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fathima
fathima

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Beginner

What is the different between smooth form work and rough form work?

  1. AdityaBhandakkar

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    What is the different between smooth form work and rough form work?

    In simple words, smooth formwork makes the surface of wall smooth, while the rough formwork leaves the concrete surface as roughly cast. refer ACI 301- 96 for details about homework and their types. In general, after removing the formwork the surface needs to be smoothed with the help of plasteringRead more

    In simple words, smooth formwork makes the surface of wall smooth, while the rough formwork leaves the concrete surface as roughly cast.

    refer ACI 301- 96 for details about homework and their types.

    In general, after removing the formwork the surface needs to be smoothed with the help of plastering or sandblasting. If the thickness is exceeded 10 mm then it is a type of rough formwork.

    Hope you understood the concept.

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Wellcaffolding
Wellcaffolding

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Which are the materials used for making scaffolding? and which one is better?

  1. aviratdhodare

    aviratdhodare

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    aviratdhodare

    Plywood with wooden Doca H beams. Steel plates Aluform which uses aluminium frames and various nut assemblies For underground works, PECAFORM. For various assemblies like U Jack, tie rod, tie nuts, scaffoldings, stair tower aluminium and steel is used depending on requirement. Where strength is mainRead more

    1. Plywood with wooden Doca H beams.
    2. Steel plates
    3. Aluform which uses aluminium frames and various nut assemblies
    4. For underground works, PECAFORM.
    5. For various assemblies like U Jack, tie rod, tie nuts, scaffoldings, stair tower aluminium and steel is used depending on requirement. Where strength is main priority steel is used and in case of lightweight assembly like scaffoldings for work platforms, aluminium can be used.

    Generally,

    1. Wooden Planks And Plates.
    2. Playboards
    3. Steel Sheets, Make sure it is mild
    4. GI or corrugated sheets
    5. Require Scaffolding of wooden ballies
    6. Scaffolding of Metal Frames
    7. Scaffolding of Bamboos
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fathima
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Why is Traverse Surveying used in Road Projects?

  1. nikeetasharma

    nikeetasharma

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    Traverse surveying is a method to establish control networks. Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point. There are two types of traverse surveying , they are: 1. Closed traverRead more

    Traverse surveying is a method to establish control networks. Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point.

    There are two types of traverse surveying , they are:

    1. Closed traverse: When the lines form a circuit that ends at the starting point, it is known as a closed traverse.

    2. Open traverse: When the lines form a circuit ends elsewhere except the starting point, it is said to be an open traverse.

    So, for the construction of road projects open traverse is used because in this we can extend roads for infinite distances.

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Komal Bhandakkar
Komal Bhandakkar

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What is the substitute material of ballast at railway track?

  1. nikeetasharma

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    Ballast also holds the track in place as the trains roll over. It is typically consists of crushed stone, although other less suitable, materials have sometimes been used such as burnt clay.

    Ballast also holds the track in place as the trains roll over. It is typically consists of crushed stone, although other less suitable, materials have sometimes been used such as burnt clay.

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Shivan
Shivan

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What are the different types of compactors?

  1. aviratdhodare

    aviratdhodare

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    aviratdhodare

    Types of compactors Smooth wheeled rollers: Generally and imp used for compaction of any type of roads compaction. Sheepsfoot Rollers: Also called as tamping roller, consists of rectangle boots on the roller drum in hexagon pattern. Pneumatic Roller: Also called rubber tyre roller. Vibratory roller:Read more

    Types of compactors

    1. Smooth wheeled rollers: Generally and imp used for compaction of any type of roads compaction.
    2. Sheepsfoot Rollers: Also called as tamping roller, consists of rectangle boots on the roller drum in hexagon pattern.
    3. Pneumatic Roller: Also called rubber tyre roller.
    4. Vibratory roller: Rollers with vibration, for better compaction.
    5. Rammers: For small places with impact load, hand or machine operated coz of light wt.
    6. Vibratory Plate Compactor: For very small & conjusted place
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Himanshu joshi
Himanshu joshi

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What is key differences between cable stayed and cable suspension bridge?

  1. nikeetasharma

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    Cable stayed bridges may look similar to suspension bridges. They both have roadways that hang from cables and both have towers. But the two bridges support the load of the roadways in very different ways. The difference lies in how the cables are connected to the towers . In suspension bridges, theRead more

    Cable stayed bridges may look similar to suspension bridges. They both have roadways that hang from cables and both have towers. But the two bridges support the load of the roadways in very different ways. The difference lies in how the cables are connected to the towers . In suspension bridges, the cable ride freely across the towers, transmitting the load to the anchorages at either end. In cable stayed bridges, the cables are attached to the towers, which alone bear the load.

    The cable can be attached to the roadway in a variety of ways. In a radial pattern cables extend from several points on the road to a single point at the top of the tower. In a parallel pattern, cables are attached at different heights along tower running parallel to one another.

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Tips_and_tricks
Tips_and_tricks

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What are the Types of members in Prestressed Structures?

  1. nikeetasharma

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    Pre-stressed concrete is a form of concrete used in construction. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service. According to the construction methods there are two kinds of prestressed concrete :- - Pre-tenRead more

    Pre-stressed concrete is a form of concrete used in construction. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service. According to the construction methods there are two kinds of prestressed concrete :-
    – Pre-tensioned concrete
    – Bonded Post-tensioned concrete
    – Unbonded Post-tensioned concrete

    The three types of members in prestressed concrete are as follows:-

    1. Neither allowing tension nor crack.
    2. Allowing tension within permissible stress but cracking is not allowed.
    3. Tension and crack both are allowed but within permissible stress.

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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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