Points That Site Engineer Should Remember

Following are few general points to remember for civil site engineers to make the construction work easier while maintaining quality of construction.

·         Lapping is not allowed for the bars having diameters more than 36 mm.

·         Chair spacing maximum spacing is 1.00 m (or) 1 No per 1m².

·         For dowels rod minimum of 12 mm diameter should be used.

·         Chairs minimum of 12 mm diameter bars to be used.

·         Longitudinal reinforcement not less than 0.8% and more than 6% of gross C/S.

·         Minimum bars for square column is 4 No’s and 6 No’s for circular column.

·         Main bars in the slabs shall not be less than 8 mm (HYSD) or 10 mm (Plain bars) and the distributors not less than 8 mm and not more than 1/8 of slab thickness.

·         Minimum thickness of slab is 125 mm.

·         Dimension tolerance for cubes + 2 mm.

·         Free fall of concrete is allowed maximum to 1.50m.

·         Lap slices not be used for bar larger than 36 mm.

·         Water absorption of bricks should not be more than 15 %.

·         PH value of the water should not be less than 6.

·         Compressive strength of Bricks is 3.5 N / mm^2.

·         In steel reinforcement binding wire required is 8 kg per MT.

·         In soil filling as per IS code, 3 samples should be taken for core cutting test for every 100m².

Density of Materials:

Material	Density
Bricks	1600 – 1920 kg/m3
Concrete block	1920 kg/ m3
Reinforced concrete	2310 – 2700 kg/ m3

Curing time of RCC Members for different types of cement:

Super Sulphate cement: 7 days

Ordinary Portland cement OPC: 10 days

Minerals & Admixture added cement: 14 days

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 upto 4.5m	7 days
Beams spanning over 4.5m	14 days
Arches spanning up to 6m	14 days
Arches spanning over 6m	21 days

Cube samples required for different quantity of concrete:

Quantity of Concrete	No. of cubes required
1 – 5 m3	1 No’s
6 0 15 m3	2 No’s
16 – 30 m3	3 No’s
31 – 50 m3	4 No’s
Above 50 m3	4 + 1 No’s of addition of each 50 m3