Civil Engineers do many activities at the construction sites and there is certain work which repetitive in the future. So, some points and tricks and tips which civil engineers should remember for faster calculation as well as quick solutions to construction site problems.
Points to Remember For Civil Site Engineers
Few general points to remember for civil site engineers to make the construction work easier while maintaining the quality of construction are given below.
BIS abbreviation Bureau of Indian Standard.
ASTM abbreviation American Society for Testing Material.
C/C means Center to Center distance.
DL means Development length
The minimum thickness of the slab is 125mm.
Water absorption of bricks should not exceed 15%.
Dimension tolerance for cubes +/– 2 mm.
Lapping is not allowed for the bar having diameters more than 36mm.
Chair spacing maximum is 1.00m or 1 no per 1 m2.
For dowels bar minimum of 12mm diameter should be used.
Chairs a minimum of 12mm diameter bars to be used.
Longitudinal reinforcement not less than 0.8% and more than 6% of the gross cross-section.
The minimum bars for the square column is 4 no’s and 6 no’s for the circular column.
The main bar in the slab shall not be less than 8mm (HYDS) or 10mm (Plain bars) and the distribution bar not less than 8mm and not more than 1/8 of slab thickness.
The freefall of concrete is allowed a maximum to 1.5m.
Lap slices not be used for bar larger than 36mm diameter.
Water PH values less than 6 should not be used for construction purposes.
The compressive strength of brick is 3.5 N/mm2.
In steel reinforcement biding wire is required 8 kg per MT.
Electrical conduits should not run in the column.
In soil filling as per IS code for every 100 sq.m, 3 samples for core cutting tests should be taken.
The initial setting time of cement shall not be less than 30 minutes and the final setting time of cement are 600 minutes.
DPC means the Damp Proof Course.
The thickness of DPC should not be less than 2.5cm.
The height of the floor is usually 3m or 10ft.
The weight of the bar is calculated using formula D2/162 (where D is the diameter of the bar).
The no’s of bricks required for 1m3 of brick masonry is 550 bricks.
Standard size of brick is 19cm x 9cm x 4cm.
The slope or pitch of the stair should be between 25 degrees to 40 degrees.
The rise in stair is in between 150mm to 200mm.
The tread in the staircase is in between 250mm to 300mm.
Hook length should be a minimum of 9D. (where D is the diameter of the bar)
The volume of 50kg cement is 1.25ft3.
TMT bars: TMT means Thermo Mechanically Treated Bars
Cement more than 3 months old cannot be used for construction work.
The length of each bar from the factory is 12m.
Cube Samples Required for Different Quantity of Concrete
1-5 m3
1 Sample
6-15 m3
2 Samples
16-30 m3
3 Samples
31-50 m3
4 Samples
51 m3 and above
4 Samples + 1 Sample addition of each 50 m3
De-Shuttering Time of Different RCC Member
RCC Member
De-Shuttering Time
For Columns, vertical formworks
16-24 hrs
Soffit form work to slab
3 days (props to be refixed after removal)
Soffit to beam props
7 days (props to refixed after removal)
Beam spanning upto 4.5m
7 days
Beam spanning over 4.5m
14 days
Arches spanning 4.5m
14 days
Arches spanning over 4.5m
21 days
Density of Materials
Material
Density
Bricks
1600 Kg/m3-1920 Kg/m3
Cement
1440 Kg/m3
Sand
1100 Kg/m3-1600 Kg/m3
Steel
7850 Kg/m3
Water
1000 Kg/m3
R.C.C
2310 Kg/m3-2700 Kg/m3
P.C.C
2400 Kg/m3
Concrete Mix Ratio of Different Grades of Concrete
Concrete Grade
Mix Ratio
M5
1:5:10
M7.5
1:4:8
M10
1:3:6
M15
1:2:4
M20
1:1.5:3
M25
1:1:2
M30 and Above
Mix Design Require
Concrete Cover or Clear Cover to Reinforcement Bar
