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Things Site Engineers Must Know About Reinforcement and Steel Bars

As Per Indian Guidelines Only.

Clear cover to main reinforcement in
Footings : 50 mm
Raft foundation Top : 50 mm
Raft foundation Bottom/ sides : 75 mm
Strap Beam : 50 mm
Grade Slab : 20 mm
Column : 40 mm (d>12mm) 25 mm (d= 12mm)
Shear Wall : 25 mm
Beams : 25 mm
Slabs : 15 mm or not less than diameter of the bar.
Flat Slab : 20 mm
Staircase : 15 mm
Retaining Wall on Earth : 20/ 25 mm
Water retaining structures : 20 / 30 mm
Sunshade (Chajja) : 25 mm

Hook for stirrups is 9D for one side

No. of stirrups = (clear span/Spanning) + 1

For Cantilever anchorage length for main steel is 69D

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“L” for column main rod in footing is minimum of 300mm

Chairs of minimum 12 mm diameter bars should be used.

Minimum diameter of dowel bars should be 12 mm

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

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

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

Minimum number of bars for a square column are 4 and for circular column are 6.

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

Weight of rod per meter length = d2/162 where d is the diameter in mm

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

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.

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In case of spacing of bars
Provide the diameter of the bar, if the diameter of the bar are equal.
Provide the diameter of the larger bar, if the diameter are unequal.
5mm more than the nominal maximum size of the coarse aggregate.

Things Site Engineers Must Know

Check out the Unit Weights and Conversion which will be required on construction site here

We at engineeringcivil.com are thankful to Er Vikrant for submitting this construction site check list which is of great use to all civil engineers.

Things Site Engineers Must Know

Minimum thickness of slab is 125 mm.

Water absorption should not be more than 15 %.

Dimension tolerance for cubes + – 2 mm.

Compressive strength of Bricks is 3.5 N /mm2

Maximum Free fall of concrete allowed is 1.50 m.

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In soil filling as per IS code for every 100 sqm 3 sample for core cutting test should be taken.

Electrical conduits shall not run in column

Earth work excavation for basement above 3 m should be stepped form

Any back filling shall be compacted 95% of dry density at the optimum moisture content and in layers not more than 200mm for filling above structure and 300 mm for no structure

F soling is specified the soling stones shall be laid at 45° to 60° inclination (and not vertical) with interstices filled with sand or moorum.

A set of cube tests shall be carried out for each 30 cum of concrete / each levels of casting / each batch of cement.

Water cement ratio for different grades of concrete shall not exceed 0.45 for M20 and above and 0.50 For M10 / M15 contractor

For concrete grades M20 and above approved admixture shall be used as per mix design requirements.

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.

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Samples from fresh concrete shall be taken and at least a set of 6 cubes of 150mm shall be prepared and
cured. 3 Cubes each at 7 days and 28 days shall be tested for compressive strength. The test results
should be submitted to engineer for approval. If results are unsatisfactory necessary action/rectification/remedial measures has to be exercised.

Water used for both mixing and curing shall be clean and free from injurious amounts of oils, acids, alkalies, salts, sugar and organic materials or other substances that may be deleterious to concrete or steel. The ph shall be generally between 6 and 8.

Cement shall be tested for its setting.
1. The initial setting time shall not be less than 30 minutes.
2. The final setting time shall not be more than 10 hours.

Slump 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)

Curing Days Required
Super Sulphate cement : 7 days
Ordinary Portland cement OPC : 10 days
Minerals and Admixture added cement : 14 days

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Cube Samples
1 – 5 M3 : 1 No.
6 – 15 M3 : 2 No’s
16 – 30 M3 : 3 No’s
31 – 50 M3 : 4 No’s
Above 50 M3 : 4 + 1 No of addition sample for each 50 M3.

Things Site Engineers Must Know About Reinforcement and Steel Bars

Check out the Unit Weights and Conversion which will be required on construction site here

We at engineeringcivil.com are thankful to Er Vikrant for submitting this construction site check list which is of great use to all civil engineers.

What are the Tolerance Limits on Construction Site?

Accuracy of measuring equipment in batching plant.
Cement : + – 2%
Aggregate : + – 3%
Admixture : + – 3%
Water : + – 3%
Mixing time : 2 minutes for one mixing. (Mixing which is being done on site)

Tolerance in Form work
In C/S for columns & Beams deviation is = + 12mm more (or) – 6mm less in size
In footing plan = + 50 mm more (or) – 12 mm less size
In depth = + – 0.05 D (specified thickness).

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Tolerance in Reinforcement
For effective depth D < = 200mm = +- 10mm For effective depth D > 200mm = +- 15mm
For Cover to reinforcement = + 10mm
Maximum freefall of concrete = 1.50 m height.

Tolerance on diameter in length
0-25mm = +- 0.5 %
25-35mm = +- 0.6 %
35-50mm = +- 0.8 %

Tolerance on weight per metre
0-10mm = +- 7%
10-16mm = +- 5%
16 and above = +- 3%

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Tolerance for cutting Length
A) When the specified length is not given = + 75mm (or) – 25 mm
B) When the minimum length is specified = + 50 mm (or) – 0 mm

We are thankful to Er. Vikrant for submitting this to us.

Various Types Of Cranes

A crane is a tower or derrick that is equipped with cables and pulleys that are used to lift and lower material. They are commonly used in the construction industry and in the manufacturing of heavy equipment. Cranes for construction are normally temporary
structures, either fixed to the ground or mounted on a purpose built vehicle.

They can either be controlled from an operator in a cab that travels along with the crane, by a push button pendant control station, or by radio type controls. The crane operator is ultimately responsible for the safety of the crews and the crane.

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Compact Excavator

The compact hydraulic excavator can be a tracked or wheeled vehicle with an approximate operating weight of 13,300 pounds.Normally, it includes a standard backfill blade and features an independent boom swing. The compact hydraulic excavator is also known as a mini excavator.

A compact hydraulic excavator is different from other types of heavy machinery in the sense that all movement and functions of the machine are accomplished through the transfer of hydraulic fluid.The work group and blade are activated by hydraulic fluid acting upon hydraulic cylinders.The rotation and travel functions are also activated by hydraulic fluid powering hydraulic motors.

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