornamental provisions.
• Arches can be used instead of lintels to span large openings in walls-
Different forms of arches can be built: Segmental Arch, Jack Arch,
Tudor Arch, Elliptical Arch, Roman Arch (cylindrical shape), Goethic
Arch, Parabolic - Arch Terminologies: Intados, Extrados, Soffit,
Spring line, Skewback, Crown, Span, Rise
TYPES OF BRICK MASONRY WALLS AND STRUCTURES
Reinforced Brick Masonry:
• A reinforced brick masonry wall in constructed with two wythes of
brick, 2” to 4” apart, placing the reinforced steel in the cavity and
filling the cavity with grout. Grout is a mixture of Portland cement,
aggregate and water. Grout must be filled enough to flow readily into
the narrow cavity and fill it completely - Two methods are used in
building reinforced brick walls: Low-lift method: Height of grout
filling is not more than 4 feet - Wythes are held together by galvanized
steel wire ties at 24” c/c horizontally and 16” c/c vertically - High-lift
method: Wall is grouted, one story at a time - Clean out holes are left
at the bottom to drive out the debri (from mortar in brick masonry)
down with water through the holes - Finally the clean out holes are
sealed with a brick and mortar joint
•Masonry is commonly used for the walls of buildings, retaining
walls and monuments.
•Brick and concrete block are the most common types of
masonry in use in industrialized nations and may be either
weight-bearing or a veneer.
•Concrete blocks, especially those with hollow cores, offer
various possibilities in masonry construction. They generally
provide great compressive strength, and are best suited to
structures with light transverse loading when the cores remain
unfilled. Filling some or all of the cores with concrete or
concrete with steel reinforcement (typically rebar) offers much
greater tensile and lateral strength to structures
Applications
•Brick floor.
• Earth floor.
• Cement concrete floor.
• Mosaic floor.
• Tile floor.
• Marble floor.
• Wooden floor.
TYPES OF FLOORS
FLOORING
MATERIALS FOR FLOORING
•The materials used for Ground floor
•construction are:
•Stones.
• Bricks.
• Concrete.
• Marble.
•Chips.
• Asphalt.
FACTORS AFFECTING SELECTION OF FLOORS
1- INITIAL COST
• The cost of floor covering is the most important thing.
• The expensive types of floor coverings are marble and teerrazzo (chips).
• Tiles and asphalt are less expensive whereas concrete and brick are the cheapest and are commonly used.
2- APPEARANCE
• Co lour, texture and architectural beauty are the factors taken into consideration.
3- DURABILITY
• Resistance to wear and tear is an important factor for a floor covering.
• Resistance to temperature changes, humidity, disintegration and decay has
alsoto be taken into account.
• Tiles, marble and concrete floor covering offer good resistance to these
factors. Wherever heavy floor traffic is not anticipated bricks and wood
blocks can be used.
4- CLEAN LINESS OF FLOOR
• A floor should be non absorbent and capable of being easily cleaned.
• All joints should be simple so that they can be made water tight as possible.
• Glass strips used for making panels, should not be more than 16 sq. ft. i.e.
(4`x4`).
5- DAMPNESS
• Moisture should not penetrate in the floor.
• They should be completely water tight.
• Wood, Rubber are not suitable in damp places, whereas tiles, bricks, concrete and Terrazzo is suitable for use on flooring which are subjected to dampness.
6- INDENTATIOIN
• Marks, depression due to furniture legs or ladies shoes should not make any impression on the floor.
7- NOISELESSNESS
• This is not an important factor for ground floor constructions,
but it should be noiseless when traveled over.
• Rubber coverings and cork covering are most suitable.
8- MAINTENANCE
• For keeping floor in perfect condition it is necessary to clean,
repair and apply any other treatment from time to time.
• Marble and concrete floors require less repair whereas wood
blocks, need frequent maintenance.
• Concrete surfaces can not be repaired easily while tiles can be
replaced quickly.
CONSTRUCTION OF FLOORS
1- BRICK FLOORING
• Brick flooring is commonly used.
• The filling over which this floor is to be laid should be well compacted.
• The level of the flooring being known, the filling is excavated the desired depth.
• Generally two types of beds are provided.
• In the first type, after excavation the surface is leveled and a layer of 3// sand is spread over which a course of bricks is laid.
• In the second type, a lean cement concrete (P.C.C), one part of cement, 6 parts of sand and 18 parts of aggregates of 10 to15 cms in thickness is laid on the compacted bed.
• Flat brick flooring is laid into1:6 C/S mortar over a bed of ¾ // thick cement sand mortar.
• Bricks on edge flooring are laid into1:6 C/S mortar over a bed of ¾ // thick C/S mortar.
2- CEMENT CONCRETE FLOORING
• This type of floors are most commonly used both in residential
and commercial buildings.
• The two components of a concrete floor are Base & Wearing
surface (top surface).
• The flooring can be constructed either monolithic or non-
monolithic.
• In monolithic floors, a base layer is laid and then immediately
a concrete topping is provided and in non-monolithic the
topping is laid after the base has set.
DISADVANTAGES OF MONOLITHIC
FLOORS• The topping is likely to get damaged due to subsequent
building operations.
• It is likely to develop hair-like cracks on account of small
settlements which may occur in the base course immediately
after it is laid.
• When the surface of the topping gets damaged, it is very
difficult to repair it.
• The progress is slow since the topping can be laid only after the
base course has sufficiently set to allow the workmen to lay the
top layer.
CEMENT CONCRETE FLOOR
DETAILS• Topping is laid in panels over a base thickness which varies 1//
to 3//.
• If the thickness is 1-1/2// then it can be laid in single layer and
if it is exceeding then it is laid in double layer.
• To avoid cracks due to shrinkage, the area of a panel is
restricted to 4/ x 4/ (i.e. 16 sq. ft.).
3. MOSAIC OR TERRAZO FLOORING• The base for terrazzo floor is of plain cement concrete (1:2:4).
• The topping shall not be less than 3/8// thick and shall be laid with a bottom layer of cement concrete (1:2:4).
• The total thickness of topping of cement concrete should mot be less than 1-3/8//.
• Normally 2// thickness is used, 1-1/2// concrete (1:2:4) and ½// mosaic.
• The mosaic topping shall consist of one part of cement (including15% to30% marble powder) and two parts of marble chips.
• The mosaic topping shall be laid while the bottom concrete is still fresh preferably on the next day or after 24 hours to have better bond.
• The surface should be rough to get better bonding.
4. TILE FLOORING
• Tiles of various shapes, sizes, thicknesses, color and surface
finishes are manufactured for used as surface covering for
floors.
• Floorings tiles are set on the concrete base with mortar.
• Special bedding made up of asphalt or portland cement is
available for use over concrete base.
• The concrete bedding is generally 5// thick and is laid evenly
with a slight rough surface at the top.
• After a period of 2 to3 days, a mortar layers of 1:1 mix is
spread on the concrete bed and the tiles are set evenly with a
thin a thin paste of cement applied to their sides.
• They are slightly topped till the cement comes out through the
joints to the top surface.
• This extra cement is wiped off and the joints are cleaned.
• After2 to3 days, these joints are rubbed to chip off all the
projecting edges or surfaces.
• The whole surface is then polished with a very soft
carborundum stone.
• Finally the surface is washed with soap. If the tiles have glazed
surfaces then this rubbing process is not suitable.
5. GLASS FLOOR• Glass floors are used wherever it is desired to admit light into
the basements through the upper floor.
• The glass blocks are fitted within the frames of various
thicknesses to transmit light at an angle to the farther areas in a
room.
• Structural glass is available in the from of tiles or slabs and its
thickness ranges from 12 to 30 millimeters.
• The framework is spaced closed apart so the glass can
withstand loads coming over it. Glass flooring is not commonly
used.
6. ASPHALT FLOORING
• Asphalt mastic is a mixture of fine aggregates (sand), natural or
artificial asphalt and coarse aggregates.
• It can be mixed hot and laid in continuous sheets or pressed into
blocks which can be used as flooring.
• It can also be mixed with a mineral oil and asbestos and applied
cold.
• While heating, the asphalt is stirred thoroughly so that the layer at
the bottom may not get burnt, when the whole quantity is fused,
sand or aggregates equal to twice the volume of asphalt is added
gently and mixed thoroughly. This mixture is then ready for
laying.
7. WOODEN FLOORING• This type of floor construction is not extensively used but is
popular for special purpose floors, e.g. in auditorium, hospitals.
• Wooden flooring should have a concrete base or should rest on
joists spanning across walls which are constructed at suitable
interval.
• For the fixing of wooden floors on concrete slabs, longitudinal
railing strips are provided.
ROOFS
The covering provided over the top of an enclosure made for a
building to keep out the sun, rain, wind and to protect the
interior from exposure to the weather is known as roof.
• A roof usually consists of frame work provided with a suitable covering at its top.
• A good roof is as essential as a safe foundation of a building.
• Roofs must, therefore, be well designed and constructed to meet the requirements of different climates and covering materials locally available.
• The form of construction of a roof is governed by the plan of a building, span, the type of covering material locally available and the architectural appearance required.
• The roof covering to be provided should be economical and most suitable according to the nature of the building.
CLASSIFICAION
• Sloping, pent or pitched roofs
• Flat or terrace roofs
(Sloping roofs are suitable for the area where rainfall and snowfall are heavy, whereas, flat roofs are suitable for the area where rainfall is meager i.e. of low intensity, and there is no snowfall)
• Shelled roofs
• Domes
1. Shed Roof:- A slopping roof having slope only in one direction is called a Shed Roof. This is the simplest type of sloping roof and is used for smaller spans.
2. Gable Roof:- A sloping roof having slope in two directions is called a Gable Roof. This type of sloping roof is used for larger span.
3. Hipped Roof:- A sloping roof having slope in four directions is called Hipped Or Hip Roof. This type of sloping roof is mostly used for buildings in hilly area.
4. Gambrel Roof:- A sloping roof having slope in two directions with a break in the slope is known as Gambrel Roof. This type of sloping roof is mostly used for buildings in hilly area.
5. Mansord roof:- A sloping roof having slope in four
directions with a break in slope is known as Mansard
Roof
6. Saw tooth or north light roof:- A sloping roof
having glazing fixed on the steep sloping sides of the
roof is called Saw Tooth Or North Light Roof. This is
generally used in factories where more light is
required.
IMPORTANT TECHNICAL TERMSRidge:- The highest point or line of a sloping roof where the two
opposite slopes meet is known as ridge.
Ridge piece:- A horizontal piece of timber which runs the highest level (bridge) of a sloping roof is called ridge piece.
Eaves:- The lowest edges of the surfaces of a sloping roof are called eaves.
Eave’s board:- A wooden board fixed along the eaves at the end of common rafters is known as eaves board or facia board. Gutter is usually supported at eaves board.
Jack rafter:- The short common rafters which run from a hip rafter to the eave of a sloping roof are called jack rafters.
Common rafters:- The members supporting the battens or boardings under the covering of a sloping roof are known as common rafters.
Gable:- The end of a sloping roof finished in a vertical triangle is called gabled end or gable.
Barge:- The finished edge of slating or tiling over-hanging a gable wall is called barge.
Barge board:- Wooden planks fixed to the ends of the common rafters projecting beyond the gabled end of a sloping roof is called a barge board.
Purlins:- The wooden or steel members laid horizontally to support the common rafters of a sloping roof are called purlins.
Cleats:- The pieces of timber or angle-iron which are nailed or screwed (for timber), riveted or welded (for angle-iron) on the trusses, to support the purlins are known as cleats.
Battens:- The pieces of wood which are directly nailed to the common rafters are called battens. The roof coverings are directly laid over battens.
Pitch:- The inclination of the side of a slopping roof to the horizontal surface is called pitch of the roof. It is usually expressed as the ratio of the rise to the span or in degrees.
Truss:- A frame work of members arranged in triangles is called a truss.
• Reference Books:
1) Elements of civil engineering by Rakesh Ranjan
2) Elements of civil engineering by B.C.Punamia
3) Basic Civil Engineering by L.G.Kulkarni