Friday, 25 March 2016

About Stairs


     well Stairs give access from floor to floor. The space/room housing stairs is called staircase. Stairs consists of a number of steps arranged in a single flight or more number of flights.
The requirement of good stairs are
(a) Width: 0.9 m in residential buildings and 1.5 m to 2.5 m in public buildings.
(b) Number of Steps in a Flight: Maximum number of steps in a flight should be limited to 12 to 14,         while minimum is 3.
(c) Rise: Rise provided should be uniform. It is normally 150 mm to 175 mm in residential buildings         while it is kept between 120 mm to 150 mm in public buildings. However in commercial                     buildings more rise is provided from the consideration of economic floor area.
(d) Tread: Horizontal projection of a step in a stair case is called tread. It is also known as going.
     In residential buildings tread provided is 250 mm while in public buildings it is 270 mm - 300mm.
       The following empirical formula is used to decide rise and tread:
       2R + T > 550 mm but < 700 to 600 mm
       where R is rise in mm and T is tread in mm.
(e) Head Room: Head room available in the stair case should not be less than 2.1 m.
(f) Hand Rails: Hand rails should be provided at a convenient height of a normal person which is              from 850 mm to 900 mm.

Types of Stairs

The stairs may be built with wood, concrete masonry or with cast iron. Wooden stairs are not safe,
because of the danger of fire. However they are used in unimportant buildings to access to small areas in the upper floors. Cast iron or steel stairs in the spiral forms were used commonly to reduce stair case area. In many residential buildings masonry stairs are also used. Reinforced concrete stairs are very commonly used in all types of buildings.

Based on the shapes stairs may be classified as:
(a) Straight stairs
(b) Dog legged stairs
(c) Well or open-newel stairs
(d) Geometrical stairs
(e) Spiral stairs
(f) Turning stairs.

(a) Straight Stairs:

 If the space available for stair case is narrow and long, straight stairs may be provided. Such stairs are commonly used to give access to porch or as emergency exits to cinema halls. In this type all steps are in one direction. They may be provided in single flight or in two flights with landing between the two flights.

(b) Dog Legged Stairs: 

It consists of two straight flights with 180° turn between the two. They are very commonly used to give access from floor to floor. Figure 8.36 shows the arrangement of steps in such stairs.
(c) Well or Open-newel Stairs: It differs from dog legged stairs such that in this case there is 0.15 m       to 1.0 m gap between the two adjacent flights. below Figure  shows a typical open-newel stair.

(d) Geometrical Stair: This type of stair is similar to the open newel stair except that well
formed between the two adjacent flights is curved. The hand rail provided is continuous.

(e) Spiral Stairs: These stairs are commonly used as emergency exits. It consists of a central post supporting a series of steps arranged in the form of a spiral. At the end of steps continuous hand rail is provided. Such stairs are provided where space available for stairs is very much limited.below Figure  shows a typical spiral stair. Cast iron, steel or R.C.C. is used for building these stairs.

( f ) Turning Stairs: Apart from dog legged and open newel type turns, stairs may turn in various forms. They depend upon the available space for stairs. Quarter turned, half turned with few steps in between and bifurcated stairs are some of such turned stairs.below Figure shows a bifurcated stair.

Wednesday, 16 March 2016

About Bricks


 As we know bricks are rarely used building material now a days,Brick is obtained by moulding good clay into a block, which is dried and then burnt. This is the oldest building block to replace stone. Manufacture of brick started with hand moulding, sun drying and burning in clamps. A considerable amount of technological development has taken place with better knowledge about to properties of raw materials, better machinaries and improved techniques of moulding drying and burning.
The size of the bricks are of 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm. With
mortar joints, the size of these bricks are taken as 200 mm × 100 mm × 100 mm and 200 mm × 100 mm × 50 mm. However the old size of 8 (3''/ 4 )× 4(1′′/2)×2(5''/8) ″ giving a masonary size of 9″ × 4(1′′/2)× 3″ is still commonly used in India.

Types of Bricks

Bricks may be broadly classified as:
(i) Building bricks
(ii) Paving bricks
(iii) Fire bricks
(iv) Special bricks.

(i) Building Bricks: These bricks are used for the construction of walls.
(ii) Paving Bricks: These are vitrified bricks and are used as pavers.
(iii) Fire Bricks: These bricks are specially made to withstand furnace temperature. Silica bricks
belong to this category.
(iv) Special Bricks: These bricks are different from the commonly used building bricks with
respect to their shape and the purpose for which they are made. Some of such bricks are listed below:
(a) Specially shaped bricks
(b) Facing bricks
(c) Perforated building bricks
(d) Burnt clay hollow bricks
(e) Sewer bricks
( f ) Acid resistant bricks.

(a) Specially Shaped Bricks: Bricks of special shapes are manufactured to meet the
requirements of different situations. Some of them are shown below fig

(b) Facing Bricks: These bricks are used in the outer face of masonry. Once these bricks are provided, plastering is not required. The standard size of these bricks are 190 × 90 × 90 mm or 190 × 90 × 40 mm.
(c) Perforated Building Bricks: These bricks are manufactured with area of perforation of 30 to 45 per cent. The area of each perforation should not exceed 500 mm2. The perforation should be uniformly distributed over the surface. They are manufactured in the size 190 × 190 × 90 mm and 290 × 90 × 90 mm.
(d) Burn’t Clay Hollow Bricks: Figure 1.4 shows a burnt clay hollow brick. They are light
in weight. They are used for the construction of partition walls. They provide good thermal
insulation to buildings. They are manufactured in the sizes 190 × 190 × 90 mm, 290 × 90 × 90 mm and 290 × 140 × 90 mm. The thickness of any shell should not be less than 11 mm and that of any web not less than 8 mm.
(e) Sewer Bricks: These bricks are used for the construction of sewage lines. They are
manufactured from surface clay, fire clay shale or with the combination of these. They
are manufactured in the sizes 190 × 90 × 90 mm and 190 × 90 × 40 mm. The average
strength of these bricks should be a minimum of 17.5 N/mm2 . The water absorption
should not be more than 10 per cent.
( f ) Acid Resistant Bricks: These bricks are used for floorings likely to be subjected to acid
attacks, lining of chambers in chemical plants, lining of sewers carrying industrial wastes
etc. These bricks are made of clay or shale of suitable composition with low lime and
iron content, flint or sand and vitrified at high temperature in a ceramic kiln.

 Properties of Bricks

The following are the required properties of good bricks:
(i) Colour: Colour should be uniform and bright.
(ii) Shape: Bricks should have plane faces. They should have sharp and true right angled corners.
(iii) Size: Bricks should be of standard sizes as prescribed by codes
(iv) Texture: They should possess fine, dense and uniform texture. They should not possess fissures, cavities, loose grit and unburnt lime.
(v) Soundness: When struck with hammer or with another brick, it should produce metallic sound.
(vi) Hardness: Finger scratching should not produce any impression on the brick.
(vii) Strength: Crushing strength of brick should not be less than 3.5 N/mm2. A field test for strength is that when dropped from a height of 0.9 m to 1.0 mm on a hard ground, the brick should not
break into pieces.
(viii) Water Absorption: After immercing the brick in water for 24 hours, water absorption should
not be more than 20 per cent by weight. For class-I works this limit is 15 per cent.
(ix) Efflorescence: Bricks should not show white patches when soaked in water for 24 hours and
then allowed to dry in shade. White patches are due to the presence of sulphate of calcium, magnesium
and potassium. They keep the masonry permanently in damp and wet conditions.
(x) Thermal Conductivity: Bricks should have low thermal conductivity, so that buildings built with them are cool in summer and warm in winter.
(xi) Sound Insulation: Heavier bricks are poor insulators of sound while light weight and hollow
bricks provide good sound insulation.
(xii) Fire Resistance: Fire resistance of bricks is usually good. In fact bricks are used to encase
steel columns to protect them from fire.

Tests on Bricks

The following laboratory tests may be conducted on the bricks to find their suitability:
(i) Crushing strength
(ii) Absorption
(iii) Shape and size and
(iv) Efflorescence.
(i) Crushing Strength: The brick specimen are immersed in water for 24 hours. The frog of the
brick is filled flush with 1:3 cement mortar and the specimen is stored in damp jute bag for 24 hours and then immersed in clean water for 24 hours. The specimen is placed in compression testing machine with 6 mm plywood on top and bottom of it to get uniform load on the specimen. Then load is applied axially at a uniform rate of 14 N/mm2 . The crushing load is noted. Then the crushing strength is the ratio of crushing load to the area of brick loaded. Average of five specimen is taken as the crushing strength.
(ii) Absorption Test: Brick specimen are weighed dry. Then they are immersed in water for a
period of 24 hours. The specimen are taken out and wiped with cloth. The weight of each specimen in
wet condition is determined. The difference in weight indicate the water absorbed. Then the percentage absorption is the ratio of water absorbed to dry weight multiplied by 100. The average of five specimen is taken. This value should not exceed 20 per cent.
(iii) Shape and Size: Bricks should be of standard size and edges should be truely rectangular
with sharp edges. To check it, 20 bricks are selected at random and they are stacked along the length,
along the width and then along the height. For the standard bricks of size 190 mm × 90 mm × 90 mm.
IS code permits the following limits:
Lengthwise: 3680 to 3920 mm
Widthwise: 1740 to 1860 mm
Heightwise: 1740 to 1860 mm.
The following field tests help in acertaining the good quality bricks:
(i) uniformity in size
(ii) uniformity in colour
(iii) structure
(iv) hardness test
(v) sound test
(vi) strength test.
(i) Uniformity in Size: A good brick should have rectangular plane surface and uniform in size.
This check is made in the field by observation.
(ii) Uniformity in Colour: A good brick will be having uniform colour throughout. This
observation may be made before purchasing the brick.
(iii) Structure: A few bricks may be broken in the field and their cross-section observed. The
section should be homogeneous, compact and free from defects such as holes and lumps.
(iv) Sound Test: If two bricks are struck with each other they should produce clear ringing sound.
The sound should not be dull.
(v) Hardness Test: For this a simple field test is scratch the brick with nail. If no impression is
marked on the surface, the brick is sufficiently hard
(vi) Efflorescense: The presence of alkalies in brick is not desirable because they form patches
of gray powder by absorbing moisture. Hence to determine the presence of alkalies this test is performed as explained below:

Place the brick specimen in a glass dish containing water to a depth of 25 mm in a well ventilated
room. After all the water is absorbed or evaporated again add water for a depth of 25 mm. After second evaporation observe the bricks for white/grey patches. The observation is reported as ‘nil’, ‘slight’, ‘moderate’, ‘heavy’ or serious to mean
(a) Nil: No patches
(b) Slight: 10% of area covered with deposits
(c) Moderate: 10 to 50% area covered with deposit but unaccompanied by flaking of the surface.
(d) Heavy: More than 50 per cent area covered with deposits but unaccompanied by flaking of
the surface.
(e) Serious: Heavy deposits of salt accompanied by flaking of the surface.

Classification of Bricks Based on their Quality

The bricks used in construction are classified as:
(i) First class bricks
(ii) Second class bricks
(iii) Third class bricks and
(iv) Fourth class bricks
(i) First Class Bricks: These bricks are of standard shape and size. They are burnt in kilns.
They fulfill all desirable properties of bricks.
(ii) Second Class Bricks: These bricks are ground moulded and burnt in kilns. The edges may
not be sharp and uniform. The surface may be some what rough. Such bricks are commonly used for the
construction of walls which are going to be plastered.
(iii) Third Class Bricks: These bricks are ground moulded and burnt in clamps. Their edges are
somewhat distorted. They produce dull sound when struck together. They are used for temporary and
unimportant structures.
(iv) Fourth Class Bricks: These are the over burnt bricks. They are dark in colour. The shape is
irregular. They are used as aggregates for concrete in foundations, floors and roads.

 Uses of Bricks

Bricks are used in the following civil works:
(i) As building blocks.
(ii) For lining of ovens, furnaces and chimneys.
(iii) For protecting steel columns from fire.
(iv) As aggregates in providing water proofing to R.C.C. roofs.
(v) For pavers for footpaths and cycle tracks.
(vi) For lining sewer lines.

Monday, 14 March 2016

Determination of Liquid Limit of Soil


      This is best method for determination of liquid limit in the laboratory with the aid of the standard mechanical liquid limit device, designed by Arthur Casagrande and adopted by the ISI, as given in IS:2720 (Part V)–1985. The apparatus required are the mechanical liquid limit device, grooving tool, porcelain evaporating dish, flat glass plate, spatula, palette knives, balance, oven wash bottle with
distilled water and containers. The soil sample should pass 425–μ IS Sieve. A sample of about
1.20 N should be taken. Two types of grooving tools—Type A (Casagrande type) and Type B
(ASTM type)—are used depending upon the nature of the soil. 
The cam raises the brass cup to a specified height of 1 cm from where the cup drops upon the block exerting a blow on the latter. The cranking is to be performed at a specified rate of two rotations per second. The grooving tool is meant to cut a standard groove in the soil sample just prior to giving blows.
Air-dried soil sample of 1.20 N passing 425–μ I.S. Sieve is taken and is mixed with water and kneaded for achieving uniformity. The mixing time is specified as 5 to 10 min. by some authorities. The soil paste is placed in the liquid limit cup, and levelled off with the help of the spatula. A clean and sharp groove is cut in the middle by means of a grooving tool. The crank is rotated at about 2 revolutions per second and the number of blows required to make the halves of the soil pat separated by the groove meet for a length of about 12 mm is counted. The soil cake before and after the test are shown in below figThe water content is determined from a small quantity of the soil paste.
This operation is repeated a few more times at different consistencies or moisture contents. The soil samples should be prepared at such consistencies that the number of blows or shocks required to close the groove will be less and more than 25. The relationship between the number of blows and corresponding moisture contents thus obtained are plotted on semi-logarithmic graph paper, with the logarithm of the number of blows on the x-axis, and the moisture contents on the y-axis. The graph thus obtained, i.e., the best fit straight line, is referred to as the "Flow-graph’ or ‘Flow curve’.
                                               Casagrande  apparatus 

The moisture content corresponding to 25 blows from the flow curve is taken as the liquid limit of the soil. This is the practical definition of this limit with specific reference to the liquid limit apparatus and the standard procedure recommended. Experience indicates that such as curve is actually a straight line.
The equation to this straight line will be
               (w2 – w1) = If log10(N1/N2)

where w1 and w2 are the water contents corresponding to the number of blows N1 and N2 and
If is the slope of the flow curve, called the ‘flow index’.

If = (w2 – w1)/log10 (N1/N2)
If the flow curve is extended such that N1 and N2 correspond to one log-cycle difference,
If will be merely the difference of the corresponding water contents.

One-point Method

Attempts have been made to simplify the trial and error procedure of the determination of liquid limit described above. One such is the ‘One-point method’ which aims at determining the liquid limit with just one reading of the number of the blows and the corresponding moisture content. The trial moisture content should be as near the liquid limit as possible. This can be done with a bit of experience with the concerned soils. For soils with liquid limit between 50 and 120%, the accepted range shall require 20 to 30 drops to close the groove. For soils with liquid limit less than 50%, a range of 15 to 35 drops is acceptable. At least two consistent consecutive closures shall be observed before taking the moisture content sample for calculation of the liquid limit. The test shall always proceed from the drier to the water condition of the soil. (IS: 2720, Part V-1970).
The water content wN of the soil of the accepted trial shall be calculated. The liquid limit
wL of the soil shall be calculated by the following relationship.
wL = wN(N/25)x .
N = number of drops required to close the groove at the moisture content wN. Preliminary
work indicates that x = 0.092 for soils with liquid limit less than 50% and x = 0.120 for
soils with liquid limit more than 50%.

Monday, 7 March 2016

The Different Metals Used In Construction As Building Materials

Metals Used In Construction as Building Materials

      As we know their are different metals available and are used in construction for reinforcement and many useful purposes , and these metals broadly classified as ferrous metals and non-ferrous metals. The properties and uses of ferrous metals and some of important non-ferrous materials like aluminium and copper are explained in this chapter.


A ferrous material is the one in which iron is a main constituent. Iron ore is first converted into pig iron and then pig iron is subjected to various metallurgical processes to mix different percentage of carbon and to get the following three useful ferrous materials:
1. Cast iron—carbon content 1.7% to 4.5%
2. Wrought iron—carbon content 0.05% to 0.15%
3. Steel—carbon content 0.25% to 0.25%.
All ferrous materials contain about 0.5 to 3% silica, less than 2% manganese, 0.15% sulphur and
0.6% phosphorous.

1. Cast Iron: Important properties of cast iron are:

(a) Compression strength is 700 N/mm2 and tensile strength is 150 N/mm2.
(b) It is brittle and does not absorb shocks
(c) Its specific gravity is 7.5.
(d) Its structure is coarse, crystalline and fibrous.
(e) It cannot be magnetised.
(f) It does not rust-easily.
(g) It has low melting point of about 1200°C.

Uses of Cast Iron:
(a) 1. It is used for making rain water and sanitary pipes, sanitary fittings and manhole covers.
      2. It is used for making railings and spiral stair cases.
      3. Fire gratings, cover for pumps and motors and brackets are made with cast irons.

2. Wrought Iron: 

It is almost pure iron. It contains less than 0.15% carbon. Attempts are made
to reduce the other impurities during the process of manufacturing.
Properties of Wrought Iron:
1. Its ultimate compressive strength is 200 N/mm2 and ultimate tensile strength is 375 N/mm2.
2. It is ductile and brittle.
3. Its unit weight is 77 kN/m3.
4. It melts at about 1500°C. It becomes so soft at 900°C that two pieces can be joined by hammering.
5. It can absorb shocks very well.
6. It forms temporary magnets but it cannot be magnetised permanently.
7. It rusts more easily.

Uses of Wrought Iron:
1. It is used for making nails nuts and botts, wires and chains.
2. It is used for making roofing sheets, grills, fences, window gaurds etc.

3. Steel: 

It is extensively used building material. The following three varieties of steel are extensively used:
(a) Mild steel
(b) High carbon steel and
(c) High tensile steel.

 It contains a maximum of 0.25% carbon, 0.055% of sulphur and 0.55% of phosphorus.
Properties of Mild Steel:
(i) It is malleable and ductile
(ii) It is more elastic
(iii) It can be magnetized permanently.
(iv) Its specific gravity is 7.8.
(v) Its Young’s modulus is 2.1 × 105 N/mm2.
(vi) It can be welded easily.
(vii) It is equally strong in tension and in compression.

Uses of Mild Steel:
(i) Round bars are extensively used as reinforcement in R.C.C. works.
(ii) Rolled sections like I, T, L, C, plates etc. are used to build steel columns, beams, trusses etc.
(iii) Tubular sections are used as poles and members of trusses.
(iv) Plain and corrugated mild steel are used as roofing materials.
(v) Mild steel sections are used in making parts of many machineries.

The carbon containts in this steel is 0.7% to 1.5%. Properties of Carbon Steel:
(i) It is more tough and elastic compared to mild steel.
(ii) Welding is difficult.
(iii) It can be magnetized permanently.
(iv) It is stronger in compression than in tension.
(v) It withstands shocks and vibrations better.

Uses of High Carbon Steel:
(i) It is used for making tools such as drills, files, chisels.
(ii) Many machine parts are made with high carbon steel since it is capable of withstanding
shocks and vibrations.

 It contains 0.8% carbon and 0.6% manganese. The strength of this steel
is quite high. High tensile steel wires are used in prestressed concrete works.


It is present on the surface of earth crust in most of the rooks and clay. But to produce the metal bauxite (Al2O3. 2H2O) is ideally suited ore.
Properties of Aluminium
1. It is having silver colour and bright lustre.
2. It is very light in weight.
3. It is good conductor of electricity.
4. It has very good resistance to corrosion.
5. It melts at 66°C.
6. It is highly ductile and malleable.
7. It has high strength to weight ratio.

Uses of Aluminium
1. It is used to make door and window frames.
2. Aluminium structural members are becoming popular.
3. Aluminium wires are used as conductors of electricity.
4. It is used as a foil.
5. Aluminium powder serves as pigments in paints.


It is a naturally available metal in the form of ores which contain small amount of iron and sulphur.
After removing impurities, it is processed electrolytically to get purest metal. This metal is almost
indestructible. Copper scrap can be processed to get original copper.

Properties of Copper
1. It is having reddish brown colour.
2. Its structure is crystalline.
3. It is highly ductile and malleable.
4. It resists corrossion.
5. It can be welded easily at red heat condition.
6. Dents on the copper can be hammered out.
7. It has high electric and thermal conductivity.
8. Its melting point is at 1083°C.

Uses of Copper:-
1. It is used as electric wire and cable.
2. It is used as lighting conductor.
3. For water proofing the construction joints copper plates are used.
4. Copper tubes are used for hot and cold water supply, gas and sanitation connections.
5. It forms a major constituent of brass and bronze.

Subject-Wise Civil Engineering eBooks


Structutal Analysis - IIT Kharagpur Course Material

Structural Analysis in Theory and Practice by Alan Williams 

Structural Analysis by Aslam Kassimali - 4th edition


Elements of the Theory of Structures by JACQUES HEYMAN

Advanced Methods of Structural Analysis by Igor A. Karnovsky and Olga Lebed

Structural Steel Drafting and Design MacLaughlin


Structural Engineer's Pocket_Book


Structural Design Guide to the ACI_Building_Code__4th ed 1998




Reinforced Cement Concrete 

Design of Reinforced Concrete by Mashhour Ghoneim and Mahmoud El-Mihilmy

Reinforced Concrete Designers Handbook by Charles E.Reynolds and James C.Steedman

Reinforced Concrete Design of Tall Buildings by Bungale S Taranath


Reinforced Concrete Design Theory and Examples by T.J.MACGINLEY and B.S.CHOO

Limit State Design of Reinforced Concrete by P.C. Varghese - Prentice Hall of India

Design of Reinforced Concrete by Jack C. McCormac and Russell H.Brown 9th Edition

Pre-stressed Concrete


surveying by chandra

Fundamentals of Surveying by SK_Roy

Engineering surveying by w.schofield and m.breach

Finite element Analysis

Advanced Geotechnical Analyses by P.K.Benerjee and R.Butterfield

Theoretical Soil Mechanics by Karl Terzaghi


Principles of Foundation Engineering - 7th Edition by Braja M Das

Pile Foundations in Engineering Practice by S.Prakash and Hari D Sharma

Numerical Methods in Geotechnical Engineering by Chandrakanth S Desai and John T Christian

Geotechnical Engineering - Principles and Practices of Soil Mechanics and Foundation Engineering by VNS Murthy

Foundation Engineering Handbook based on IBC 2006 Robert W Day

An Introduction to Soil Mechanics and Foundations by C.R. Scott

Concrete Technology 

Formwork for Concrete Structures by R.L.Peurifoy and G.D.Oberlender


Concrete Mix Design, Quality Control and Specification by Ken W. Day

CONCRETE ADMIXTURES HANDBOOK Properties, Science, and Technology by 

Advanced Concrete Technology Testing and Quality by John Newman and Ban Seng Choo

Building Engineering Science 

Building Construction and Materials Notes

Fundamentals of Building Construction materials and methods by Edward Allen and Joseph Iano


BUILDING DESIGN AND CONSTRUCTION HANDBOOK by Frederick S. Merritt and Jonathan T. Ricketts

Transportation Engineering

Transport Planning and Traffic Engineering by C A O'Flaherty


Pavement Analysis and Design by Yang H Huang

Highway and Traffic Engineering in Developing Countries

Airport Engineering Planning, Design, and Development of 21st Century Airports

Fluid Mechanics and Hydraulics

Fluid Mechanics by Pijush K. Kundu, Ira M. Cohen

Fluid Mechanics by Joseph Spurk, Nuri Aksel 2nd Edition

Fluid Mechanics with Engineering Applications - Robert L Daugherty, Joseph B Franzini

Engineering Geology 

Engineering Geology by F.G. Bell


Foundations of Engineering Geology by Tony Waltham

Engineering Geology - Principles and Practice by David George Price

Encyclopedia of Geology by Richard C Selley, L.Robin M.Cocks, Ian R.Plimer

Environmental Engineering

Water, Wastewater, and Stormwater Infrastructure Management by NEIL S. GRIGG

Water, Sanitary and Waste Services for Buildings by A.F.E Wise and J.A. Swaffield

Water Supply by Alan C Twort, Don D Ratnayaka and Malcolm J Brandt

Sanitation and Water Supply Handbook by Tony Gage

Environmental Engineering Dictionary and Directory by Thomas M.Pankratz

Environmental Engineering by Anil Kumar De and Arnab Kumar De

ENVIRONMENTAL ENGINEERING - Water, Wastewater, Soil and Groundwater Treatment and Remediation

Engineering Sewerage by Ronald E.Bartlett

Basic Environmental Engineering by R.C.Gaur

Irrigation Engineering

Hydraulics of Dams and River Structures by Dr. Farhad Yazdandoost and Dr. Jalal Attari

Water Resources Systems Planning and Management by S.K.Jain and V.P.Singh



Irriagtion Engineering and Hydraulic Structures by Santosh Kumar Garg

HYDROLOGY A Science of Nature by Andre Musy and Christophe Higy

Saturday, 5 March 2016

About Soil -(Formation,soil profile,structure of soil,types)

Soil Formation

Soil is formed by the process of ‘Weathering’ of rocks, that is, disintegration and decomposition
of rocks and minerals at or near the earth’s surface through the actions of natural or mechanical
and chemical agents into smaller and smaller grains. The factors of weathering may be atmospheric, such as changes in temperature and pressure; erosion and transportation by wind, water and glaciers; chemical action such as crystal growth, oxidation, hydration, carbonation and leaching by water, especially rainwater, with time.
             Obviously, soils formed by mechanical weathering (that is, disintegration of rocks by the action of wind, water and glaciers) bear a similarity in certain properties to the minerals in the parent rock, since chemical changes which could destroy their identity do not take place. It is to be noted that 95% of the earth’s crust consists of igneous rocks, and only the remaining 5% consists of sedimentary and metamorphic rocks. However, sedimentary rocks are present on 80% of the earth’s surface area. Feldspars are the minerals abundantly present (60%) in igneous rocks. Amphiboles and pyroxenes, quartz and micas come next in that order. Rocks are altered more by the process of chemical weathering than by mechanical weathering. In chemical weathering some minerals disappear partially or fully, and new compounds are formed. The intensity of weathering depends upon the presence of water and temperature and the dissolved materials in water. Carbonic acid and oxygen are the most effective dissolved materials found in water which cause the weathering of rocks. Chemical weathering has the maximum intensity in humid and tropical climates.
‘Leaching’ is the process whereby water-soluble parts in the soil such as Calcium Carbonate, are dissolved and washed out from the soil by rainfall or percolating subsurface water.
‘Laterite’ soil, in which certain areas of Kerala abound, is formed by leaching. Harder minerals will be more resistant to weathering action, for example, Quartz present in igneous rocks. But, prolonged chemical action may affect even such relatively stable minerals, resulting in the formation of secondary products of weatheing, such as clay minerals— illite, kaolinite and montmorillonite. ‘Clay Mineralogy’ has grown into a very complicated and broad subject.

Soil Profile 

         A deposit of soil material, resulting from one or more of the geological processes described
earlier, is subjected to further physical and chemical changes which are brought about by the climate and other factors prevalent subsequently. Vegetation starts to develop and rainfall begins the processes of leaching and eluviation of the surface of the soil material. Gradually, with the passage of geological time profound changes take place in the character of the soil. These changes bring about the development of ‘soil profile’. Thus, the soil profile is a natural succession of zones or strata below the ground surface and represents the alterations in the original soil material which have been brought about by weathering processes. It may extend to different depths at different places and each stratum
may have varying thickness.
Generally, three distinct strata or horizons occur in a natural soil-profile; this number
may increase to five or more in soils which are very old or in which the weathering processes
have been unusually intense. From top to bottom these horizons are designated as the A-horizon, the B-horizon and the C-horizon. The A-horizon is rich in humus and organic plant residue. This is usually eluviated and leached; that is, the ultrafine colloidal material and the soluble mineral salts
are washed out of this horizon by percolating water. It is dark in colour and its thickness may
range from a few centimetres to half a metre. This horizon often exhibits many undesirable
engineering characteristics and is of value only to agricultural soil scientists.

The B-horizon is sometimes referred to as the zone of accumulation. The material which
has migrated from the A-horizon by leaching and eluviation gets deposited in this zone. There
is a distinct difference of colour between this zone and the dark top soil of the A-horizon. This
soil is very much chemically active at the surface and contains unstable fine-grained material.
Thus, this is important in highway and airfield construction work and light structures such as
single storey residential buildings, in which the foundations are located near the ground
surface. The thickness of B-horizon may range from 0.50 to 0.75 m.
The material in the C-horizon is in the same physical and chemical state as it was first
deposited by water, wind or ice in the geological cycle. The thickness of this horizon may range
from a few centimetres to more than 30 m. The upper region of this horizon is often oxidised to
a considerable extent. It is from this horizon that the bulk of the material is often borrowed for
the construction of large soil structures such as earth dams.
Each of these horizons may consist of sub-horizons with distinctive physical and chemical
characteristics and may be designated as A1, A2, B1, B2, etc. The transition between horizons
and sub-horizons may not be sharp but gradual. At a certain place, one or more horizons
may be missing in the soil profile for special reasons. A typical soil profile is shown below
The morphology or form of a soil is expressed by a complete description of the texture,
structure, colour and other characteristics of the various horizons, and by their thicknesses
and depths in the soil profile. 


Soils which are formed by weathering of rocks may remain in position at the place of region. In
that case these are ‘Residual Soils’. These may get transported from the place of origin by various agencies such as wind, water, ice, gravity, etc. In this case these are termed ‘‘Transported soil’’. Residual soils differ very much from transported soils in their characteristics and engineering behaviour. The degree of disintegration may vary greatly throughout a residual soil mass and hence, only a gradual transition into rock is to be expected. An important characteristic of these soils is that the sizes of grains are not definite because of the partially disintegrated condition. The grains may break into smaller grains with the application of a little pressure.
    The residual soil profile may be divided into three zones: (i) the upper zone in which there is a high degree of weathering and removal of material; (ii) the intermediate zone in which there is some degree of weathering in the top portion and some deposition in the bottom portion; and (iii) the partially weathered zone where there is the transition from the weathered material to the unweathered parent rock. Residual soils tend to be more abundant in humid and warm zones where conditions are favourable to chemical weathering of rocks and have sufficient vegetation to keep the products of weathering from being easily transported as sediments. Residual soils have not received much attention from geotechnical engineers because these are located primarily in undeveloped areas. In some zones in South India, sedimentary soil deposits range from 8 to 15 m in thickness.
Transported soils may also be referred to as ‘Sedimentary’ soils since the sediments, formed by weathering of rocks, will be transported by agencies such as wind and water to places far away from the place of origin and get deposited when favourable conditions like a decrease of velocity occur. A high degree of alteration of particle shape, size, and texture as also sorting of the grains occurs during transportation and deposition. A large range of grain sizes and a high degree of smoothness and fineness of individual grains are the typical characteristics of such soils.
Transported soils may be further subdivided, depending upon the transporting agency
and the place of deposition, as under:
Alluvial soils- Soils transported by rivers and streams: Sedimentary clays.
Aeoline soils- Soils transported by wind: loess.
Glacial soils- Soils transported by glaciers: Glacial till.
Lacustrine soils- Soils deposited in lake beds: Lacustrine silts and lacustrine clays.
Marine soils. Soils deposited in sea beds: Marine silts and marine clays.
Broad classification of soils may be:
1. Coarse-grained soils, with average grain-size greater than 0.075 mm, e.g., gravels and sands.
2. Fine-grained soils, with average grain-size less than 0.075 mm, e.g., silts and clays.
These exhibit different properties and behaviour but certain general conclusions are possible even with this categorisation. For example, fine-grained soils exhibit the property of
‘cohesion’—bonding caused by inter-molecular attraction while coarse-grained soils do not;
thus, the former may be said to be cohesive and the latter non-cohesive or cohesionless.
Further classification according to grain-size and other properties is given in later chapters.

The following are some commonly used soil designations, their definitions and basic properties:

Bentonite-Decomposed volcanic ash containing a high percentage of clay mineral—
montmorillonite. It exhibits high degree of shrinkage and swelling.

Black cotton soil- Black soil containing a high percentage of montmorillonite and colloidal
material; exhibits high degree of shrinkage and swelling. The name is derived from the
fact that cotton grows well in the black soil.

Boulder clay.-Glacial clay containing all sizes of rock fragments from boulders down to
finely pulverised clay materials. It is also known as ‘Glacial till’.

Caliche- Soil conglomerate of gravel, sand and clay cemented by calcium carbonate.

Hard pan- Densely cemented soil which remains hard when wet. Boulder clays or glacial
tills may also be called hard-pan— very difficult to penetrate or excavate.

Laterite- Deep brown soil of cellular structure, easy to excavate but gets hardened on
exposure to air owing to the formation of hydrated iron oxides.

Loam.-Mixture of sand, silt and clay size particles approximately in equal proportions;
sometimes contains organic matter.

Loess- Uniform wind-blown yellowish brown silt or silty clay; exhibits cohesion in the
dry condition, which is lost on wetting. Near vertical cuts can be made in the dry condition.

Marl-Mixtures of clacareous sands or clays or loam; clay content not more than 75%
and lime content not less than 15%.

Moorum- Gravel mixed with red clay.
Top-soil- Surface material which supports plant life.
Varved clay- Clay and silt of glacial origin, essentially a lacustrine deposit; varve is a term of Swedish origin meaning thin layer. Thicker silt varves of summer alternate with thinner
clay varves of winter.

Structure Of Soils

The ‘structure’ of a soil may be defined as the manner of arrangement and state of aggregation
of soil grains. In a broader sense, consideration of mineralogical composition, electrical properties,
orientation and shape of soil grains, nature and properties of soil water and the interaction
of soil water and soil grains, also may be included in the study of soil structure, which is
typical for transported or sediments soils. Structural composition of sedimented soils influences,
many of their important engineering properties such as permeability, compressibility
and shear strength. Hence, a study of the structure of soils is important.
The following types of structure are commonly studied:
(a) Single-grained structure
(b) Honey-comb structure
(c) Flocculent structure

Single-grained Structure

Single-grained structure is characteristic of coarsegrained soils, with a particle size greater than 0.02
mm. Gravitational forces predominate the surface forces and hence grain to grain contact results. The
deposition may occur in a loose state, with large voids or in a sense state, with less of voids.

Honey-comb Structure

This structure can occur only in fine-grained soils, especially in silt and rock flour. Due to the relatively smaller size of grains, besides gravitational forces, inter-particle surface forces also play an important role in the process of settling down. Miniature arches are formed, which bridge over relatively large void spaces. This results in the formation of a honey-comb structure, each cell of a honey-comb being made up of numerous individual soil grains. The structure has a large void
space and may carry high loads without a significant volume change. The structure can be broken down by external disturbances.

Flocculent Structure

This structure is characteristic of fine-grained soils such as clays. Inter-particle forces play a predominant role in the deposition. Mutual repulsion of the particles may be eliminated by means of an appropriate chemical; this will result in grains coming closer together to form a ‘floc’. Formation of flocs is ‘flocculation’. But the flocs tend to settle in a honeycomb structure, in which in place of each grain, a floc occurs. Thus, grains grouping around void spaces larger than the grain-size are flocs and flocs grouping around void spaces larger than even the flocs result in the formation of a ‘flocculent’ structure. Very fine particles or particles of colloidal size (< 0.001 mm) may be in a flocculated or dispersed state. The flaky particles are oriented edge-to-edge or edge-to-face with respect to one another in the case of a flocculated structure. Flaky particles of
clay minerals tend to from a card house structure (Lambe, 1953), when flocculated. This is shown in below fig, When inter-particle repulsive forces are brought back into play either by remoulding or by
the transportation process, a more parallel arrangement or reorientation of the particles occurs,  This means more face-to-face contacts occur for the flaky particles when these are in a dispersed state. In practice, mixed structures occurs especially in typical marine soils.

Friday, 4 March 2016

Learn How To Plan For proper Building Planning


In this Post Discussed about basic requirements of buildings are presented and then planning of the building with respect to orientation, utility of space, energy efficiency and other requirements are explained.


The following are the basic elements of a building:
1. Foundation
2. Plinth
3. Walls and columns
4. Sills, lintels and chejjas
5. Doors and windows
6. Floors
7. Roofs
8. Steps, stairs and lifts
9. Finishing work
10. Building services.
The functions of these elements and the main requirement of them is presented in this article.
1. Foundation: Foundation is the most important part of the building. Building activity starts
with digging the ground for foundation and then building it. It is the lower most part of the building. It transfers the load of the building to the ground. Its main functions and requirements are:
(a) Distribute the load from the structure to soil evenly and safely.
(b) To anchor the building to the ground so that under lateral loads building will not move.
(c) It prevents the building from overturning due to lateral forces.
(d) It gives level surface for the construction of super structure.

2. Plinth: The portion of the wall between the ground level and the ground floor level is called
plinth. It is usually of stone masonry. If the foundation is on piles, a plinth beam is cast to support wall above floor level. At the top of plinth a damp proof course is provided. It is usually 75 mm thick plain concrete course. The function of the plinth is to keep the ground floor above ground level, free of dampness. Its height is not less than 450 mm. It is required that plinth level is at least 150 mm above the road level, so that connections to underground drainage system can be made.

3. Walls and Columns: The function of walls and columns is to transfer the load of the structure
vertically downwards to transfer it to foundation. Apart from this wall performs the following functions
(a) It encloses building area into different compartments and provides privacy.
(b) It provides safety from burglary and insects.
(c) It keeps the building warm in winter and cool in summer.

4. Sills, Lintels and Chejjas: A window frame should not be directly placed over masonry. It is
placed over 50 mm to 75 mm thick plain concrete course provided over the masonry. This course is
called as sill. Lintels are the R.C.C. or stone beams provided over the door and window openings to
transfer the load transversely so as to see that door or window frame is not stressed unduly. The width
of lintels is equal to the width of wall while thickness to be provided depends upon the opening size.
Chejja is the projection given outside the wall to protect doors and windows from the rain. They are
usually made with R.C.C. In low cost houses stone slabs are provided as chejjas. The projection of
chejja varies from 600 mm to 800 mm. Sometimes drops are also provided to chejjas to improve acsethetic look and also to get additional protection from sun and rain.

5. Doors and Windows: The function of a door is to give access to different rooms in the
building and to deny the access whenever necessary. Number of doors should be minimum possible.
The size of the door should be of such dimension as will facilitate the movement of the largest object
likely to use the door.
Windows are provided to get light and ventilation in the building. They are located at a height of 0.75 m to 0.9 m from the floor level. In hot and humid regions, the window area should be 15 to 20 per cent of the floor area. Another thumb rule used to determine the size and the number of windows is for every 30 m3 of inside volume there should be 1 m2 window opening.

6. Floors: Floors are the important component of a building. They give working/useful area for
the occupants. The ground floor is prepared by filling brick bats, waste stones, gravel and well compacted with not less than 100 mm sand layer on its top. A lean concrete of 1 : 4 : 8, 100 mm thick is laid. On this a damp proof course may be provided. Then floor finishing is done as per the requirement of the owner. Cheapest floor finish for a moderate house is with 20 to 25 mm rich mortar course finished with red oxide. The costliest floor finish is mossaic or marble finishing.
Other floors are usually of R.C.C. finished as per the requirements of the owner.

7. Roof: Roof is the top most portion of the building which provide top cover to the building. It
should be leak proof. Sloping roof like tiled and A.C. sheet give leak proof cover easily. But they do not give provision for the construction of additional floor. Tiled roof give good thermal protection.
Flat roofs give provision for additional floors. Terrace adds to the comfort of occupants. Water
tanks can be easily placed over the flat roofs.

8. Step, Stairs and Lifts: Steps give convenient access from ground level to ground floor level.
They are required at doors in the outer wall. 250 to 300 mm wide and 150 mm rise is ideal size for
steps. In no case the size of two consecutive steps be different. Number of steps required depends upon the difference in the levels of the ground and the floor. Stairs give access from floor to floor. They should consists of steps of uniform sizes.
In all public buildings lifts are to be provided for the conveniences of old and disabled persons.
In hostels G + 3 floors can be built without lifts, but in residential flats maximum floors permitted
without lifts is only G + 2. Lift is to be located near the entrance. Size of the lift is decided by the
number of users in peak hours. Lifts are available with capacity 4 to 20 persons.

9. Finishing: Bottom portion of slab (ceiling), walls and top of floor need smooth finishing
with plaster. Then they are provided with white wash, distemper or paints or tiles. The function of
finishing work is:
(a) Give protective cover
(b) Improve aesthetic view
(c) Rectify defective workmanship
(d) Finishing work for plinth consists in pointing while for floor it consists in polishing.

10. Building Services: Water supply, sanitation and drainage works, electric supply work and
construction of cupboards and show cases constitute major building services.
For storing water from municipal supply or from tanker a sump is built in the house property
near street. From the sump water is pumped to over head tanks placed on or above roof level so as to get water all the 24 hours. Plumbing work is made so as to get water in kitchen, bathrooms, water closets,sinks and garden taps.
For draining rain water from roofs, down take pipes of at least 100 mm diameters should be
used. Proper slopes should be given to roof towards down take pipe. These pipes should be fixed at 10 to 15 mm below the roof surface so that rain water is directed to the down take pipe easily.
The sanitary fittings are to be connected to stone ware pipes with suitable traps and chambers.
Stone ware pipes are then connected to underground drainage of municipal lines or to the septic tank.
Many carpentry works are required for building service. They are in the form of showcases,
cupboards, racks etc.
Electric supply is essential part of building services. The building should be provided with
sufficient points for supply of lights, fans and other electric gadgets.


The planning and construction of a building should be aimed at fulfilling the following requirements:
1. Strength and stability
2. Dimensional stability
3. Resistance to dampness
4. Resistance to fire
5. Heat insulation
6. Sound insulation
7. Protection against termite attack
8. Durability
9. Security against burglary
10. Lighting and ventilation
11. Comforts and convenience
12. Economy.

1. Strength and Stability: Building should be capable of transferring the expected loads in its
life period safely to the ground. Design of various structural components like slabs, beams, walls,
columns and footing should ensure safety. None of the structural components should buckle, overturn
and collapse.

2. Dimensional Stability: Excessive deformation of structural components give a sense of
instability and result into crack in walls, flooring etc. All structural components, should be so designed that deflections do not exceed the permissible values specified in the codes.

3. Resistance to Dampness: Dampness in a building is a great nuisance and it may reduce the
life of the building. Great care should be taken in planning and in the construction of the building to
avoid dampness.

4. Resistance to Fire: Regarding achieving resistance to fire, the basic requirements laid down
in the codes are:
(a) the structure should not ignite easily.
(b) building orientation should be such that spread of fire is slow.
(c) In case of fire, there should be means of easy access to vacate building quickly.

5. Heat Insulation: A building should be so oriented and designed that it insulates interior
from heat.

6. Sound Insulation: Buildings should be planned against outdoor and indoor noises.

7. Protection from Termite: Buildings should be protected from termites.

8. Durability: Each and every component of the building should be durable.

9. Security against Burglary: This is the basic need the owner of the building expects.

10. Lighting and Ventilation: For healthy and happy living natural light and ventilations are
    required. Diffused light and good cross ventilation should be available inside the building.

11. Comforts and Conveniences: Various units in the building should be properly grouped and
integrated keeping in mind the comfort and convenience of the user.

12. Economy: Economy without sacrificing comfort, convenience and durability is another basic
requirement of the building.


All buildings should be properly planned, keeping in view the various requirements of a good building.
Except strength requirement, all other requirements of a good buildings are taken care at the stage of
planning. Strength requirement is taken care during structural design of building components. However
in planning the building by-laws of the statutory authorities should not be violated. Planning of the
building is an art combined with science.
Principles of planning of buildings may be grouped into:
1. Orientation
2. Energy efficiency
3. Utility
4. Other requirements of the building. These principles are briefly explained in the articles 6.4 to 6.7.


Orientation means setting out the plan of the building with respect to north-south and east-west directions to provide an opportunity to user to enjoy sun-shine and breeze when required and to avoid the same whenever not required. This is also known as planning the aspect of a building. Aspect means arrangement of doors, windows in the external wall to make good use of nature. This term has nothing to do with the architectural aspect of outlook of building. Kitchen should have eastern aspect to enjoy morning sunshine, means, kitchen should be located on the eastern side of the building to make use of morning sun rays. The following are the required aspects for various parts of the building in the northern hemisphere of earth:
(a) Kitchen–eastern aspect.
(b) Dining room–southern aspect to enjoy winter sun.
(c) Drawing and living room–southern or south-eastern aspect to enjoy winter sun.
(d) Bed rooms–western or south-western aspect to enjoy breez in summer.
(e) Reading room, class room, stairs, northern aspect to enjoy diffused light.

The following suggestions should be kept in mind in the orientation of a building in India:
(a) Place long walls towards north-south and short walls in east-west directions so as to reduce
the area exposed to direct sun rays.
(b) Provide verandah and balcony on east and west.
(c) Provide chejjas on doors and windows on southern side to protect them from sun’s rays.


A building should be planned in such a manner that it gives maximum day lighting, ventilation and heat insulation. If these requirements are fulfilled, requirement of electric energy comes down.
(a) Light: Natural light provides hygenic atmosphere. Light should not be glaring but it should
be uniformly distributed. Providing windows and ventilators of appropriate size at suitable positions
contributes a lot for natural lighting. For residential buildings window area to floor area should not be
less than 1/10th while for school buildings it should not be less than 1/5th of floor area. For factory
buildings north light trusses should be provided to get maximum diffused light.

(b) Ventilation: Ventilation is the circulation of the air in the building. Natural ventilation can be
achieved by selecting and positioning of doors, windows and ventilators at suitable places. Always
cross ventilations should be planned suitably. Provision of ventilators at roof level helps in driving out hot airs. In case it is not possible to achieve natural ventilation for any part of the building provide ordinary or exhaust fans.

(c) Heat Insulation: Thicker exterior walls provide insulation against heat. Proper ventilation
also helps in achieving heat insulation. Sun shades provided to doors, windows and ventilators help in
achieving heat insulation. In factories and assembly halls height should be more to reduce temperature inside the building. The position of furnaces in the factories should be located away from the other parts of the factory. The openings should be provided at higher level in the wall to remove hot air.


Principles of planning for suitable utility are:
1. Roominess
2. Furniture Requirements
3. Groupings
4. Circulation.

1. Roominess: It refers to suitable proportioning of length, width and height of rooms in the
building to get maximum benefit from the minimum dimensions. Length to width ratio should be 1.2 to 1.5. If it is nearly square lot of area is wasted for movement, while, it is more than 1.5, it gives the
‘tunnel’ effect. Doors for rooms should be properly located so that utility and privacy are maximum.
Cupboards and lofts should be provided to increase roominess. Proper colours to wall and floor also
give roominess effect. Light colour gives effect of more space.

2. Furniture Requirements: In planning residential, office, laboratory, hospital buildings
positions of required furniture should be drawn and then room dimensions, positions of doors, windows,wardsities etc. planned. In case of planning a hostel room for two students it may need centrally placed door while if it is for three students, it should be near the end of front wall. Positions of cots, study tables and cupboard should be drawn and room planned. In designing a living room, positions of sofa, chairs, T.V. show case etc. should be drawn and size of the room and positions of doors fixed. Availability of circulation area should be checked. Thus the furniture requirement influences the planning of a building to a great extent.

3. Grouping: Grouping means disposition of various rooms in the building for the convenience
of users and their utility. A dining room should be close to the kitchen, white sanitary block should be
away from kitchen, but convenient to bedrooms. In case of offices, administrative department is located centrally. In factories, various sections are located such that product moves in one direction to get finally assembled after least movement. In residential buildings grouping is to achieve comfort, privacy and efficiency while in the case of other buildings it is to achieve economical service.

4. Circulation: Circulation means the space to be provided for movement from room to room
or floor to floor. Passages, lobbies, halls provided serve horizontal circulation while stairs and lifts
serve vertical circulation. Within a room also a portion of it serve for circulation while some other
portion serve for utility. The following points should be considered in planning circulation:
(a) They should be straight.
(b) They should be sufficient.
(c) They should be sufficiently lighted and ventilated.
(d) Stairs should be easily accessible to all the users.
(e) Sanitary services should have access for every user through passage lobby.


Principle of planning involves planning for meeting the following requirements also:
1. Sanitary convenience
2. Prospects
3. Elegance
4. Flexibility
5. Privacy
6. Resistance to fire
7. Sound insulation
8. Protection from termite
9. Security against burglary
10. Economy
11. Provisions for future alterations.

1. Sanitary Convenience: Sanitary conveniences include provision of bathrooms, lavatories,
urinals etc. Provision of these are not only necessities but statutory requirement also. These facilities
should be located giving free access to all users. In these blocks, suitable slopes should be given to the floors to drain out water easily.

2. Prospects: It is about locating and selecting types of doors and windows so as to reveal
pleasant features and conceal undesirable features of the buildings from a person viewing from outside.

3. Elegance: Elegance means general effect produced for a viewer from outside. It depends
upon proper positioning of doors, windows, ventilators, chejjas, balconies etc. Elevations should be
attractive. The width, height and the projections in the building contribute a lot for the elegance. Taj
Mahal is an example famous for its elegance.

4. Flexibility: This aspect of planning means a room designed for a specific purpose should be
possible to use for other purposes, if necessary. A study room may be planned for using as a guest room. If partition is provided between living room and dining room, it is possible to remove partition and use living room plus dining room for the family functions. If independent access is given to backyard from kitchen, backyard can be used for dinner functions. Thus in planning flexibility also should be considered.

5. Privacy: Planning should take care of privacy of one room from other room in a building as
well as some parts of a building from neighbouring buildings and from streets. It is ensured by proper
grouping of rooms and by suitably providing doors, windows and ventilators. Planning the entrance at appropriate position also contributes a lot in providing privacy.

6. Resistance to Fire: It may be noted that concrete and masonry (stone or brick) have better
resistance to fire while steel and wood have lesser resistance. Hence reduce use of steel and wood in
kitchen and bathrooms with electric heaters. Kitchen should be so located that if fire is caught it is
directed away from the building by the wind rather than towards the building. In public buildings and
assembly halls stair cases should be easily accessible and always more than one is provided.

7. Sound Insulation: Noise pollution can be reduced by suitable planning of the building.
Some of them are:
(a) Orienting the building suitably so that rooms are kept away from road side.
(b) Using hollow blocks for the walls.
(c) Plugging door and window openings tightly.
(d) Using false ceilings.
(e) By fixing water closet cisterns on outer walls instead on wall common to rooms.
(f) By fixing water closet pan on a thin pad.
(g) Holding pipes passing through walls and floors by insulated clips.

8. Protection from Termite: Building should be protected from termite attack by
(a) Treating the foundation with chemicals at the time of construction.
(b) Using well seasoned and well treated wood in the building.

9. Security against Burglary: By providing thicker walls, using stronger doors and windows
in outer walls, security against burgling is improved. Providing grills to windows and additional doors are some of the methods of improving security. Alarms fitted in walls, roofs also improve security of the buildings.

10. Economy: Economy without sacrificing comfort, conveniences and durability is another
basic principle of planning a building. For this circulation area should be minimised. Materials should
be so selected that maintenance cost is minimized.

11. Provision for Future Expansion: Building should be planned making suitable provision for
future expansion. Some of the steps required for it are:
(a) Improving elevations without dismantling any part during future expansion.
(b) Extending building horizontally or vertically without damaging the existing building.
(c) Improving the flooring.

Wednesday, 2 March 2016

Use Of Sea Water For Mixing Concrete

Sea Water In Mixing Of Concrete?

          As we know Sea water not helpful and useful in construction also for drinking purposes 
here discussed about that sea water helpful in mixing of concrete for PCC.
     Sea water has a salinity of about 3.5 per cent. In that about 78% is sodium chloride and 15% is chloride and sulphate of magnesium. Sea water also contain small quantities of sodium and potassium salts. This can react with reactive aggregates in the same manner as alkalies in cement. Therefore sea water should not be used even for PCC if aggregates are known to be potentially alkali reactive. It is reported that the use of sea water for mixing concrete does not appreciably reduce the strength of concrete although it may lead to corrosion of reinforcement in certain cases. Research workers are unanimous in their opinion, that sea water can be used in un-reinforced concrete or mass concrete. Sea water slightly accelerates the early strength of concrete. But it reduces the 28 days strength of concrete by about 10 to 15 per cent. However, this loss of strength could be made up by redesigning the mix. Water containing large quantities of chlorides in sea water may cause efflorescence and persistent dampness. When the appearance of concrete is important sea water may be avoided. The use of sea water is also not advisable for plastering purpose which is subsequently going to be painted.
    Divergent opinion exists on the question of corrosion of reinforcement due to the use of sea water. Some research workers cautioned about the risk of corrosion of reinforcement particularly in tropical climatic regions, whereas some research workers did not find the risk of corrosion due to the use of sea water. Experiments have shown that corrosion of reinforcement occurred when concrete was made with pure water and immersed in pure water when the concrete was comparatively porous, whereas, no corrosion of reinforcement was found when sea water was used for mixing and the specimen was immersed in salt water when the concrete was dense and enough cover to the reinforcement was given. From this it could be inferred that the factor for corrosion is not the use of sea water or the quality of water where the concrete is placed. The factors effecting corrosion is permeability of concrete and lack of cover. However, since these factors cannot be adequately taken care of always at the site of work, it may be wise that sea water be avoided for making reinforced concrete. For economical or other passing reasons, if sea water cannot be avoided for making reinforced concrete, particular precautions should be taken to make the concrete dense by using low
water/cement ratio coupled with vibration and to give an adequate cover of at least 7.5 cm.
The use of sea water must be avoided in prestressed concrete work because of stress corrosion
and undue loss of cross section of small diameter wires. The latest Indian standard IS 456 of 2000 prohibits the use of Sea Water for mixing and curing of reinforced concrete and prestressed concrete work. This specification permits the use of Sea Water for mixing and curing of plain cement concrete (PCC) under unavoidable situation..

         It is pertinent at this point to consider the suitability of water for curing. Water that contains impurities which caused staining, is objectionable for curing concrete members whose look is important. The most common cause of staining is usually high concentration of iron or organic matter in the water. Water that contains more than 0.08 ppm. of iron may be avoided for curing if the appearance of concrete is important. Similarly the use of sea water may also be avoided in such cases. In other cases, the water, normally fit for mixing can also be used for curing.