Monday, 19 December 2016

Thursday, 28 July 2016

What is Bill of quantity ?

Bill of quantity is the one document that contains all the quantity in cum which come from the building drawings.

Also the rate of one cum is calculate from the RATE ANALYSIS.

On my website I put the rate analysis files in excel format with the video.

Bill of quantity is finally used to estimate the total cost with what quantity require for the particular project.

It's really very important to list all the items in the BOQ.

The rate estimate from the rate analysis is put in the BOQ and that multiply with the total quality of particular item of building.

I put some BOQ sample photos with there format on my website u can check that in download tab over top of the website.

It is really important to know about the BOQ and RATE ANALYSIS then u can be successful in the analysis of rates of building.

Wednesday, 27 July 2016

Mixing of concrete

To produce uniform and good concrete, it is necessary to mix cement, sand and coarse aggregate, first in dry condition and then in wet condition after adding water.

The following methods are practiced:
(a) Hand Mixing
(b) Machine Mixing.

Compaction of Concrete

In the process of placing concrete, air is entrapped.

The entrapped air reduces the strength of concrete up to 30%. Hence it is necessary to remove this entrapped air.

This is achieved by compacting the
concrete after placing it in its final position.

Compaction can be carried out either
by hand or with the help of vibrators.

PROPERTIES OF CONCRETE

The properties of green concrete include:
1. Workability
2. Segregation
3. Bleeding
4. Harshness.
The properties of hardened concrete are:
1. Strength
2. Resistance to wear
3. Dimensional changes
4. Durability
5. Impermeability.

PROPERTIES OF 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.

BRICKS

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 withhand moulding, sun drying and burning in clamps. A considerable amount oftechnological development has taken place with better knowledge about to propertiesof 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 commonlyused in India.

DISADVANTAGE OF BRICKS MASONARY OVER STONE MASONARY


1. Strength of brick masonry is less than that of stone masonry.
2. Durability of brick masonry is less.
3. Brick masonry needs plastering and plastered surface needs colour washing.
Stone masonry don’t need them and hence maintenance cost is more in brick
masonry.
4. Brick masonry absorbs water and there are possibility of dampness. There is no
such problem in stone masonry.
5. More architectural effects can be given in stone masonry compared to that in
brick masonry.
6. Stone masonry gives massive appearance and hence monumental buildings are built in stone masonry.

ADVANTAGE OF BRICKS MASONARY OVER STONE MASONARY


1. Since shape and size of bricks are uniform, it do not need skilled labour for the
construction.
2. Bricks are light in weight and hence handling them is easy.
3. Bricks are easily available around cities and their transportation cost is less
because their weight is less. Stones are to be brought from quarries which are
located only at few places.
4. It is possible to use all types of mortar in brick masonry. For unimportant
buildings even mud mortar can be used.
5. Thinner walls can be constructed with bricks but it is not so with stones.

Monday, 18 July 2016

Long wall and Short wall method notes by Parag K Pal.

Long wall and Short wall method is a estimation and coasting method. This method is mostly use for load bearing structure. It really very simple method just download the notes below and watch the following video lecture so you can simply learn this method.


                                               DOWNLOAD


Watch the lecture on the long wall and short wall method.


Civil Engineering Projects

1)  Prefabricated building with EPS wall panels by Parag K Pal.



Saturday, 16 July 2016

Civil Engineering Project Topic

Earthquake Resistant Design And Construction

Light Weight Concrete

Heavy Density Concretes

Self Compacting Concrete

Instant Concrete Road Repair Solution

Advanced Earthquake Resistant Techniques

smart materials

Causes Prevention And Repair of Cracks In Building

Advanced Pavement Design

sewage treatment plant

Air pollution & its control

stability of high rise buildings

watershed management

Bandra-Worli Sea Link

Concrete Cube Testing

Cellular Lightweight Concrete

Bridge Bearings & Stability

Development Of Remote Monitoring System

the rain roof water-harvesting system

pile foundation

seismic isolation devices

formwork types & design

green buildings

zero energy buildings

construction challenges for bridges

Construction Equipments

Offshore structures.

Geo Synthetic

Sand witched Panel

Replacement Of Sand By Quarry Dust In Concrete

Load Bearing Capacity Of Un-reinforced Brick Masonry

Brick Masonry Strength

Cement Composite With No-Fines Concrete

Study Of Road Humps

Low Cost Roofing Tiles

Partial Replacement Of Cement By Red Mud In Mortar

The Strength Behaviour Of Fly Ash Bricks

Studies On Bamboo Reinforced

Low Cost Bricks Making

Crushed Stone Dust Cement Blocks

Geotextiles Reinforced Soil For Pavements

Flyash Mosaic Flooring Tiles

Domestic Water Treatment Plant

Electrical Resistivity Survey For Ground Water Exploration

Flexible And Rigid Pavement

Fiber Reinforced Concrete

Utilization Of Silica Fume In Concrete

Fly Ash Concrete

silica fume concrete

glass fiber reinforced concrete

flexible pavement

fly-ash concrete pavement

eco- friendly housing


Friday, 17 June 2016

Slope deflection method sway portal frame numerical probleam

Analysis the portal frame shown in following fig. by Slope deflection method and draw bending moment diagram.


Answer:-

Slope deflection method is help to determine the bending moment of sway portal frame.

Step 1:-  At fixed support the angle is zero i,e it and the deflection in beam as a delta is shown in fig. All loads are applied on it.





Step 2:- Very 1st the calculation of fixed end moment is determine by using simple fixed end formulas. And the sign convension are placed -ve & +ve respectively.

Wednesday, 15 June 2016

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 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.

PLASTERING


Applying mortar on the surfaces of walls, columns, ceiling etc. to get smooth finish is termed as plastering.

Mortar used for plastering may be lime mortar, cement mortar or lime-cement mortar.

Lime mortar used lime to sand ratio of 1 : 3 or 1 : 4.

Cement mortar of 1 : 4 or 1 : 6 mix is very commonly used for plastering, richer mix being used for outer walls.

CELLULAR CONCRETE


It is a light weight concrete produced by introducing large voids in the concrete or mortar. Its density varies from 3 kN/m3 to 8 kN/m3. It is also known as aerated, foamed concrete.

Properties of cellular concrete
1. It has low weight.

2. It has good fire resistance.

Compaction factor test.


This is another test to  identify the workability of concrete. This test is conducted in the laboratory.

The test equipment consists of two hoppers and a cylinder fixed to a stand, the dimensions and the distances between the three vessels being standardized. Vessel A and B are having hinged bottoms whereas cylinder C is having fixed bottom.

What is uses of timber?


1. For heavy construction works like columns, trusses, piles.

2. For light construction works like doors, windows, flooring and roofing.

3. For other permanent works like for railway sleepers, fencing poles, electric poles and gates.

4. For temporary works in construction like scaffolding, centering, shoring and strutting, packing of materials.

What is CEMENT & its Chemical properties


Cement is a commonly used binding material in the construction. The cement is obtained by burning a mixture of calcarious and argillaceous material at a very high temperature and then grinding the clinker so produced to a fine powder.

It was first produced by a mason Joseph  Aspdin in England in 1924. He named it as portland cement.

#Chemical properties of ordinary portland cement.

What are the common building stones?


(i) Basalt and trap

(ii) Granite

(iii) Sand stone

(iv) Slate

(v) Quartzite.

(vi) Marble

Uses of Stones.


(i) Stone masonry is used for the construction of foundations, walls, columns and arches.

(ii) Stones are used for flooring.

(iii) Stone slabs are used as damp proof courses, lintels and even as roofing materials.

What are the Properties of Stones?


(i) Structure

(ii) Texture

(iii) Density

(iv) Appearance

What is stone ?


Stone is a ‘naturally available building material’ which has been used from the early age of civilization. It is available in the form of rocks, which is cut to required size and shape and used as building block. It has been used to construct small residential buildings to large palaces and temples all over the world.

A. Type of Stones

• Geological   • Physical    • Chemical

Tuesday, 7 June 2016

DETERMINATION OF MOISTURE CONTENT


OBJECTIVE 

Determine the natural content of the given soil sample.  

NEED AND SCOPE OF THE EXPERIMENT

In almost all soil tests natural moisture content of the soil is to be determined. The knowledge of the natural moisture content is essential in all studies of soil mechanics. To sight a few, natural moisture content is used in determining the bearing capacity and settlement. The natural moisture content will give an idea of the state of soil in the field. 

DEFINITION

The natural water content also called the natural moisture content is the ratio of the weight of water to the weight of the solids in a given mass of soil. This ratio is usually expressed as percentage.

APPARATUS REQUIRED

    1. Non-corrodible air-tight container.       2. Electric oven, maintain the temperature between 1050 C to 1100 C.      3. Desiccator.      4. Balance of sufficient sensitivity. 

PROCEDURE

1. Clean the container with lid dry it and weigh it (W1).  2. Take a specimen of the sample in the container and weigh with lid (W2).  3. Keep the container in the oven with lid removed. Dry the specimen to constant weight maintaining the temperature between 1050 C to 1100 C for a period varying with the type of soil but usually 16 to 24 hours.  4. Record the final constant weight (W3) of the container with dried soil sample. Peat and other organic soils are to be dried at lower temperature (say 600 ) possibly for a longer period. 

  Certain soils contain gypsum which on heating loses its water if crystallization. If itb is suspected that gypsum is present in the soil sample used for moisture content determination it shall be dried at not more than 800 C and possibly for a longer time.

OBSERVATIONS AND RECORDING

Data and observation sheet for water content determination  

S.No. Sample No. 1 2 3

1 Weight of container with lid W1 gm

     

2 Weight of container with lid +wet soil W2 gm

     

3 Weight of container with lid +dry soil W3 gm

     

4 Water/Moisture content

W = [(W2−W3)/(W3−W1)]100

     

   

  RESULT

The natural moisture content of the soil sample is ________ 

 REMARKS

1. A container with out lid can be used, when moist sample is weighed immediately after placing the container and oven dried sample is weighed immediately after cooling in desiccator.

2. As dry soil absorbs moisture from wet soil, dried samples should be removed before placing wet samples in the oven.

Monday, 6 June 2016

Self compacting concrete.


A concrete which is capable to compact itself by its own self-weight under gravity without any external efforts like vibration is called as self compacting concrete. the mix is required to have ability of passing, filling and being stable.

Following ingredient are used to prepare self compacting concrete.

1. cement :- OPC 43 or 53 grade.

2. Aggregates:- well grade rounded or cubical aggregate of size 10 to 20mm uniformly graded fine aggregates.

3. Good quality of mixing water.

4. Super plasticizer like poly-carboxylated ether to improve the workability and viscosity modifying agent.

5. Mineral admixture like fly ash, ground granulated blast furnace slag, silica flume, fiber, finely crushed lime stone, dolomite or granite

6. Under self weight , scc should level and deform itself without any compaction and external vibration. There should be not be any entrapped air in concrete.

7. SCC should be fully flowable but without segregation and bleeding. This is achieved by keeping higher viscosity of cement and mortar to ensure flowability while maintaning no sedimentation of bigger aggregates.

What do you mean by Maturity of concrete ?


It is not only the time but also the temperature during the early period of hydration that influence the rate of gain of strength of concrete. since the strength development of concrete depends on both time and temperature it can be said that strength is a function of summation of product of time and temperature.

This summation is called maturity of concrete.

Maturity = ∑ (time X temperature)

What is membrane curing?


Sometimes, concrete works are carried out in places where there is acute shorting of water. the lavish application of water for water curing is not possible for reason of economy.

It has been pointed out earlier that curing does not mean only application of water, it means also creation of condition for promotion of uninterrupted and progressive hydration.

Membrane curing is a good method of maintaining a satisfactory state of wetness in the body of concrete to promote satisfactory state of wetness in the body of concrete to promote condition hydration when original water/cement ratio used is not less that 0.5. to achieve best result, membrane is applied after one or two days of actual wet curing.

Since no replenishing of water is done after the membrane has been applied it should be ensure that the membrane is of good quality and it is applied effectively. two or three coats may be requires for effective sealing of the surface to prevent the evaporation of the water.

when water proofing paper or polyethylene paper are used care must be taken to see that these are not punctured anywhere and also whether adequate lapping is given at the junction and this is effectively sealed.

Water curing


This is by far the best method of curing as it satisfies all the requirements of curing, namely, promotion of hydration, elimination of shrinkage and absorption of the heat of hydration. it is desirable that a certain extent of water curing is done before the concrete is covered with membranes. water curing can be done in following ways:-

1. Immersion

2. Ponding

3. Spraying

4. Wet covering

the precast concrete items are normally immersed in curing tanks for a certain duration. pavement slabs, roof slabs etc. are covered under water by making small  ponds. vertical retaining wall or plastered surfaces or concrete column etc. are cured by spraying water. In some cases, wet covering such as wet gunny bags, hessian cloth, jute matting, straw etc. are wrapped to vertical surface for keeping the concrete wet. for horizontal surfaces saw dust, earth or sand are used as wet covering to keep the concrete in wet condition for longer time so that the concrete is not unduly dried to prevent hydration.

Curing


The process of maintaining a satisfactory moisture content and a favorable temperature in concrete during the period immediately following placement so that hydration of cement may continue until the desired properties are developed to a sufficient degree to meet the requirement of service is called curing of concrete.

curing methods may be divided broadly into four categories:-

1. water curing

2. membrane curing

3. Application of heat

4. Miscellaneous

 

Slump Test


Slump test is the most commonly used method of measuring workability of concrete. the apparatus for conducting the slump test essentially consists of a metallic mould in the form of a frustum of a cone having the internal dimensions as follows:-

Bottom diameter   20cms

Top diameter          10cms

Height                      30cms

The mould is the place on a smooth, horizontal, rigid and non absorbent surface. the mould is then filled in four layer each approximately 1\4 of the mould. each layer is tamped 25 times by the tamping rod taking care to distribute the stroke evenly over the cross sections. After the top layer has been rodded, top is struck off level with a trowel and tamping rod. the mould is removed from the concrete immediately by raising it slowly and carefully in a vertical direction. this allows the concrete to subsidence. this subsidence is referred as slump of concrete. the difference in level between the height of the mould and that of the height point of the subsided concrete is measured. this difference in height in mm is taken as slump of concrete.

slump requirement for beams and slabs 50mm to 100mm

for walls and columns 75mm to 100mm

Vibrated concrete 15mm to 25mm  

what are the partial properties of workability ?


Mixability, Transportability, Mouldability and Compactibility are the partial properties of workability.

a)  Mixability:-

It is the ability of the mix to produce a homogeneous green concrete from the constituent materials of the batch, under the action of the mixing forces

b) Transportability:-

Transportability is the capacity of the concrete mix to keep the homogeneous concrete mix to keep the homogeneous concrete mix from segregating during a limited time period of transportation of concrete.

c) Mouldability:-

It is the ability of the fresh concrete mix to fill completely the forms or moulds without losing continuity or homogeneity under the available techniques of placing the concrete at a site.

d) Compactibility:-

Compactibility is the ability of concrete mix to be compacted into a dense, compact concrete, with minimum voids, under the existing means of compaction at the site.

What is Workability of concrete ?


The ease with which the concrete can be mixed up with minimum quantity of water, transported, placed and compacted without segregation and bleeding is called workability.

Workability is defined as the property of concrete which determines the amount of useful internal work necessary to produce full compaction. workability concrete is one which exhibits very little internal friction between particle and particle.

The factor helping concrete to have more lubricating effect to reduce internal friction are as follows:-

a. water content

b. mix proportion

c. size of aggregate

d. surface texture

d. shape of aggregate

f. grading of aggregate

g. use of admixture.

Tuesday, 31 May 2016

Standard Penetration Test (SPT)


One of the most common in-situ tests is the standard penetration test or SPT. This test which was originally developed in the late 1920s.

SPT is most commonly used in situ test, especially for cohesionless soils which cannot be easily samples. the test is extremely useful for determining the relative density and the angle of shearing resistance of  for cohesionless soils.

it can also used to determine the unconfined compressive strength of cohesive soils.

The standard penetration test is conducted in a borehole using a standard split-spoon sampler. 

When the borehole (55 to 150 mm in dia) has been drilled to the desired depth, the drilling tools are removed and the split-spoon sampler, attached to standard drill rods of required length is lowered to the bottom of the borehole and rested at the bottom.

The split-spoon sampler is then driven into the soil for a distance of 450 mm in three stages of 150 mm each by blows of a drop hammer of 63.5 kg mass falling vertically and freely through a height of 750 mm at the rate of 30 blows per minute (IS 2131 – 1981). The number of blows required to penetrate every 150-mm is recorded while driving the sampler. If full penetration is obtained, the blows for the first 150 mm is retained for reference purposes, but not used to compute the SPT value because the bottom of the boring is likely to be disturbed by the drilling process and may be covered with loose soil that may fall from the sides of the boring. The number of blows required for the next 300 mm of penetration is recorded as the SPT value. The number of blows is designated as the “Standard Penetration Value” or “Number” N.

The slit-spoon sampler is then withdrawn and is detached from the drill rods. The split barrel is disconnected from the cutting shoe and the coupling. The soil sample collected inside the split barrel is carefully collected so as to preserve the natural moisture content and transported to the laboratory for tests. Sometimes, a thin liner is inserted within the split-barrel so that at the end of the SPT, the liner containing the soil sample is sealed with molten wax at both its ends before it is taken away to the laboratory. 

Precautions

The drill rods should be of standard specification and should not be in bent condition

The split spoon sampler must be in good condition and the cutting shoe must be free from wear and tear

 The drop hammer must be of right weight and the fall should be free, frictionless and vertical.

 The height of fall must be exactly 750 mm. Any change in this will seriously affect the N value.

 

The standard penetration number is corrected for dilatancy correction and overburdon correction.

Undisturbed soil samples


Undisturbed soil samples are those in which the in-situ soil structure and moisture content are preserved.

• They are representative and also intact

• These are used for consolidation, permeability or shear strengths test (Engineering properties)

• More complex jobs or where clay exist

• In sand is very difficult to obtain undisturbed sample

• Obtained by using Shelby tube (thin wall), piston sampler, etc., 

Disturbed soil samples


Disturbed soil samples are those in which the in-situ soil structure and moisture content are lost, but the soil particles are intact.

• They are representative 

• They can be used for grain size analysis, liquid and plastic limit, specific gravity, compaction tests, moisture content, organic content determination and soil classification test performed in the lab

 • e.g., obtained through cuttings while auguring, etc.

Depth of exploration


The depth of the exploration required at a particular site depend on the degree of variation of the sub-surface data in the horizontal and vertical directions. It is not possible to fix the number, disposition and depth of borings without making a few preliminary borings or sounding at the site.

Generally exploration should be carried out to a depth upto which the increase in pressure due to structural loading is likely to cause perceptible settlement or shear failure. such a depth known as the significant depth, depent upon the type of the structure, its weight.  It is generally safe to assume the significant depth upto a level at which the net increase in vertical pressure become less than 10% of the initial overburden pressure.

Stages of the sub-surface exploration


1. Reconnaissance

site Reconnaissance is the 1st step in the exploration. it include a visit to the site and to study the maps and other relevant records. it helps in deciding the future programme of the site investigation. types of sample adopted to be taken and the laboratory testing and in-situ testing.

2. Preliminary or general exploration

the aim of the general exploration is to get an approximate picture of the sub-soil condition at the relatively low cost. the information so obtained should suffice for the design and execution of minor and routing engineering works.

the preliminary exploration are generally in the form of few borings or test pits. test are conducted inthe form of the borings or test pits. test are conducted with cone penetrometers and sounding rods to obtain information about strength and compressibility of the soil

3. Detailed exploration

it is a supplement to general exploration when large engineering works, heavy loads and complex costly foundation are involved, such as bridge, dam, and multistory building. however for small projects especially at sites where the strata are uniform, detailed exploration may not be required.

the purpose of detailed exploration is to determine the engineering properties of the soils in different strata. it include the  extensive boring programme, sampling and testing of the samples in the a laboratory.

field test, vane shear test, plate load test and permeability test are conducted to determine the properties of the soil in natural state.

the test for the determination of the dynamic properties are also carried out.

 

what is a Scope of soil investigation ?


An investigation of the site is essential for judging its suitability for the purposed engineering works and for preparing adequate and economic design. it consists of determining the profile of natural soil deposits at the site taking the soil samples and determining the engineering properties of the soils. It also include the in-situ testing of the soil.

1. to select the type and depth of the foundation for a given structure.

2. to determine the bearing capacity of the soil.

3. to estimate the probable maximum and differential settlement.

4. to predict lateral earth pressure against retaining walls and abutments.

5. to select the construction techniques.

6. to select the safety of the existing structure and to suggest the remedial measures.

Objectives of soil exploration


soil exploration is very useful for civil engineer to execute the design of construction, planning of construction, and for following purposes.

1. To know the geological condition of rock and soil formation.

2. To establish the groundwater levels and determine the properties of water.

3. To select the type and depth of foundation for proposed structure

4. To determine the bearing capacity of the site.

5. To estimate the probable maximum and differential settlements.

6. To predict the lateral earth pressure against retaining walls and abutments.

7. To select suitable construction techniques

8. To predict and to solve potential foundation problems

9. To ascertain the suitability of the soil as a construction material.

10. To determine soil properties required for design

11. Establish procedures for soil improvement to suit design purpose

12. To investigate the safety of existing structures and to suggest the remedial measures.

13. To observe the soil the soil performance after construction.

14. To locate suitable transportation routes.

Tuesday, 2 February 2016

Moment Distribution Method Portal Frame Numerical

In this video i completely explained the procedure for solving the MDM of portal frame. This method is very important for analysis of any building. We can solve this method by fallowing steps:-

1_ Determination of Fixed End Moments
2_ Determination of stiffness factor
3_ Determination of Distribution factor
4_ Solving sway and non sway MDM table to get joints moments
5_ Determination of sway correction factor
6_Simple bending moments
7_Final bending moments diagram

                                      Watch the video to learn Moment Distribution Method


Sunday, 24 January 2016

Different types of the soil samples


The soil samples can be of two types:-

1) A disturbed sample

2) Undisturbed sample

 

1) A disturbed sample is that in which the natural structure of soil get partly or fully modified and destroyed although with suitable precautions the natural water content may be get preserved.

such a sample however be representative of the natural soil by maintaining the original proportion of various soil particle impact.

it can be used to determine the  index properties of the soil. Such as grain size, plasticity characteristics specific gravity.

however it is impossible to get truly undisturbed sample. some disturbance is inevitable during sampling even when almost care is taken. even the removal of the sample from the ground produces a change in the stresses and cause disturbance. it is used for determining the compressibility shear strength permeability shrinkage limit etc. the smaller disturbance the greater would be the reliability of the result.

 

2) An undisturbed sample is that in which the natural structure and properties remain preserved.

Negative skin friction

Negative skin friction is a downward drag acting on the pile due to downward movement of the surrounding compressible soil relative to the pile.

This happens when the surrounding, compressible soil has been recently filled of formed.

 AS the soil consolidates the earth filed moves downward developing the friction forces on the perimeter of the pile which tends to carry the pile further into the ground.

The negative skin friction may also be developed by lowering of the ground water the increase in effective stress causing consolidation of the soil, with the resulting settlement and friction force being developed on the pile.

Permeability


1) Is the ease with which water can flow through any medium.

2) In soil mechanics, permeability of soil is a soil property which describes quantitatively, the ease with which water flows through soil.

3) Permeability is a very important engineering property of soil.

4) Knowledge of permeability is essential in a number of soil engineering problems, such as settlement of buildings yield of wells, seepage through and below the earth structures. it control the hydraulic stability of soil masses.

5) The permeability of soil is also required in the design f filter used to prevent piping in hydraulic structures and subgrade drainage, rate of consolidation of composition of compressible soils and many other aspects.

Index properties of soil


Those properties which helps to access the engineering behavior of soil and which assist in determining its classification accurately are termed as the index properties. index properties include indices which help in determining the engineering behavior such as

1_ strength

2_ load-bearing capacity

3_ swelling and shrinkage

4_ settlement etc.

 

these properties may be relating to

1. individual soil grain

2. aggregate soil mass

The properties of individuals particles can be determined from the  remoulded, disturbed sample.

These depend upon the individuals grains there mineralogical composition size and shape of grain and are independent of soil formation.

The soil aggregates properties depend upon the mode of soil formation, soil history and soil structure. these properties should be determined from the disturbed sample or preferably from in situ test.

Saturday, 2 January 2016

Grade of concrete

Characteristic strength is defined us the strength of material below which not more than 5% of test results are expected to full. 

The concrete grade M10, M15 and M20 are termed as ordinary concrete and those of M25 to M55 are termed as standard concrete and the concrete of grade 60 and above are termed as high strength concrete. 

 The selection of minimum grade of concrete is dictated by durability considerations which are based on kind of environment to which the structure is exposed, though the minimum grade of concrete for reinforced concrete is specified as M20 under mild exposure conditions, it is advisable to adopt a higher grade.  

 For moderate, severe, very severe and extreme exposure conditions, M25, M30, M35 & M40 grades respectively are recommended.

Types of constructions


1 load bearing structure

2 framed structure

1) load bearing structure:- 

 1. in load bearing structures the entire load of the superstructure is transmitted through the walls to the soil below the ground. 

2. these walls are supported on continuous foundation that resist on hard strata. thickness of such walls is too large.

3. if the number of storey is increased the thickness of the wall increases.

4. this type of construction reduces the carpet area

5. this type of construction cannot be used for multi-storeyed building.

2.) framed structure

1. framed structure consists of a series of frame made up of beams and columns.

2. walls are constructed within the frames which are known as a partition walls

3. thus the load of floor roofs and partition walls are supported by beams which in turn transmit the load to the column.

4. column transmit the load to the foundation, which rests on a hard soil below the ground

5. framed structure are suitable for medium and multi storeyed building.

Types of loads


The basis requirement of any structural member  of building is that should be strong enough to carry or support all the possible type of load which acts on it.

1 dead

2live or imposed

3 impact

4 wind load

5 snow

6 earthquake

 1. dead load :-   dead load are permanent loads which are transferred to structural throughout the life span. the dead load in a building comprise the weight of roofs, floors, beams, columns, walls, partition walls etc

2. live load:- the load which keep on changing on time to time are called live loads. common example of such moving loads in a building re the weight of the person, weight of movable partition , weight of furniture's, home appliances, equipment etc. these loads are to be suitably assumed by the designer. it is one of the major loads in the design.

3. impact load:- it is caused by vibration or acceleration thus impact loads is equal to imposed loads incremented by some %. for ex, vibration of moving vehicle or machines

4 wind loads:- when wind is obstructed by the structure, it exerts a pressure on the structure known as wind pressure. wind pressure acts horizontally on the exposed vertical faces of the structure. wind loads is effective in case of tall buildings.

5. earthquake load:- earth causes horizontal and vertical ground shaking. the  horizontal and verticle shaking is usually most critical on building. every building and its portions should be designed and constructed to resist  the effect of earth ground motions.

6 Snow loads:- it acts on the roofs. roofs should be designed loads due to snow, whichever is more severe. for the building to be located in the regions wherever snow is likely to falls, this loads is to be considered. mountainous regions in northern parts of India are subjected to snow fall.

Basic function of building.


1. it should be sufficiently strong to withstand the effects of the atmosphere and environment.

2. it should be durable and stable to take up the anticipated loads coming on it including the self weight live load and earthquake load.

3. it should be well ventilated and free from dampness.

4. it should be resist penetration of moisture

5. it should be provide maximum living and working comfort

6. it should be dimensionally stable

7. grouping of rooms should be so planned as to ensure circulation and optimum utilization of space and maximum efficiency fire hazards.

8. the building should be safe against fire hazards

9. the building should be safe against theft and burglary the external wals should be made so strong to resist any such attempt.

10. the building should be sound insulating so as to reduce sound passing through it.

SELECTION OF SITE




For good planning and designing of building, the site of the building is the most important aspect. the fallowing general guidelines should be kept in mind while selecting a site for a building.

1 . SITE plot must be of clear title along with clear ownership rights of the land.

2. the building site should be located on a fully developed or fat developing locality.

3. for happy living the neighborhood should be of equal status in society.

4. the shape of the plot shall not be irregular

5. as far as possible rectangular plot should be selected because maximum area of plot can be used for construction.

6. the site should be have general facilities such as a sewer line,  water line, power construction, street lights, and garbage disposal.

7. the site should be well connected by road by pass and service lines.

8. the site should be elevated land so as to have easy surface drainage  of rain water

9. the ground water table level at the site should be not too high not too low.

10.the soil condition of plot should be such that economical foundation should be possible, good compact soil, hard strata, rock or sand is desirable at minimum depth.

11. the site should have good view of landscape such as hills, gardens, rivers, lake, seashore as to promote healthy and peaceful living.

12. the site should away from kilns, quarries, congested and noisy localities and such other places.