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vivek gami
vivek gami

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What is Pickup Weir Structure? Why its call pickup? Where it is use?

  1. nikeetasharma

    nikeetasharma

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    Weirs are fixed barriers across a river or stream that force water to flow over their tops, where the height of the water above the weir can be used to calculate flow.

    Weirs are fixed barriers across a river or stream that force water to flow over their tops, where the height of the water above the weir can be used to calculate flow.

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Komal Bhandakkar
Komal Bhandakkar

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Difference between OPC 53 &OPC 43 grade of cement according to the initial and final setting time of cement.

  1. nikeetasharma

    nikeetasharma

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    OPC 43 :- The 43 grade OPC is the most popular general-purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country. This OPC43 continues to gain strength after 28 days. OPC 53 :- The 53 grade OPC is higher strength cement to meetRead more

    OPC 43 :- The 43 grade OPC is the most popular general-purpose cement in the country today. The production of 43 grade OPC is nearly 50% of the total production of cement in the country. This OPC43 continues to gain strength after 28 days.

    OPC 53 :- The 53 grade OPC is higher strength cement to meet the needs of the consumer for higher strength concrete. As per BIS requirements the minimum 28 days compressive strength of 53 grade OPC should not be less than 53 Mpa. Therefore, there is a vast difference in setting time of these cements. It sets very quicker and has low initial setting time. These types of cement can be used where rapid hardening is not needed.

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Komal Bhandakkar
Komal Bhandakkar

Komal Bhandakkar

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What is the range of density of Carbon Fibre in Conductive Concrete?

  1. Komal Bhandakkar

    Komal Bhandakkar

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    Komal Bhandakkar AUTHOR
    What is the range of density of Carbon Fibre in Conductive Concrete?

    Conductive carbon fiber reinforced concrete is a self-heating material specially used for prevention against ice formation. Following are the specification of Carbon fibre used in conductive concrete; Density-1.81 g/cm 3 Diameter- 7.2 micron Carbon Content-95% Tensile Strength-3800MPa Elastic ModuluRead more

    Conductive carbon fiber reinforced concrete is a self-heating material specially used for prevention against ice formation.

    Following are the specification of Carbon fibre used in conductive concrete;

    1. Density-1.81 g/cm 3
    2. Diameter- 7.2 micron
    3. Carbon Content-95%
    4. Tensile Strength-3800MPa
    5. Elastic Modulus-242GPa
    6. Resistivity-1.52 x 10^3
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Asked: In:
Komal Bhandakkar
Komal Bhandakkar

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What is Golden Ratio? How can we find out the Golden Ratio of any rectangular shaped body?

  1. aviratdhodare

    aviratdhodare

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    aviratdhodare

    The Golden Ratio is an irrational number with never-ending infinite numbers of digits, 1.618033988749895..., which are highly confusing and misleading. It is a linear number and represents only two dimensions of the object. Drawing It Here is one way to draw a rectangle with the Golden Ratio: Draw aRead more

    The Golden Ratio is an irrational number with never-ending infinite numbers of digits, 1.618033988749895…, which are highly confusing and misleading. It is a linear number and represents only two dimensions of the object.

    Drawing It

    Here is one way to draw a rectangle with the Golden Ratio:

    • Draw a square (of size “1”)
    • Place a dot half way along one side
    • Draw a line from that point to an opposite corner (it will be √5/2 in length)
    • Turn that line so that it runs along the square’s side

    Then you can extend the square to be a rectangle with the Golden Ratio.

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Gopal Mishra
Gopal Mishra

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Can you tell me types of slabs? And how can we design them?

  1. aviratdhodare

    aviratdhodare

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    aviratdhodare

    Flat slab - Flat slab is minimum 8″ or 0.2m. Slab without drop and column without column head(capital). Slab with drop and column without column head. Slab without drop and column with column head. Slab with drop and column with column head. Conventional slab - conventional slab is 4″ or 10cm. 5″ toRead more

    Flat slab – Flat slab is minimum 8″ or 0.2m.

    1. Slab without drop and column without column head(capital).
    2. Slab with drop and column without column head.
    3. Slab without drop and column with column head.
    4. Slab with drop and column with column head.


    Conventional slab – conventional slab is 4″ or 10cm. 5″ to 6″ inches

    1. One-Way Slab
    2. Two-Way Slab

    Hollow core ribbed slab

    hollow core ribbed slab

    Hardy slab

    1. One way Hardy Slab
    2. Two way Hardy slab

    Waffle slab

    1. Triangular pod system
    2. Square pod system

    Dome slab

    dome slab

    Pitch roof slab

    Pitch roof slab

    Slab with arches

    arch slab

    Post tension slab

    post tension slab

    Pre tension Slab

    Low roof slab

    Projected slab

    projected slab

    Grads Slab/ Slab on grade

    slab with sand and concreteconcrete slab

    Sunken Slab

    sunken slab below ground level

     

    a) Effective span of slab:

    Effective span of slab shall be lesser of the two

    1. L = clear span + d (effective depth )

    2. L = Center to center distance between the support

    b) Depth of slab:

    The depth of slab depends on bending moment and deflection criterion. the trail depth can be obtained using:

    • Effective depth d= Span /((L/d)Basic x modification factor)
    • For obtaining modification factor, the percentage of steel for slab can be assumed from 0.2 to 0.5%.
    • The effective depth d of two way slabs can also be assumed using cl.24.1,IS 456 provided short span is 3.5m and loading class is <3.5KN/m2

    Type of support

    Simply supported

    Fe-250 – L/35

    Fe-415 – L/28

    Continuous support

    Fe-250 – L/40

    Fe-415 – L/32

    Or, the following thumb rules can be used:

    • One way slab d=(L/22) to (L/28).
    • Two way simply supported slab d=(L/20) to (L/30)
    • Two way restrained slab d=(L/30) to (L/32)

    c) Load on slab:

    The load on slab comprises of Dead load, floor finish and live load. The loads are calculated per unit area (load/m2).

    Dead load = D x 25 kN/m2 ( Where D is thickness of slab in m)

    Floor finish (Assumed as)= 1 to 2 kN/m2

    Live load (Assumed as) = 3 to 5 kN/m2 (depending on the occupancy of the building)

    Detailing Requirements of RCC Slab as per IS456: 2000

    a) Nominal Cover:

    For Mild exposure – 20 mm

    For Moderate exposure – 30 mm

    However, if the diameter of bar do not exceed 12 mm, or cover may be reduced by 5 mm. Thus for main reinforcement up to 12 mm diameter bar and for mild exposure, the nominal cover is 15 mm.

    b) Minimum reinforcement: The reinforcement in either direction in slab shall not be less than

    • 0.15% of the total cross sectional area for Fe-250 steel
    • 0.12% of the total cross-sectional area for Fe-415 & Fe-500 steel.

    c) Spacing of bars: The maximum spacing of bars shall not exceed

    • Main Steel – 3d or 300 mm whichever is smaller
    • Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any value.

    d) Maximum diameter of bar: The maximum diameter of bar in slab, shall not exceed D/8, where D is the total thickness of slab.

     

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Asked: In:
Jigar Chaudhari
Jigar Chaudhari

Jigar Chaudhari

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Why gravity dam is called a gravity dam? Is there any reason behind the name?  

  1. Kuldeep Singh

    Kuldeep Singh

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    Kuldeep Singh Learner

    Gravity dam, as the name suggests, is a dam that resists the water upstream by the use of its weight itself, unlike earthen dams and embankment dams that employ the shear strength of the soil. The dam is designed so that the resultant of the water pressure, earth pressure, and all other forces are aRead more

    Gravity dam, as the name suggests, is a dam that resists the water upstream by the use of its weight itself, unlike earthen dams and embankment dams that employ the shear strength of the soil.

    The dam is designed so that the resultant of the water pressure, earth pressure, and all other forces are aligned and balanced by the weight of the dam itself.

    They are generally made of Roller compacted concrete.

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Komal Bhandakkar
Komal Bhandakkar

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Why the colour of a civil engineer’s cap is only white? What is the purpose of it?

  1. aviratdhodare

    aviratdhodare

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    aviratdhodare

    It turns out that colors like yellow and red are common indicative colours that appear in nature, and humans, along with many predators have evolved to easily spot such colorations. However yellow is a bright and noticeable colour that doesn't usually appear elsewhere in our modern world, so is easiRead more

    It turns out that colors like yellow and red are common indicative colours that appear in nature, and humans, along with many predators have evolved to easily spot such colorations.

    However yellow is a bright and noticeable colour that doesn’t usually appear elsewhere in our modern world, so is easily noticed.

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Asked: In:
nikeetasharma
nikeetasharma

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Guru

how to calculate twisting moment?

  1. nikeetasharma

    nikeetasharma

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    nikeetasharma Guru

    Torsion is the twisting of a beam under the action of a torque (twisting moment). It is systematically applied to screws, nuts, axles, drive shafts etc, and is also generated more randomly under service conditions in car bodies, boat hulls, aircraft fuselages, bridges, springs and many other structuRead more

    Torsion is the twisting of a beam under the action of a torque (twisting moment). It is systematically applied to screws, nuts, axles, drive shafts etc, and is also generated more randomly under service conditions in car bodies, boat hulls, aircraft fuselages, bridges, springs and many other structures and components. A torque, T , has the same units (N m) as a bending moment, M . Both are the product of a force and a distance. In the case of a torque, the force is tangential and the distance is the radial distance between this tangent and the axis of rotation.

    All torsion problems can be solved using the following formula:

    T/J = shear stress/ r = (G * angle)/ L

    where:

    T = torque or twisting moment, [N×m, lb×in]
    J = polar moment of inertia or polar second moment of area about shaft axis, [m4, in4]
    τ = shear stress at outer fibre, [Pa, psi]
    r = radius of the shaft, [m, in]
    G = modulus of rigidity (PanGlobal and Reed’s) or shear modulus (everybody else), [Pa, psi]
    θ = angle of twist, [rad]
    L = length of the shaft, [m, in]

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