Foundation

The lower part of a structure that transmits the load of the superstructure and also its own weight to the soil or rock ,is call Foundation 

Types of foundation

The various types of foundation are as detailed below

1. Footings : the direct bearing foundation which is constructed as a spread undar the base of a wall , is called a footing 
2. Combined footings : the combination of two or more footings jointed together to form a small mat , is called a combined footing. 
3. Strip foundations : the Foundation whoes length is considerable greater then its width is called a strip or continuous footing 
4. Raft foundation : the Foundation which supports a large number of loads of a singal unit of covers the whole loaded area even more , is called a raft foundation .
5. Pile foundation : the Foundation which is provided in soils incapable to transmit the structural load to suitable stretum by inserting relatively slender structural elements called piles, is khown as pile foundation                                                                       

• End bearing piles : the piles which act as columns and transmit the load through weak soil to firm stratum at a greater depth , are called end bearing piles
• Friction piles : the pile which carry the structural load  by the friction between the surfaces of the piles and the surrounding soil , are called friction piles
• Compaction piles : the friction piles which are driven Into cohesionless soils for increasing the shear strength of the soils by compaction, are called compaction piles.

Compressive strength test

• Cement, fine aggregate and coarse aggregate (up to 38) to be used for making concrete are weighed in the ratio to be used in the field and are of hand mixing or by machine mixing            
• Now water is added and the entir batch mixed until the concrete appears to be homogeneous and has the desired consistency test specimens recommend are 150×150×150 mm cubes or cylinders of 150 diameter and 150 mm height 
• Mixed concrete is filled into the  mould in layers of 50 mm and each layer is tamped with 16 mm in diameter and 600 mm long 35 times or with a vibrator  
• Test specimens are stored at a temperature 27+-3 °c at 90% humidity for 24+_1/2 hour form the time of addition of water to the dry ingredients 

• the After this time specimens are removed  from the moulds and placed in water and kept there until taken  out just before the test     

                • usually specimens are tested for 7 day  or 28 day  strength but IS code only suggest 28                         days strength only
                • specimen is placed between the plates of the compression testing machine with the care
                 that the axis of specimen is aligned with the cantre of thrust of the spherically seated plate
               • compression testing machine should be able to apply gradual load of 14 N/ mm 2 / minute                    until the specimen is crushed.
              • Average of the three values is taken as the compressive strength of concrete , provided the                 individual variation is not more than +- 15 per cent of the average

              NOTE- iS IS cade also recommends use of cubes of size 100×100×100 mm provided the                                   aggregate size does not exceed 19 mm

Field tests for cement

• Following four field tests may be carried out to ascertain roughly the quality of cement

1. colour : colour of cement should be uniform i.e. grey colour  with a light greenish shade  
2. Physical Properties : cement should fell smooth when touched or rubbed in between gingers 

• if it is felt rough ,it indicates adulteration with sand 
• if hand is inserted in a beg or heap of cement , it should  feel cool and not warm 
• if small quantity of cement is thrown  in a bucket of water , it should sink and should not float on the surface 
• A thin paste of cement with water should feel sticky between the fingers 
• if the cement contains too much of pounded clay and silt as an adulterant , the paste will give an earthy smell 

       3 :Persence of lumps : cement should be free form any hard lumps . such lumps are formed by                  the absorption of moisture form the atmosphere 

            . Any bag of cement containing such lumps should be rejected .

        4: Strength : strength of cement can be roughly ascertained in the following ways 

     

        (a) Briquettes with a lean or weak mortar are made . Size of briquettes may be about 75 mm* 25               mm*12 mm .The proportion of cement and send may be 1:6 .The briquettes are immersed in               water for a period of 3 days. if cement is of sounds quality , such briquettes will not be                         broken easily and it will be difficult to convert them into powder form

        (b)  A block of cement 25 mm *25 mm and 200 mm long is prepared and it is immersed for 7                     day  in water , it is then placed on supports 150mm apart and it is loaded with a weight of                     340 N  . The block should not show signs of failure

OPERATIONS INVOLVED IN THE MANUFACTURE OF BRICK

Brick making involves the following operations:

1. Preparation of clay:- Good brick earth, a mixture of pure clay and send alone with a small quantity of finely divided lime is first dug out, broken up, watered and kneaded well under feet till it becomes a homogeneous mass. The tempered earth is then covered up with mat pieces and allowed to dry gradually till it is just soft - enough for moulding .For manufacturing superior brick the clay is generally prepared by pug mills 

2. Moulding :- The well prepared clay is moulded in rectangular steel and wood moulds  without top and bottom, their longer sides project a few centimeters ti act as handles. Bricks are usually  moulded on a block of mood having a projection 6 mm deep and same length and breadth as the inside dimensions of the mould . moulding of bricks done on the stock board, is called  table moulding 

3. Drying:-  The moulded bricks are then allowed to dry so that these are sufficiently hard to be handled. when the bricks becomes sufficiently hard these are stacked . Eight or ten layers of bricks on edge with intervals of about one metre between them , are generally stacked 

4. Burning :- Well dried bricks are burnt in clamps or kinls to attain desired  crushing strength and also to impart red or yellowish colour.

TYPE OF CEMENTS

Following types of cement are generally used for various types of structures

1. Ordinary Portland cement
2. Low heat cement 
3. Rapid hardening Portland cement
4. Blast - furnace slag cement 
5. Sulphate resistant cement 
6. Air entraining cement 
7. White and coloured cement 

In addition to about, the following types of cements are also available

1. High alumina cement 
2. Pozzolana cement 
3. Oil well cement 

WATER DEMAND

In fact the fist requirement is to consider the demand ,and the second requirement is to find sources to fulfill that demand 

various type of water demand

• Domestic water demand -55 to 60% of total water consumption 
• Industrial water demand-50 mp
• Institutional and commercial water demand -20 lpcd 
• Demand for public use -10 lpcd 
•  Fire demand -1 lpcd 
• Water required to compensate losses in wastes  and thefts -55 lpcd 
• As per IS 1172-1983 as well as National building code, the domestic consumption under normal conditions in an Indian city is expected to be around 135 liter/head/ day
• Demand  for public uses is generally taken as 10 l/h/day
• The ordinary per capital  consumption for industrial needs of a city is generally taken as 50  l/h/day
• On an average, per capita demand of  20 l/h/day is usually considered  to be enough to meet such commercial and institutional water requirements, although this demand may be as high  as 50 l/h/d for highly commercialised cities

WHAT IS CIVIL ENGINEERING

Civil engineering is a professional engineering discipline that deals with the design, construction ,and maintenance of the physical and naturally built environment including works such as road, building, ,airport, railway, pipeline,  sewerage system and etc....... 

 Civil engineering is traditionally broken into a number of sub -disciplines after military , and it is define to distinguish non -military engineering form military engineering .
                     
Civil engineering takes place in the public sector form municipal through to national governments, and in the private sector form individual homeowners through to international companies