Construction Steps of a Highway Underpass in UAE

Construction Steps of a Highway Underpass in UAE

This is the commentary of a video which shows the construction steps of an underpass. To watch the video, please click the below link

https://youtu.be/DosoflT2k4k

An underpass is a tunnel containing a road or pedestrian passageway running underneath a road or railway 

Formation works

• Coordinates and levels are marked by the surveyor where underpass is to be constructed.
• According to that the soil is excavated for foundation works.
• Soil is excavated 30cm from blinding top level given by the surveyor.
• After excavation, water is sprayed and compaction is done for more strength.
• The strong soil called road base is spread above that in layers.
• Each layers is spread and compacted well.
• Strings are connected between the levels given by surveyor.
• Road base is made 10cm below from this level.
• Now our formation is ready for blinding.

Plate load test

•  Plate Load test is conducted and ultimate bearing capacity of soil is calculated.
• After the passing of test, Foundation works starts.

Blinding

• Blinding is the Base for Base slab.
• Form work of blinding is done.
• Points are checked and levels are marked by the surveyor.
• Polythene sheets are placed on the ground for preventing leakage of concrete slurry.

Concreting

• We are doing concrete using Concrete pumps.
• The concrete pump is set in Suitable position.
•  Now concrete for pouring comes in an RMC vehicle.
•  Concrete Sample is taken from the vehicle for Compaction test and Slump tests.
•  If the slump result is positive, then we start pouring concrete to input box of pump.
• Water the place before concrete.
•  Now Pump pour concrete to the required location.
•  The pouring is controlled by the operator with a remote according to the requirement.
• Tamping and Spreading is done by using Punchas and small shovels.
•  Finishing is done using Bull floats and trowels.
• After setting, Hessian cloths and polythene sheets are used for curing.

Waterproofing

• A primer called polyprime SB is applied for waterproofing
• After drying of primer, a water proofing membrane called Bitustick is applied on it.
• Suitable overlaps are given for good waterproofing.
• Water proofing here is done to prevent the entry of water from below to the structure

Screed

• Then screed concrete is provided above this waterproof membrane for its protection.
• Screed  thickness is 5cm
• Shuttering and concreting is done similar to the blinding.
• After its curing, we starts Base Slab works.

Base slab

Steel works

• The Steel work is done above the screed according to the drawing.
• Cranes are used for the shifting of steel Bundles.
• Bottom steels, Chairs, Face bars, Top steels are placed and tied firmly using the binding wires.
• Starter bars for the upcoming walls are also provided for the connection.
• Cleaning is done before form work fixing.

Form works

• Meanwhile the Form works can be fabricated.
• Form work is fabricated using soldiers, GTX or H20 beams, and Plywood.
• It is cleaned and rebool oil is applied in it for easy removal.
• Coordinates of base slab is given by the surveyor on the ground.
• After steel inspection, form works are placed on that points.
• Strong supports are given to the ground. 
• The is water stop fixed between construction joints of base slab and wall for prevention of water entering.
• Coordinates are checked and the form work is adjusted to the required point.
• The Levels of concrete are marked.
• Kicker shutter is also made for the support of upcoming walls in the dimension of wall.
• Formworks and its supports are inspected thoroughly.
• Covers of steel are checked.
• Level pipes are fixed for leveling.
• Now its ready for concrete.

Concrete

• Materials for concrete such as Generators, water, converters, vibrator needles, leveling machines etc. are arranged.
• Pump is set.  Water is sprayed.
• During the Concrete pour, Mechanical vibrators are applied thoroughly.
• Concrete is placed layer by layer up to top.
• When it reaches top, leveling machine is operated and the concrete is leveled.
• Level pipes are removed.
• Then finishing is done using Bull floats.
• So base slab concrete is done.
• Curing is done. Hessian cloth and polythene sheet is used for efficient curing.

ü  Up to now we have seen the construction of blinding, waterproofing above that, screed and base slab. Now we are going to do the RCC walls

RCC walls

• In the construction joints between base slab and walls, scabbling is done

Scaffolding

• For the steelworks access scaffolding is to be made.
• Access scaffolding is made using cup-lock scaffolding materials.
• Now its ready for steel works

Steel works

• Steels are fixed according to the drawings.
• Crane is used for easiness of works.
• Main bars, face bars etc. are fixed and tied using binding wires.
• Cover blocks are fixed for suitable covers.

Form works

• Wall Form work is fabricated using soldiers, GTX or H20 beams and plywoods.
•  Form works are made according to drawing size.
• They are cleaned and rebool oil is applied.
•  Form works are lifted using crane and fixed in correct position in touch with kicker below.
• Support is given using soldier props, push pull props etc. it is connected to concrete blocks or drilled to base slab.
• Connections are made between different Form works. Formtape is applied in joints.
• Tie rods are connects between shutters on both sides.
• Form works are aligned according to surveyor coordinates by adjusting the supports.
• Verticality is checked using the plumb bob.
• Level is also marked.
• The Form works and supports are to be thoroughly inspected and is made strong so that it can withstand the upcoming concrete.

Concrete

• Concrete setups are arranged.
• The concrete pump is set. Concrete came in the RMC vehicle.
• Concrete is placed layer by layer upto top
• Effective compaction is done at each layer.
• Curing is done at the top using hessian cloth and polythene sheets.

Deshuttering

•  Deshuttering done after Hardening of concrete.
• Wet Hessian cloths with Polythene sheets are used for curing.
• Scaffolding are also removed.
• Like this the other RCC walls is also constructed.

Send your Opinions and Suggesions to my Email Id

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Remaining Steps will be updated in the next video.

Thank You.

Construction steps of a House in India- 2

Construction steps of a House in India- 2

(This is the Commentary of video that we had updated in YouTube

Watch "Construction Steps of a House in India 2" on YouTube

https://youtu.be/XaHpTvUfnfQ

)

Ø  In the previous video, we have seen the construction up to the plinth beam level.

Ø  Hi friends, in this video we are going to watch the construction of superstructure above the plinth beam.

COLUMNS

Ø  This is the drawing of our column. It is (35×21) cm² column,with 6 number of 12 mm dia bars, with stirrups.

Ø  We had laid steels, for the upcoming columns from below.

Ø  They are raised according to the height of column

Ø  In the case, were lintel is constructing after the column, we have to provide extra steels at lintel level, for connecting with lintel.

Ø  For this, 2 steels are fixed on each side and is folded by a paper piece on the end for its easy identification after deshuttering.

Ø  Now steel framework of column is ready.

Ø  Setting out is done and the outer line of the columns,are marked in the cement sand paste.

Ø  A small shoe also called starter is made there for proper arrangement of column shutter

Ø  On the next day, shutter of the shoe is removed and the column shutter is fixed tightly on that shoe.

Ø  Shutter should be vertical.

Ø  For that, an apparatus consists of two woods of equal dimension,and a rope with a weight is used

Ø  When the woods comes parallel, the column shutter is vertical.

Ø  Plumb bob is also used to check verticality.

Ø  It is repeated on four sides.

Ø  When the shutter comes in correct vertical position it is fixed using the supports on 4 sides

Ø  Now it is ready for concreting

Ø  Before concreting,inside formwork is made wet by pouring water.

Ø  Concrete mix is poured and is compacted very well.

Ø  Pouring and compaction, repeats up to the required level.

Ø  After 24 hours, the formwork is removed gently

Ø  This is our column. Like this we built all column structures.

Ø  Curing is to be done from now.

Ø  Curing is to done preferably to 14 days at regular intervals, or at least to 7 days.

Ø  Jute bags are used for the presence of moisture in the surface.

DOOR FRAMES

Ø  Frames of doors, windows and ventilations can be of different materials like wood, concrete, steel etc.

Ø  For wood frames, we applied thermite proof material and wood primer. In steels of windows, metal primer is applied.

Ø  Place of activity is cleaned and made wet

Ø  Mark the position where door frame is coming

Ø  Doorframe is placed

Ø  A rope is laid through the upper hand of the frame to the two sides and is connected to a block

Ø  Now door frame is made vertical using the plumb bob. All sides are checked

Ø  The frame is then fixed in the vertical position by tightening the rope on the block in both sides.

Ø  Other door frames are fixed in the same way.

Ø  For making the top of all door frames in the same level, a levelling apparatus of small hose with water inside is used.

Ø  The ends of the hose is positioned upwards at the top of door frames

Ø  When the 2^nd frame comes in the same water level of 1^st frame, it is fixed in that position

Ø  Hold fasts are fixed to the frames for connection with masonry

Ø  After this masonry works can be done on its sides

MASONRY WORKS

Ø  Masonry can be done by using cement blocks, bricks, laterites etc.

Ø  We are using laterites of size 33cm x 19cm x 21cm.

Ø  Also some bricks to fill gaps

Ø  Rope is laid after setting out

Ø  The place is cleaned and watered

Ø  Cement mortar is applied

Ø  Laterites are placed in the cement mortars with small gaps in between

Ø  Cement mortars is applied on this gaps and is compacted and levelled using the trowels. This are joints

Ø  It is also applied on sides for good bonding

Ø  Plumb bob an levelling staffs are used for levelling

Ø  Above this layer of laterite, cement mortar is applied

Ø  Then next layer of laterites are laid.

Ø  And the steps are repeated

Ø  The cement mortar is prepared by mixing 1 bowl of cement with 6 bowl of sand with adequate water.

Ø  The edges of middle layer is in the centre of lower and upper layer laterite and vice versa

Ø  This is stretcher bond. This pattern will give good bondage.

 WINDOW FRAMES

Ø  After 3 or 4 layers of laterites, we have to think about window frameworks

Ø  If there is any decorations coming below, it is done now.

Ø  Window is placed

Ø  Using two side opened hose with water inside, height is corrected

Ø  Levelled using plumb bob and levelling staff

Ø  It is fixed in that position using a rope tightened on both sides.

Ø  Then laterites are laid on both sides

Ø  If there are alamaras coming inside the wall, their positions are marked and laterites are not laid there.

VENTILLATION

Ø  Ventilations are also fixed in the same manner as that of doors and windows.

Ø  The top level of doors, windows and ventilations are same so that lintel is coming above this level

LINTEL

Ø  Lintel is usually given at a height of about 2.1m

Ø  Formwork of lintel is fixed

Ø  Steel works are prepared

Ø  We used 4 number of 8 mm dia bars interconnected by stirrups

Ø  It is placed on formwork above the cover block

Ø  If there is any window shades or any decorations or berth slabs is coming in this level, it should be considered.

Ø  There formwork and steel works are done and they should be interconnected with lintel

Ø  To make the side slabs of alamaras in future, steels are given from lintel.

Ø  We had provided steels in column at 2.1m level to connect with lintel

Ø  The paper is identified and steels are taken out using the chisel

Ø  They are connected to lintel steel for good bondage

Ø  The gaps between the joints of formworks are close to prevent the leakage of slurry.

Ø  On the day of concrete, water the formwork

Ø  Concrete mix is placed

Ø  It is vibrated or tamped well

Ø  Then levelled using floats and trowels

Ø  Lintel thickness is 15 cm

Ø  Concrete of berth slabs and window shades were done along with this

Ø  They have thickness 10 cm

Ø  Curing is done continuously after it hardens preferably for 14 days or at least to 7 days

Ø  After the removal of side shutter, laterite works can be continued up to the roof level

Ø  At 2.40 m level, we had an extra structure of pergolas and small slabs on the 2^nd floor. They are done

Ø  Height of one floor is 3.06m.

So laterite works are done to this level

Ø  Small spaces are leaved above for the air movements.

STAIR CASE

Ø  This are the drawings of our staircase.

Ø  Some are straight and some are rounds steps with

Rise     = 16.6 cm

Thread = 27.5 cm

 Width = 90 cm

Ø  The positions are marked on the floor or ground according to plan

Ø  Now woods are arranged and shuttering is done according to the shape of the steps

Ø  Suitable supports are given

Ø  For round steps, card boards are used for getting the proper shape.

Ø  8 mm steels are used for its work.

Ø  They are cut suitably and suitable rings are prepared

Ø  It is laid on the formwork above the cover blocks.

Ø  Our stair case starts from 1^st floor, so we had laid steels for that from the slab.

Ø  This steel is connected to the steel of staircase.

Ø  In case if steps are built from ground, a footing is needed for it.

Ø  A square footing of 3 foot side is made usually.

Ø  And the steel is raised from it is connected to the steel of staircase.

Ø  Now it is the time for concrete.

Ø  Formwork is cleaned and is watered,

Ø  Concrete mix is placed

Ø  The metal used for it is ¾ inch or ½ inch or a mix of them, for the concrete mix to go through small gaps of reinforcement.

Ø  It is properly compacted.

Ø  Thus concreting is over.

Ø  Curing is done

Ø  Jute bags are laid for proper curing

Ø  After 21 days we removed the shutter.

RETAINING WALLS

Ø  We have an extra structure called retaining walls or RCC walls

Ø  This is to withstand the load of soil coming on one side of the building

Ø  We used 8 mm and 10 mm dia bars

Ø  Waterproof material is added while concreting.

Ø  Shuttering and concreting is done on two parts on two days.

Ø  Up to now we have constructed foundation, plinth beams, columns, doorframes, masonry, window frames, ventilations and masonry, lintel and masonry above lintel.

Ø  Now we are going for roof slab construction

ROOF SLAB AND ROOF BEAMS CONSTRUCTION

Ø  Formwork of roof beam and roof slabs are to be made.

Ø  This is the drawing of roof beams

Ø  Of the 30 cm height of beam, 10 cm is in the roof slab.

Ø  i.e., roof beams and slabs are interconnected.

Ø  Formworks of roof beam is done first. Then that of roof slab

Ø  It can be of woods or steel sheets.

Ø  Bamboo sticks or props are used for supporting the shutter.

Ø  It is firmly fixed on the grounds.

Ø  All gaps between the shutter sheets are closed to prevent the leakage of slurry during concrete.

Ø  Now steel works

Ø  For beams, we used 16mm dia bars

Ø  They are made at a height and then lowered to the shutter and placed above the cover block

Ø  8 mm dia steels used for roof slab

Ø  In our 1^st roof, we used 10mm and in the remaining 2 roofs, we used 8 mm.

Ø  Slab steels are placed correctly so that it can carry load safely.

Ø  They are tied using binding wires.

Ø  Cover blocks are provided at regular intervals

Ø  After finishing the steel framework, it should be checked by a professional engineer.

Ø  20 mm pipes are usually laid through the roof for the passage of electrical wires.

Ø  This is for ensuring the aesthetics.

Ø  Fan points are marked in the shutter using the plan.

Ø  Hooks of fan is laid there along with the pipes.

Ø  It is covered with paper so that it can be easily taken out after deshuttering.

Ø  Both openings of pipes are covered with insulation tape to prevent the entry of concrete and other particles

Ø  The other end of the pipe is given to the nearby walls.

Ø  Other electrical works are done later,

Ø  Some hooks are laid in parapets, some in rooms for cradles etc.

Ø  LED boxes if needed is also laid.

Ø  All these hooks and pipes are tightened to steel with the binding wires.

Ø  Clean the formwork by removing saw dust, wooden chippings, pipe pieces etc.

ROOF SLAB CONCRETE

Ø  It is the day of roof concrete

Ø  Concrete is prepared in mixer arranged in the ground

Ø  In one mix we used 1 bag of cement, 4 bowl Msand and 6 bowl of ¾ inch metal.

Ø  It can be transported either manually or by using hoist with bucket.

Ø  Water the formwork before placing concrete. Otherwise it will absorb water from concrete.

Ø  Concrete is placed in formwork using bowls

Ø  Thoroughly vibrated using mechanical vibrator.

Ø  10 cm is the required thickness of slab

Ø  A measured wood of 10 cm is used for this. Concreting is done up to this level

Ø  After vibration, using straight edge, excess concrete is stuck offby moving back and forth. And is levelled.

Ø  Then floats are used to remove further irregularities.

Ø  Aggregates are firmly embedded inside using it.

Ø  Then by using trowel, it is smoothened further.

Ø  Then it is allowed to harden

Ø  When it hardens, surface moisture is maintained by splashing or spraying water without force.

Ø  For proper curing small bunds are made in border using lean concrete.

Ø  Water can be filled at regular intervals and maintains temperature for good setting.

Ø  After 21 days, formworks were removed.

Ø  Carefully looking after the work and doing it in the proper way, will gives us the satisfaction of building a good house.

Ø  Hope you will review the work

Ø  Send your opinion and suggestions to my email id.

Ø  Thanks for watching.

Watch "Construction Steps of a House in India 2" on YouTube

https://youtu.be/XaHpTvUfnfQ