Must-Have Knowledge for Civil Engineers | Civil Basic Knowledge
We know the civil engineering line different work different parts of basic knowledge. So we are below points show.
1. Drawing Points to Remember for Civil Site Engineer
2. QA /QC Points to Remember for Civil Site Engineer
3. Billing / Site Points to Remember for Civil Site Engineer
Drawing Points to Remember for Civil Site Engineer
In civil line work required drawing for any work like
Types of Drawings
Plan Passing Drawing
Site Plan / Layout Plan
QA /QC Points to Remember for Civil Site Engineer
Quality assurance (QA) and quality control (QC) are two terms that are often used interchangeably. Although similar, there are distinct differences between the two concepts. This page will explain the differences between quality control and quality management, and provide definitions and examples of each.
1. Cube casting frequency
The minimum frequency of sampling of concrete of each grade shall be in accordance with the following:
|Quantity of Concrete in the Work, m3||Number of Samples|
|51 and above||4 Plush one|
|Additional sample for each additional 50 m3 or part thereof|
2. Dimension tolerance for cubes + – 2 mm.
3. Slump as per IS 456
Lightly reinforced 25 – 75 mm
Heavily reinforced 75 – 100 mm
Trench fill (insitu & Tremie) 100 – 150 mm (For Tremie no need of vibrator)
4. Various Density For site required
Brick=1682kg/cum or 1920kg/m3
Steel = 7850kg/m3
Water = 1000kg/m3
R.C.C = 2500kg/m3 (5% STEEL)
P.C.C = 2400kg/m3
Wood = 1100kg/ m3
Loose sand = 1442 kg / m3
Dry sand = 1602 kg / m3
Packed sand= 1682 kg / m3
Wet sand = 1922 kg / m3
Aggrgate = 1200-1750 kg / m3
5. Water absorption
Coarse Aggregates = Max water absorption limit for coarse aggregates in any climatic condition should not be more than 2%.
Fine Aggregates = Range varies from 0.3–2.5%. Max permissible limit of fine aggregates is 3%.
Brick = Water absorption shall not be more than 20% by weight up to class 12.5 and 15% by weight for a higher class.
6. Maximum Free fall of concrete allowed is 1.50 m
7. In soil filling as per IS code for every 100 m2 3 samples for core cutting tests should be taken.
8. Back Filling
Any back-filling shall be compacted 95% of dry density at the optimum moisture content and in layers not more than 200 mm for filling above structure and 300 mm for no structure.
9. Water Content Ratio
|Exposure||Plain Cement Ratio||Reinforced Cement Concrete|
|IS 10262||Minimum Cement Content||W/C Ratio||Grade||Minimum Cement Content||W/C Ratio||Grade|
10. Cement Stored
Cement shall be stored in dry places on a raised platform about 200mm above floor level and 300mm away from walls. Bags to be stacked not more than 10 bags high in such a manner that it is adequately protected from moisture and contamination.
11. Compressive Strength
|Grade of Concrete||Minimum compressive strength N/mm2 at 7 days||Specified characteristic compressive strength (N/mm2) at 28 days|
Classification of Bricks Based on Compressive Strength
The common burnt clay shall be classified on the basis of average compressive strength as given in table.
|Bricks Class Designation||Average compressive strength of Bricks|
|Not less than (N/mm2)||Less than (N/mm2)|
12. Concrete has Two setting types
Initial Setting time – 30 min
Final Setting time – 10 hrs
13. De-Shuttering time of different RCC Members
|RCC Member||De-shuttering time|
|For columns, walls, vertical form-works||16-24 hrs.|
|Soffit formwork to slabs||3 days (props to be refixed after removal)|
|Soffit to beams props||7 days (props to refixed after removal)|
|Beams spanning up to 4.5m||7 days|
|Beams spanning over 4.5m||14 days|
|Arches spanning up to 6m||14 days|
|Arches spanning over 6m||21 days|
14. Curing Period
The curing Period of RCC is 28days.
Billing / Site Points to Remember for Civil Site Engineer
1. Lap length
Note: Lapping is not allowed for the bars having diameters more than 36 mm.
Columns = 45 x d
Beams = 60 x d
Slabs = 60 x d
2. Chair Spacing for Bar Bending
Chair spacing maximum spacing is 1.00 m (or) 1 no per 1 m2.
3. Chairs a Minimum Dia in Bar Bending
Chairs a minimum of 12 mm diameter bars to be used.
4. Clear Cover to Main Reinforcement:
Footing Cover = 50 mm
Raft Foundation.top = 50 mm
Raft Foundation. Bottom/Sides = 75 mm
Strap Beam = 50 mm
Grade Slab = 20 mm
Column = 40 mm
Shear Wall = 25 mm
Beams = 25 mm
Slabs = 15 mm
Flat Slab = 20 mm
Staircase = 15 mm
Ret. Wall = 20/ 25 mm on Earth
Water Retaining Structures = 20/30 nn
5. Weight of Rod Per Meter Length:
6mm = 0.222Kg/m
8mm = 0.395 Kg/m
10mm = 0.616 Kg/m
12mm = 0.888 Kg/m
16mm = 1.578 Kg/m
20mm = 2.466 Kg/m
25mm = 3.853 Kg/m
32mm = 6.313 Kg/m
40mm = 9.865 Kg/m
6. Plaster Deduction
• No deduction shall be made for openings less than 0.5 sq m in area, and no addition shall be made reveals, jambs, soffits, sills, etc. of these openings.
• No deduction shall be made for ends of joists, steps, etc. not exceeding 0.5 sq m in area.
• For openings exceeding 0.5 sq m but not exceeding 3 sq m and when both faces are plastered with the same type of plaster each deduction shall be made for one face only, and the other face shall be allowed for jambs, soffits, and sills which shall not be measured.
• For openings exceeding 0.5 sq m but not exceeding 3 sq m and when two faces are plastered with a different type of plaster or with one side plaster and other side pointed, deduction shall be made on one side of chaukhat (frame)of the door an window on which the width of jambs and reveals is less than the other side, and no deduction shall be made for other side.
• In the case of openings of the area above 3 sq m, each deduction shall be made for both faces of openings, and the jambs and sills shall be measured and added. In taking a measurement of jamb, soffits, and sills, chaukhat (if any) shall not be deducted.
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