civilbase: IMPORTANT POINTS FOR CIVIL ENGINEERS

IMPORTANT POINTS FOR CIVIL ENGINEERS

· Height of Parapet wall should be 1m

· Thickness of DPC = 2.5cm or 1” inch

· Height of building = 3.15m

· Height of window = 2.1m

· One bag of cement = 1.25cubic feet or 0.0347m³

· Weight of one cement bag = 50kg

· Minimum thickness of slab = 125mm

· No. of cement bags in 1m³ = 28.8 bags

· Lintel thickness = 15cm

· Lintel is provided at 2.4m in case of a brick wall

· Minimum the diameter of bass used in slap = 8mm

· Minimum the diameter of bass used in column = 12mm

· Minimum the diameter of bass in dowel bass = 12mm

· Maximum ø bass in slab = ⅛×thickness of the slab

· Maximum chair spacing = 1m

· Dimensional tolerance of cube = ±2mm

· Maximum water absorption of first-class brick = 15% if its day wt

· Initial setting time of cement = 30minutes

· Final setting time = 10hours(600minutes)

{OPC}

Ordinary Portland Cement

· DPR = Detailed Project Report

· Unit weight

1. RCC = 25 KN/m3 = 25000 N/m³

2. PCC = 24 KN/m3 = 24000 N/m³

3. Steel = 7850 kg/m³

· 1 Gallon = 3.78 litres

· Minimum No. of bass

1. For square column or rectangular = 4bass

2. For circular column = 6bass

· Standard sand in India is obtained from Ennore, TamilNadu

· 1 Yard = 3 feet

· Weight of steel = D² / 162.2 kg/m

Weight of steel = D² / 533 kg/ft

· Slope od staircase = 25^o - 40^o

· Size of concrete testing cube = 150_mm×150_mm×150_mm

· Concrete cube is filled in 3 layers

· Slump the cone is filled in 4 layers

· Cement should be used within three months of manufacturing

· Minimum the thickness of shear wall = 150mm

Maximum thickness if shear wall = 400mm

· Universal the testing machine is used for compression test of concrete & tensile test of steel reinforcement

· Minimum curing period

1. 7days → Normal weather condition

2. 10days → Dry & Hot weather condition

· Minimum percentage of steel in column = 0.8% of Gross area

Maximum percentage of steel in column = 6% of Gross area

· Nominal cover

1. Footing = 50mm

2. Column = 40mm

3. Slab = 20mm

4. Beam = 25mm

· Least count:

1. Compass = 30’ (30 minutes)

2. Dumpy level = 5mm

3. Auto level = 5mm

4. Theodolite = 20” (20 seconds)

· Air voids left in concrete is called as HONEY COMBING

· The transverse reinforcement of column is called TIES

· The transverse reinforcement in beams are called STRIPPERS

· TMT → Thermomechanically treated Bars

TMX → Thermax powered Bars

SD → Super ductile Bars

HYSD → High Yield strength Deformed bars

CTD → Cold twisted deformed bars

· Angle of staircase = 25^o – 40^o

· Riser = 150mm – 200mm

Tread = 250mm – 300mm

· Minimum hook length = 9D

· Standard size of Brick = 19×9×9mm

· Modular size of Brick = 20×10×10mm

· No. of bricks in 1m³ = 500 bricks

· No. of bricks in 230mm brick wall in 1cubic meter = 496 bricks (including wastage)

· No. of bricks in 115mm thick wall for 1sq.m = 56

Bricks

· 8 – 12kg of binding wire is used per metric tonne of steel 1000kg = 8kg 12kg

· Cement ingredients are burnt at 1400^oC temperature

· 1BHK stands for

1Bedroom, 1Hall, 1Kitchen

· Short columns fail in Crushing

· Long columns fail in Buckling

· Intermediate columns can fail in both Buckling and Crushing

· Cement: Sand: Aggregate ratio for different grades of concrete

C:S: A

M_7.51:4: 8

M₁₀ 1:3: 6

M₁₅ 1:2: 4

M₂₀ 1: 1.5: 3

M₂₅ 1:1: 2

· Segregation is Separation of cement Sand and Aggregate w/c=0.4

1. This is caused due to improper water-cement ratio w/c=

2. It is also caused when concrete is poured above 1.5m high

· Bleeding: when water comes out of freshly made concrete it is called as Bleeding of Concrete

· Retarder is an admixture added to concrete which keeps concretely workable for longer time. It increases the setting time of concrete

Eg: Sugar is a retarder {accelerates calc₂}

Gypsum

· Deflection means temporary displacement

· Deformation is permanent displacement

· The the ratio of the weight of water to the weight of cement in concrete is called as water cement ratio

w/c = Weight of water = 0.4

Weight of cement

w/c = 0.4

w/c = 0.35

· 1 Ordinary Portland cement → General construction

2 Pow heat cement → Damns

Abutments

Retaining walls

3 Sulphate Resisting Cement → Marine Structures prone to Sulphate attack

· Grades of OPC

Compressive strength (N/mm₂)

Grades	3 days	7 days	28 days
33 N/mm	16 N/mm²	22	33 N/mm²
43 N/mm	23	33	43 N/mm²
53 N/mm	27	37	53 N/mm²

Tensile strength of concrete = 0.7 √fck

Flexural strength fck = 20 N/mm² M₂₀

· Modulus od elasticity of concrete

Ec = 5000√fck

· Characteristics strength

Strength below which not more than 5% of test results are expected to fail

100 cubes

M₃₅

Ordinary concrete M₁₀ ^M15M₂₀

Standard concrete M₂₅ ^M20 M₅₅

High strength concrete M₆₀ M₈₀

· RCC (M₂₀)

· In mixer machine concrete should be mixed for 2 – 3 minutes

· Storage of Cement

1. Cement should be stored in dry places

2. 200mm away from the floor (in a platform)

3. 300mm away from walls

4. Not more than 10 bags stacked

5. Away from moisture & chemicals

· Water absorption for bricks 1^st class should be <20%

· Water absorption should be <5% for the building stones

· F.O.S for steel = 1.15

· F.O.S for concrete = 1.5

· Youngs modulus of steel Es = 2×10⁵ N/mm²

· Types of steel

1. Mild steel

Fe 250

250 N/mm² is characteristic strength

Fy = 250 N/mm²

· HYSD → High Yield Strength Deformed bass

ü Fe 415 Fy = 415 N/mm²

ü Fe 500 Fy = 500 N/mm²

Er.SP.ASWINPALANIAPPAN., M.E.,(Strut/.,)

Structural Engineer

civilbase

Monday, 11 May 2020

IMPORTANT POINTS FOR CIVIL ENGINEERS

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