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Monday, 12 February 2018

Basic Civil Engineering Tips you should be remembered while working on a construction site.

1. GRADE OF CONCRETE:

M5 – 1 : 4 : 8

M10 – 1 : 3 : 6

M15 – 1 : 2 : 4

M20 – 1 : 1.5 : 3

M25 – 1 : 1 : 2

2. CLEAR COVER TO MAIN REINFORCEMENT:

Footings : 50 mm

Raft Foundation (Top) : 50 mm

Raft Foundation (Bottom) : 75 mm

Raft Foundation (Side) : 75 mm

Beam : 25 mm

Strap Beam : 50 mm

Column :40 mm

Slab : 15 mm

flat Slab : 20 mm

Staircase : 15 mm

Retaining Wall : 20 – 25 mm


Water Retaining Structures : 2 0- 30 mm

Maximum water absorption by bricks – 20%

Compressive strength of common bricks – 3.5 N/mm2

Density Of Bricks- 1600-1920 Kg/m3

Minimum thickness of slab – 125 mm

Dimension tolerance for cubes – +2

Maximum free fall of concrete – 1.50 m

Lapping should not be used for the bars having larger dia than 36 mm.

Binding wire required for steel reinforcement – 8 kg per MT

3 samples should be taken for every 100 m2 in core cutting test.

Maximum chair spacing – 1 m.

Minimum dia should be used in dowels rod – 12 mm.

Hook for strriups (one side) – 9D

No. of strriups = (clear span/spanning) + 1

Length of main steel in cantilever anchorage – 69D.

Minimum no. of bars in square column – 4

Minimum no. of bars in circular column – 6

Minimum dia of main bars and distributors in the slab – 8 mm.

Maximum dia of main bars and distributors in the slab – 1/8 of slab thickness.

All reinforcement should be free from mill scales, loose rust, and coats of paints, oil or any other substances.

3. SETTING TIME:

Initial setting time should not be less than 30 minutes.

Final setting time should not be greater than 10 hours.

4. REQUIRED CURING DAYS:

Super sulfate cement – 7 days

Ordinary portland cement – 10 days

Cement with minerals and admixtures – 14 days.

5. SLUMP VALUE (IS-456):

Lightly reinforced concrete: 25 – 75 mm.

Heavily reinforced concrete: 75 – 100 mm.

Trench fill : 100 – 150 mm ( for in-situ & tremie).

6. CUBE SAMPLES:

1 – 5 m3 : 1 No.

6 – 15 m3 : 2 No..

16 – 30 m3 :3 No.

31 -50 m3 : 4 No.

Above 50 m3 : 4 + 1 no. of addition for each 50 m3.


1) What is the storage area of cement godown?

20 bags/Square meter of plan area

2) What is the valume of one bag of cement?

1.25 Cuft/ 0.035Cum

3) What is the density of cement ?

1440 Kg/Cum

4) what is the specific gravity of cement particles?

3.15

5) What is the surface area occupied one cement bag?

0.3 Square meter

6) What is the general fineness modules rang for sand?

2-  3.5

7) What is the tensile strength of mortar cubs in 1:3 Proportions for 3 days?

2.0N/mm sqm

8) What are the permissible limits of presence of sulphate as per  I S 456. -2000 ?

2000mg/I for PCC works and 500mg /I for RCC works

9) What are the recommend slump values of general RCC works at site?

80 - 180

10) If there are 5% voids in concrete what is the reduction in strength of concrete?

30%

Some useful measurements
➡1cm = 10mm
➡1mitre = 100cm
➡1Km = 1000mitres
➡1kg = 1000grams
➡1gram= 1000milligram(mg)
➡1Quintal = 100Kg
➡1Metric ton = 1000Kg
➡1Pound = 454gm
➡1litre = 1000ml
➡1kilo litre=1000litres
➡1Gallon = 3.79litres
➡1Barrel oil= 163.65litres
➡1cusec = 1 cubic feet of water flows through a point in one second( this measure used only for flowing water)
➡1TMC = 100 crore cubic feet water(this measure used only for reserved water)
➡1 inch = 2.54cm
➡1 feet =12 inch= 30.48cm
➡1Yard(గజము)= 3feet
➡1mile = 1.609 km
➡1Natical mile=1.852km
➡1 cent= 435.6 sq feet
➡1acre = 100 cents
➡1Hectare = 2.471 acres
➡1kilo byte(KB)=1024bytes
➡1Megabyte(MB)=1024KB
➡1Gigabyte(GB)=1024MB
➡1Terabyte(TB)=1024GB
➡1Million=10 Lakhs
➡1Billion=1000 Million= 100 crore
➡1 Trillion= 1000 Billion=1Lakh crore
➡1 Karat = 4.16 '/. gold
➡24 karat gold=99.5 '/. gold(pure gold)
➡22 karat gold= 91.6 '/. gold + 8.4 '/. other metal Normally this 22 Karat gold is called as 916, KDM, HALL MARK
➡18 Karat gold=75 '/. gold+25 '/. other metal
➡12 karat gold = 50 '/. gold+ 50 '/. other metal
➡1 Ream = 500 papers
➡1gross = 12 dozen = 144 articles

Important  Information to be kept for Record.:
1 Gunta = 121 Sq yards.
1 Gunta = 101.171 Sq Meter.
1 Gaj = 1 Yard
1 Yard = 36 inch
1 Yard = 3 feet
1 Yard = 0.9144 meter

1 sq Yard = 0.83612 Sq meter.
1 sq Yard = 9 sq feet.
1 Sq yard = 1296 Sq inch.
1 Meter = 1.0936 Yards.
1 Meter = 39.370 inch.
1 Meter = 3.280 feet.
1 Sq meter = 1.1959 Sq yard.
1 Sq meter = 1550 Sq inch.
1 Sq Meter = 10.763 Sq feet.
1 feet = 0.304 meter.
1 feet = 0.333 yards.
1 feet =12 inch
1 Sq feet = 0.111 Sq Yard.
1 Sq feet = 0.09290 Sq Meter.
1 Sq feet = 144 Sq inch.
1 inch = 2.54 vv
1 Inch = 0.0254 meter.
1 Inch = 0.0277 yards.
1 Inch = 0.0833 feet.
1 Sq Inch = 0.00064516 Sq Meter.
1 Sq Inch = 0.0007716 Sq Yards.
1 Sq Inch = 0.00694444 Sq feet.
1 Acre = 4046.86 Sq Meter.
1 Acre = 4840 Sq yards.
1 Acre = 43560 Sq feet.

DEFINATIONS

Q. What is the soil?
Ans. Soil is commonly consisting of a naturally occurring loose or soft deposit part of earth’s crust, produced as a result of weathering or decompositioning of rock formation or decay of vegetation intermingled together.

Q.What is the Liquid limit?
Ans.The minimum water content at which the soil will flow under the application of a very small shearing force. (OR)
Water content at which soil passes from plastic to liquid state.

Q.What is Plastic limit?
Ans.Plastic limit is the moisture content at which a soil when rolled into a thread of smallest diameter of 3mm starts crumbling.

Q.What is the Plasticity index?
Ans.Plasticity index of a soil is the difference between its liquid limit and its plastic limit.
This gives an idea about the clay content in the soil, plasticity index increase with clay contents

Q.What is shrinkage limit?
Ans.Shrinkage limit gives an idea about the shrinkage or swellings characters of the soil, which may likely to occur in the soil after being compacted. A compacted soil of this type may shrink on draying and may swell again in contact with moisture.

Q.What do you mean by group index and how it is determined?
Ans.It is an empirical value used to evaluate the kind or type of soil to be used for sub-grade material. It can be determined by the equation
G.I = (F-35) [0.2+0.005 (L.L – 40)] + 0.01 (F-15) (P.I-10)
Here! F = Passing %ge on sieve # 200.

Q.What is S.P.T test?
Ans.This is the test, which carried out to know the bearing capacity of the soil. This is usually done on the foundation of bridges and huge buildings.

Q.What is CBR?
Ans. CBR is a measure of shearing resistance of the material under controlled density and moisture content.

Q.What is the “Optimum moisture content?
Ans.The moisture content at which the soil attains the max.dry density is called the optimum moisture content.

Q.What is the unit weight?
Ans.The relation ship between unit weight and acceleration due to gravity.

Q.What is the “Max. dry density”?
Ans.The dry density obtained using a specified amount of compaction at the optimum moisture content.



Q.What is the density?
Ans.It is defined as the mass per unit volume.

Q.What is the “Bulk density”
Ans.The mass of the material (including solid particles and any contained water) per unit volume including voids.

Q.What is the “Specific gravity”?
Ans.Specific gravity is the ratio of the weight of a given volume of a material at a given temperature to the weight of an equal volume of distilled water at that temperature.

Q.What is the “Absolute Specific gravity”?
Ans.It is the ratio of the weight of solid, referred to the vacuums to the weight of an equal volume of gas-free distilled water, both taken at a stated temperature.

Q.What is the “Apparent specific gravity”?
Ans.It is the ratio of the weight of aggregate dried in oven at 100 to 110ºC for 24 hours to the weight of water occupying a volume equal to that of the solid including the impermeable pores.

Q.What is the “Effective specific gravity”?
Ans. Considered the overall volume of the aggregate exclusive of the volume pores that absorb the asphalt cement.

Q.What is compaction?
Ans.Compaction is a mechanical process of volume reduction by packing together the soil particles. Rolling, ramming and vibration with water accomplish it and there are decreases in volume of air voids.

Q.What do you determine the shear strength of soil?
Ans. By Tria-axial Test:
The basic principal is that a cylindrical soil specimen is first encased in a thin rubber membrane and subjected to fluid pressure around the cylindrical surface, the lateral pressure is held constant while an axial load is applied and in around until failure occurs.

Q.What is the permeability and its significance?
Ans.It is the hydraulic property of soil, which indicates the case with which fill water flow through the same mass. It is the significant on numerous.

Submitted by-Nikhil Lingayat

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