building materials and construction

Building Materials&

Construstion

Prepared By:

Aakash SinghF.Y. (B.E. Mechanical)

Contents Building Materials

• Sand • Aggregates• Mortar• Concrete• Bitumen

Construction• Classification of Buildings• Types of Loads• Building Components, their functions and

nominal dimensions

Introduction to

Building Materials

Sand is an important building material which consists of small rounded or angular grains of silica (SiO2).It is formed by decomposition or disintegration of sand stone under action of weather such as wind, rains, frost, etc.Sand can be classified into three main types depending on the sources from which it is obtained :1. Pit Sand

It is obtained by digging pits in the soil and is excavated from a depth of about 1.2 m from ground level. This soil consists of sharp angular grains, which are free from silt, clay, etc. Clean pit sand forms an excellent material for mortars and concrete.

Sand

2. River Sand Widely used for all purposes and best sand for important work.Obtained from banks or beds of rivers and consists of fine rounded grains.It is almost white in colour.

3. Sea SandIt is obtained from sea shores.It have clean rounded light brown particles.It is available with bad salts and hence it is unsuitable for making mortar or concrete.It increases the setting time of cement, hence it avoided for engineering purposes.

Sand

Classification of Sand based on Particle size1. Gravely Sand : Sand passing through 7.620 mm size

sieve is called gravely sand.It is used for concrete work.

2. Coarse Sand : Sand particles passing through 3.175 mm sieve is termed as coarse sand.It is generally used for masonry work.

3. Medium Sand : Sand particles passing through 2.36 mm sieve is termed as Medium sand.It used for plastering.

4. Fine Sand : Sand particles passing through 1.5875 mm sieve is termed as fine sand.It is mainly use for plastering.

Sand

Properties of Good Sand

1. It should be clean and free from silt, clay and other injurious materials.

2. Chemically inert.3. Should have sharp angular grains.4. Size of grain should be between 4 to 6 mm.5. Should be strong and durable.

Uses of Sand

1. Making lime mortar.2. Making cement mortar.3. Making cement concrete4. Used for masonry work, plastering and pointing works.

Sand

Aggregates are the inert materials that are mixed in fixed proportions with a cementing material to produce concrete.It acts as fillers or volume increasing components and are responsible for strength, hardness and durability of concrete.

Aggregate

Classification of Aggregates

A. Based on Grain sizeBased on size of grains, it is classified into two types:1. Fine Aggregates : Materials which passes through BIS test

sieve No. 480 is termed as Fine aggregates.It have size less than 4.75 mm.

2. Coarse aggregates : Materials retained on BIS test device No. 480 is termed as Coarse aggregates.It have size more than 7.55 mm.

B. Based on Origin1. Natural Aggregates : Includes all fine coarse aggregates

which are available in almost ready to use form from natural sources. Sands from riverbed are its examples

2. Artificial Aggregate : It can be broken bricks or crushed air-cooled blast furnace slag.

Aggregate

C. Based on DensityNormal Aggregates : Gravels, sand and crushed stones are classes of normal aggregates. These gives concrete of standard strength and weighing around 2300-2500 kg/m3.High Density Aggregates : Barite is used as aggregates in standard proportions yield heavy concrete weighing above 4000 kg/m3.Light Weight Aggregates : Consists of natural and artificial materials of low density. Concretes with such aggregates usually weighs within a range of 350-750 kg/m3.

Aggregate

Uses of Aggregates

1. Generally used to make Concrete.2. Fine aggregates serve the purpose of filling all open spaces

in between coarse particles.3. Coarse aggregate acts as main load-bearing component of

concrete.4. Blast furnace slag is suitable aggregate to make light-weight

concrete.5. Aggregates are used as road metals, ballast for railway

sleepers, etc.

Aggregate

On surfaces of roofs whose positioning, shape and drainage systems are such as to make accumulation of rain water possible, the load due to the rain water is known as the Load due to rain.

Mortar

Classification of Mortars :

1. Lime Mortar In lime mortar, fat lime or hydraulic lime is used as the binding material.it consists of a mixture of lime and sand worked with water.

2. Cement MortarCement is used as a binding material. It consists of mixture of cement with sand in presence water.

3. Lime – Cement MortarTo improve quality of lime mortar, cement is added to it.It contains lime, cement, sand and water.

Mortar

4. Surkhi MortarPrepared by using fully surkhi instead of sand or by replacing half of sand in case of fat lime mortar.Ratio of lime to surkhi will depend on the nature of job where mortar is used.

5. Gypsum MortarIn theses mortars, gypsum cement are the binding materials.these are rarely used in tough construction and are used as plasters.

Mortar

Qualities of a good Mortar

1. Mortar mix should be easily mixable.2. Should set and harden quickly so that construction

could be done with speed.3. Should not develop any cracks on drying.4. Should be durable.5. Mortar should be capable of retaining sufficient water

during its application.6. Should be cheap and economical.

Mortar


Concrete


Bitumen

Introduction to

Construction

Classification of Buildings

Classification

of

Buildings

Classification of BuildingsBuildings are classified as follows :i. Based on occupancy, i.e. purpose served by buildingsii. Based on structure

Based on Occupancy Based on Structure

1. Residential Buildings 1. Load Bearing Structure

2. Educational Buildings 2. Framed Structure

3. Government Buildings 3. Composite Structure

4. Assembly Buildings

5. Commercial Buildings

6. Industrial Buildings

7. Transport Buildings

Residential BuildingsAll those buildings in which sleeping accommodation is provided for dwelling permanently or temporarily with or without cooking or dining facilities are called residential buildings.E.g. Bungalows, flats, cottages, etc.

Bungalow

Villa

Apartment

All those buildings which are meant for imparting training or providing educational facilities right from nursery or primary to higher level are called Educational Buildings.E.g. Schools, Colleges, Libraries, museums, archives, etc.

Educational Buildings

College

School

Library

All those buildings which are meant for the use by government and related ones are known as government buildings.E.g. Parliament, Embassy, Consulate, Post Office, etc.

Government Buildings

Embassy

Parliament

Post Office

All those buildings where group of people assemble or gather for amusement, recreation, social, religious, patriotic or other such purposes.E.g. Assembly halls, theatre, auditorium, churches, temples, etc.

Assembly Buildings

Theatre

Auditorium

Temple

All buildings which are exclusively used for business purpose are known as Commercial Buildings.E.g. Malls, Banks, Shops, Offices, Restaurants, Hotels, Markets, etc.

Commercial Buildings

Bank

Convention Centre

Malls

Any building or part of a building, or structure in which products or materials of all kinds and properties are fabricated, assembled or processed are known as Industrial buildings.E.g. Factories, Workshops, Refineries, Dairies, etc.

Industrial Buildings

Factory

Refinery

Foundary

All those buildings which consists of the means or equipments necessary for the movement of passengers or goods by land, water or airways are called Transport Buildings.E.g. Airports, Railway Stations, Bus Stations, Parking Garages, etc.

Transport Buildings

Airports

Light House

Railway Stations

A structure comprising of slabs, beams and load bearing walls is known as a Load Bearing Structure.Loads from slab/roof are transmitted through walls to the sub-soil below the ground through their foundations.In load bearing structures, thickness of the walls decreases from ground to first and then to second floor to reduce the load on the vertical walls.As a result, compared to upper floors, lower floors will have less carpet area.Such types of structures are suited where hard strata of soil is available at low depth.Individual residential bungalows, tenements, low rise buildings (up to 3 storey), are constructed as load bearing structures.

Load Bearing Structures

It is a structure comprising of slabs resting on beams and beams are supported by a network of columns and whole load of the structure is transferred to the sub-soil below the ground through columns and their footings.Walls don’t bear any load and rest on plinth beams without foundations.This type of structure has more flexibility.R.C.C. is the most suitable material to withstand external loads like compressive, tensile, torsion and shear along with moment.All columns, beams and slabs are connected rigidly and are constructed monolithically.Carpet area is almost same for all floors and is more than load bearing structure.Generally, all multistoried buildings or high rise buildings have framed structure.

Framed Structures

The structures constructed with combination of both load bearing as well as framed structure is called composite structure.The load of slabs is transmitted to the sub-soil below ground by load bearing walls and columns through their foundations.In this type of structure, external walls are treated as load bearing walls and all intermediate supports are in the form of R.C.C. columns.This type of structure is preferred in buildings having large spans such as workshops, halls, warehouses, godowns, etc.3This type of structure have advantages of both load bearing and framed structure.

Composite Structures

Types of Loads Acting On Buildings

Types of Loads Acting on a Building

Dead Load

Live Load

Wind Load

Snow Load

Load due to Rain

Earthquake Load

The dead load includes loads that are relatively constant over time, including the weight of the structure itself, and immovable fixtures such as walls, roof, immovable furniture, etc.Dead load is permanent, immovable and untransferable load of a structure.The dead load of floors, roofs, beams, ceilings, etc. is proportionately transmitted on the surrounding walls.

Dead Load

Weights of common construction materials of a building

Sr. No. Material/Structure Weight (in kg/m3)

1.Brick Masonry Walls : 10 cm thick 20 cm thick

192384

2. Plain Cement Concrete (P.C.C.) 2300

3. Reinforced Cement Concrete (R.C.C.) 2400

4. Bricks 1600 – 1920

5. Steel 7850

6. Cement Plaster, 25 mm thick 52

7. Sand 1760 – 2000

This is the movable, temporary and transferable load on the floor and hence it is variable.The weight of furniture, stored materials, humans, etc. are examples of live loads.It is also known as superimposed load.The live loads are assumed to be acting uniformly over the whole floor area and is distributed proportionately on the wall foundations.

Live Load

Tall buildings are subjected to wind pressure on their exposed faces and inclined or sloppy roof surfaces.The effect of wind pressure is to reduce the pressure on the foundation on the windward side and to increase the pressure on the leeward side.Wind pressure can be measured by the formula :

P = kV2

p = wind pressure in kg/m2

V = velocity of wind in km/hrk = coefficient whose value depends

on various factors such as wind speedTemperature of air, etc.

= 0.0006 (as per building code)

Wind Load

Snow load acts on roofs.Actual load due to snow will depend on the shape of the roof and its capacity to retain the snow.Mountain regions in northern parts of India are subjected to snow fall. Houses in this region experience snow load.The load of snow maybe taken as 2.5 kg/m2 per cm depth of snow.

Snow Load


Load due to Rain

Earthquake causes shaking of ground resulting in shaking/motion of building at its base.Forces acts on the building due to the earthquake especially in horizontal direction.This fore can damage or even collapse the building.Nowadays earthquake resistant buildings are constructed which can resist the severe earthquakes also.

Earthquake Load

Building Components, Their Functions and Dimensions

Sub-Structure• Shallow Foundation

o Spread Footingso Combined Footingso Strap Footingso Mat/Raft Foundations

• Deep Foundation Super Structure

• Plinth• Walls, Columns & Beams• Floors• Sills, Lintels and Weather sheds• Doors, Windows & Ventilators• Roofs & Slabs• Parapet• Stairs, Lifts, Ramps• Building Finishes

Building Components

The basic function of foundation is to transmit the dead – loads, live loads and other loads to the sub – soil on which it rests in such a way that the settlement of the soil does not fail in shear.Foundations are of two types:1. Shallow Foundations2. Deep Foundations

Foundations

If depth of foundation is equal to or less than its width, then it is Shallow Foundation.All shallow foundations should be taken to a minimum depth of 800 mm.If hard strata is at a greater depth, the depth of foundation should be taken to such a depth at which the soil has allowable bearing capacity.The shallow foundations can be classified into the following types:1. Spread footings2. Combined footings3. Strap footings4. Mat or Raft foundation

Shallow Foundation

Spread footings are those which spread the superimposed load of wall or column over a larger area.The spread footings support either a column or a wall.

Spread Footing

A Spread footings which supports two or more columns is termed as combined footing.Combined footing are invariably constructed of reinforced concrete.

Combined Footing

A strap footing consists of two or more footings of individual columns, connected by a beam, called a Strap.

Strap Footing

A raft or mat is a combined footing, which covers the entire area below the whole building or structure and supports all the walls and columns.

Raft Foundation

When the depth of foundation is equal or greater than its width, then it is called Deep 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 of timber, concrete or steel.

Deep Foundation


Plinth


Walls, Columns & Beams


Floors


Sills, Lintels & Weather Sheds


Doors, Windows & Ventilators


Roofs & Slabs


Parapet


Stairs, Lifts & Ramps


Building Finishes

Sr. No. Building Components Functions

1. FoundationIt transmits the load coming from the superstructure on to the sub-soil below it.

2. Plinth

It protects the building from rain water, damp or moisture, insects and transmits the load of superstructure to the foundation.

3. Walls

Provided to enclose or to divide the floor space into rooms as per requirement and also provide privacy, security and protection against sun, rain, etc.

4. ColumnTransmits the load coming from the beams on the sub – soil below it.

5. Sill Supports window frame at bottom.


6. DoorProvides access into the room, offers privacy of sight and sound.

7. Window Opening made in wall for providing light and ventilation.

8. VentilatorSmall opening made in wall, provided at lintel level for removal of exhaust air or foul smell.

9. Roof/SlabIt is the uppermost part of a building to cover the space below and protect it from sun, wind, rain and snow.

10. BeamMedia by which all loads of slab are transferred to vertical supports of a building.


11. LintelSupports the weight of the wall above the openings of doors, windows and ventilator.

12. StairMeans of vertical transportation between the floors. Provides access between various floors.

13. FloorProvides plane surface and supports the occupants, furniture, fixtures and equipments of a building.

14. Watershed/ChajjasGenerally combined with lintels to protect doors, windows or ventilators from sun, rain, wind, etc

15. Parapet Acts as a protective solid balustrade for the users.


1. Foundation

Shallow foundations: Depth≥2T+30Width=2T+30; T=wall thicknessDeep foundations: Depth-10 to30mWidth as per design

2. Plinth Height above ground : 30, 45, 60, 75 or 90

3. WallsLoad bearing walls : 20, 30, 40 cmPartition wall : 10 cm

4. Column

Square : 20 x 20cm, 30 x 30 cmRectangular : 20 x 30cmCircular : 20 Ø, 30 ØFooting: 1x1x1 m pit as per design

5. Sill Sill height : 70, 80 or 90 cm above floor


6. DoorWidth : 0.80(min.), 0.90, 1.0, 1.20 mHeight : 1.80 (min), 2.0, 2.10 m

7. WindowWidth : 0.60, 0.70, 0.90, 1.00, 1.20 mHeight : 1.20 m

8. VentilatorWidth : 0.60, 0.70, 0.90, 1.00, 1.20 mHeight : 0.20 or 0.30 m

9. Roof/Slab R.C.C. slab thickness : 10, 12, 15 or 18 cm

10. BeamDepth:30, 45 or 60 cmWidth : wall thickness or 30, 45, 60 cm


11. LintelLength=width of door/window opening + min. 10 cm bearing on both endsWidth = thickness of wall

12. StairTread : 25 cm, 30 cmRiser : 115 to 20 cmWidth of stair := minimum 1.0 m

13. Floor Ground floor = plinth heightUpper floor = slab thickness

14. Watershed/ChajjasTapered in shape: Front : 7 to 10 cmAt lintel side = height of lintel = 10 to 15 cm

15. ParapetHeight : 1.0m(min.), 1.10, 1.20 or 1.30 m (approx.)Width : 10, 20 or 30 cm