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Hand Book on Foundation,Formwork, Rebar &Concrete
Building Structure
Competency Center
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PREFACE
Construction industry in India is growing at faster pace
and the Buildings & Factories Operating Company (B&F
OC) is no exception in terms of number, size and volume
of projects. This growth throws challenges in terms of
delivery without compromising on Quality, Safety and
Sustainability. To meet this challenge, human resource is
the prime mover and it is essential to upgrade the skill and
knowledge level of engineers and front line supervisors to
the latest technology that our company adopts to sustain our leadership in the
market.B&F OCs entire business is grouped into three disciplines namely Structure,
Finishes and MEP. Building Structure Competency Cell (BSCC) of B&F OC
is created to provide total solutions to structure discipline in the areas of
Foundation, Formwork, reinforcement, Concrete and Pre-stressing.
BSCC has come out with a reference hand book on the methods and processes
adopted in construction of structure. I have gone through the book and found
it very useful for site engineers especially inUnderstanding the basics
Application in respective field
DOs & DONTs
Specifications & Standards
With this handbook they will be able to largely address the day to day issues
that they face and thereby become self-sufficient.
I am sure that the BSCC site engineers and Supervisors will make use of this
hand book to improve the operational efficiency which should translate into
improved quality at optimum cost.
I appreciate the entire BSCC teams who have put inefforts to make this book
a comprehensive tool.
(A.L.Sekar)
Vice President & Head RBBU.
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INDEXCONTENTS Page No.
ALUMINIUM FORM WORK
Introduction ...........................................................................................6Worksite Management ...........................................................................6
Assembly & Dismantling Process .............................................................9
Flowchart for Aluform ..........................................................................32
SLIP FORM
Introduction .........................................................................................34
Type of Slipform ...................................................................................36Assembly procedures ...........................................................................36
Tapering Slipform ................................................................................38
Assembly of stair tower .........................................................................39
Dismantling procedure .........................................................................40
Summary of Labour Productivity Norms .................................................43
Slipform Planning ................................................................................44
TUNNEL FORM
Aluminium Formwork Refurbishment .....................................................47
Plywood ..............................................................................................71
Form Release agent .............................................................................73
Formwork lift .......................................................................................74
Automatic Climbing System ..................................................................75
Hand tools required .............................................................................76
Guidelines for Formwork Engineer .......................................................33
Guidelines for Foreman/Charge hand ..................................................78
System Formwork Functions, applications& Safety. .................................79
REINFORCEMENT WORKS
Category of Reinforcements ..................................................................91Reference Indian standards ..................................................................91
Reference International Standards .........................................................91
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Hook & Bend Allowance .......................................................................92
Bar bending Schedule Format ...............................................................93
Minimum diameter required for Bending Former ...................................98
Cross-sectional area & Mass of Rebar ...................................................99
Checks ..............................................................................................100
Testing of Rebar .................................................................................101
Nominal cover ...................................................................................104
Tips on Cover ....................................................................................104
Tolerance of cover ..............................................................................104
Material for cover ..............................................................................105
Photographs (Rebar) ..........................................................................106Prefabricated cage photos ..................................................................109
Rebar tying machine ..........................................................................109
Splicing methods ...............................................................................110
Precautions ........................................................................................110
Splicing strengths ...............................................................................110
Reinforcement couplers ......................................................................110
Coupler photographs .........................................................................111Classification of test for Reinforcement couplers ...................................112
Reinforcement Binding .......................................................................113
Welding of Reinforcements .................................................................115
Precautions in Rebar activity ................................................................117
PILNG WORKS
Pile ...................................................................................................119
Classification .....................................................................................120
Factor governing Pile selection ............................................................112
List of Reference Codes ......................................................................125
Installation sequence
Driven cast in-situ piles ..................................................................126
Bore cast in-situ piles .....................................................................127
Characteristics of Bentonite suspension for BCIS piles ..........................128
Important things to be followed ..........................................................130
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Driven cast in-situ piles ..................................................................130
Bore cast in-situ piles .....................................................................131
Driven precast...............................................................................132
Load test on Piles ...............................................................................134
Types of Arrangements .......................................................................134
Vertical load test Arrangements ......................................................135
Lateral load test Arrangements ......................................................137
Pullout test arrangements ..............................................................138
Pile Integrity test .................................................................................140
PDA Test ............................................................................................140
O Cell Test. ......................................................................................142
CONCRETE WORKS
Cement .............................................................................................145
Physical requirement of Cement ..........................................................149
Mineral Admixtures ............................................................................150
Fly ash .........................................................................................150
GGBFS .........................................................................................154Micro silica& Metakoline ................................................................154
Aggregates ........................................................................................155
Mechanical Properties ...................................................................158
Grading Requirements ..................................................................159
Mixing of water ..................................................................................161
Admixture ..........................................................................................162
Concrete ...........................................................................................163
Grades of concrete .......................................................................164
Exposure conditions ......................................................................165
Batching ............................................................................................168
Mixing Time .......................................................................................170
Transporting Concrete ........................................................................171
Planning ............................................................................................172
Compaction ......................................................................................173
Vibration ...........................................................................................173
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Points to remembered in Compaction .................................................174
Finishing ...........................................................................................175
Curing ..............................................................................................177
Common defects in Concrete .............................................................179
Types of Surface defects ......................................................................180
Special concrete .................................................................................186
PRESTRESSING
Introduction .......................................................................................187
Definition ..........................................................................................187
Advantages of Prestressing .................................................................188Application ........................................................................................188
Materials management ......................................................................189
Reference Standard & codes ...............................................................191
Elongation & Modified Elongation Calculations ...................................192
Jack Pressure calculations ...................................................................192
Losses in Prestressing .........................................................................193
Properties of HT strand (IS: 14268-1995) ............................................193Methodology of Post Tensioning works ................................................194
Prestressing Equipments. ....................................................................197
Tendon Profile ....................................................................................198
Case study ........................................................................................199
Photos. ..............................................................................................201
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Introduction
Formwork Drawings
Site will be provided with a set of formwork drawings which entailed the
followings: -
Shell Plan Layout
Formwork layout drawings,
Wall panel Layout,
Slab Panel Layout,
Starter Block Layout,
Corner Layouts,
Beam Panel Layout,
Soffit Layout,
Staircase Layout,
Bracket and Soldier layout,
Miscellaneous Layout which includes sunken portion, upstand portion
etc,
Elevations and sections drawings indicating the location of formwork
panels and component,
Typical Fixing Detail drawings,
Location of Box outs and Transfer Box out drawings for transfer of
Formwork, etc.
Worksite Management
Logistic
Prior to the arrival of the containers from the disembarking point to the
project work site; a Stock Yard is to be properly allocated and set up for
the unloading of the formwork material and accessories.
This Stock Yard should preferably be located at close proximity or within
the compound of the project work site, properly fenced up and security
Aluminium Formwork
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shall be of up most priority due to the high residue value in the secondary
market for aluminum formwork material.
A Workshop area for maintenance of formwork material is recommended
to be set up at the project site to minimize the downtime in requisition of
replacement panels.
The proposed Stock Yard and Workshop area shall be flexible and re-
adjustable to suit the working environment and project work site. As a
result of the far away Stock Yard or Workshop area the project progress
will affect the targeted construction cycle time. (Ref Layout Drg No.: )
Upon arrival of formwork panels at Project Site, Site personnel shall ensure
that the panels are stacked and stored according to sizes and marking using
proper separator such as pallets for easy identification and allocation for
subsequent distribution. (Dry Mockup will be assembled as per schemes
at factory; this will eliminate the usual problematic discrepancies of odd
size panels which need to be fabricated at project site).
Manpower
BSCC - HQ shall provide the estimated manpower requirement for the
Project based on the quantity of formwork panels to be supplied to achieve
the required cycle time. This manpower requirement shall vary according
to the size of formwork use on the building.
However, the manpower requirement for other supplementary trades which
complement the formwork installation such as Mechanical & Electrical
(M&E) services and rebar works need to be taken into consideration also.
A joint effort of all operations from formwork installer, rebar, plumbing,
electrical and concreting workers need to be synchronized to achieve therequired cycle time.
Segregation and systematically allocation of duties for each formwork team
are required in ensuring optimization of productivity. Hence, each team
shall be delegated or assigned to do specific job tasks on a daily basis to
resemble a manufacturing production line. However, due consideration
should be used in determining the level of experience and compatibility of
persons when allocating tasks to minimize the risks.
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Safety
Control measures should be taken to identify and minimize the hazards
associated with work involving the assembly and dismantling of formwork
equipment such as falls from height, slips, falling objects, noise, dust and
manual tasks.
The external working brackets/platforms or scaffoldings should not be
used to stack materials or equipment. This will lead to the persons working
on it expose to additional hazards in relation to trips and slips or collapse
of the external working brackets / platforms or scaffolding.
Minimize the working heights for persons performing the assembly and
dismantling formwork.
Mixing of formwork components should be avoided to prevent unsafe
installation such as mixing pins and braces which may lead to collapse of
the formwork.
Do not allow drop stripping of formwork as it is an unsafe practice.
Partially assembled or dismantled formwork should be secured during
break time to prevent against overturning or collapsing due to strong wind
or accidentally / unintentionally knock over by workers.
Electrical safety should be implemented for the safe use of electrical
equipment.
Protruding flat ties or projecting nails should be removed immediately
with appropriate tools at dismantling stage.
Use of personal protective equipment by all persons working at work
areas (such as safety hardness, safety helmets, eye protection etc) should
be strictly implemented.
Accessories & Tools
Accessories (10%) extra will be supplied for the assembly and dismantling
of the formwork panels.
Sufficient tools required for assembling and dismantling will also be
supplied as per the attached list.
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Setting Up Level & Marking Of PositionThe project surveyor shall mark based on the approved construction drawings
to ensure that the gridline and level of the foundation level is properly set up,
marked for walls, column etc. Leveling must be checked prior to commencement
of formwork installation to ensure accurate positioning.
Formwork Panels
Cleaning of the surface and side panel of the formwork after each usage
shall be done immediately using proper tools.
Ensure that all front and side panel of formwork is properly coated with
recommended Form release agent that prevents from sticking and concrete
buildup aluminium form surfaces. It protects and prolongs the useful lives
of the aluminium formwork.
The following precautions shall be taken when applying the Formoil on
the aluminium panels.
The best results are obtained when a uniform application of Formoil is
applied immediately following stripping and subsequent cleaning of
the panels. Always ensure that the coated form surfaces are allowed
to dry prior to placing concrete.
Do not over apply. Excess Formoil can adversely affect performance
and should be picked up promptly with rags.
Prevent Formoil overspray from contacting reinforcing steel bars and/
or tensioning cables.
Installation Works of Rebar, M&E & Plumbing
The support works such as rebar, Mechanical & Electrical (M&E) and
plumbing are to commence immediately once the set up is done. The
same is to be ensured before installing the Aluminium formwork.
The support works for the slab section commence after the slab formwork
panels are assembled.
Cover Blocks should be fixed on both sides of the rebar section for
positioning and eliminate the rebar from resting on the surface of the
formwork panels.
Assembly Process
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Positioning of outlets for electrical switch boxes to its correct alignment can
be done by riveting the appropriate fit size mould to the formwork panels.
The electrical switch boxes are then securely cap to the fit size mould and
fasten by way of wiring to the formwork panels. Ensure that it is properly
secured to prevent grouting from building up in the switch boxes.
Assembly of Wall Formworks
Always commence wall erection from the external corner of the wall
section to ensure both joint external corner wall panels will support each
other for standing position. Pin and wedges are to be used to secure the
panels together. Always insert the pin from the inside out for easy removal
of pin after concreting.
The formwork panels wall positioning is securely placed on the marked
gridlines and level by way of fixing timber stoppers at the base of the
outer side of the formwork panels at interval of one (1) meter. This would
ensure that the formwork panels are not disposition during the concreting
process.
Once the initial wall corner panels are assembled, place the wall corner
panels on the allotted set up position.
Commence to erect simultaneously the balance of the wall panels from
either side of the external wall panel.
Proceed to assemble the internal wall corner. Place these panels into the
correct position on the lines which were set up by the surveyor. Proceed to
assemble the balance of the internal wall at both sides.
The internal and external walls are to be held together by flat wall tie with
wall tie sleeve and PVC cover. These wall tie sleeve and PVC cover are
to be cut for the exact length of the wall thickness. Flat wall tie are to be
coated with the Form Oil before each usage.
To determine and achieve the vertical accuracy of the formwork panels
assembled before concreting process, several methods such as plumb
bob, spirit level, theodolite equipment etc can be used. The simplified
method of using a plumb bob with a string attached to it which is then
suspended from the upper part of the formwork panels is used as a guide
to determine the deviation from the vertical alignment of the panels.
Additional wall panels or starter blocks (kickers) are fixed on the external
wall panels in accordance to the required height for the formation of the
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slab concrete. Check to ensure that the verticality of the Starter Blocks
(kickers) is correctly aligned.
The Starter Blocks (kickers) shall remain at its position for the subsequent
forming of next level wall.
Assembly of Beam & Slab Formworks
Fix the slab corner on top of the wall panels with round pins and wedges.
The position of the pins should be from top down to ease the dislodging
process.
The prop length and prop head is to be connected together for beam and
slab support.
Alu span mid beam and Alu span cantilever end beam are connected to
the Slab prop head using Beam Splice Bars. They are connected together
by long pins and wedges at bottom section.
The Aluspan mid beam sections are accurately position to enable the slab
panels to be connected systematically.
Commence to assemble the slab panels from the corner section of the
slab. Subsequently, fixed the whole slab area by pinning the slab panels
together with the Aluspan mid beam.
Assembly of External Working Brackets
External working platform brackets are used to provide a work area at the
external wall section.
Once the first level is completed and external formwork panels are
removed, fix the external working brackets to the first floor level at position
slightly below the kickers which are fixed on first floor external slab.The external working brackets are secured to the external wall section
from the inside using tie rods, nuts and bolts.
Once all the external working brackets are put in place, timber planks
and strips are placed on the floors and railings respectively to create an
external working platform for the assembly of the subsequent level of the
external formwork panels and kickers.
Another set of external working brackets are later fixed on the subsequentlevel using the method as prescribed above.
Once the subsequent level of external formwork panels are fixed, the
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external working brackets at one level below are removed and moved to
the subsequent level. This process is repeated until the completion of the
subsequent floors.
Identification of Formwork Assembled
A numbering sequence / stenciling shall be given for each panel and is
identified in accordance to unit area such as living rooms, Kitchens, Bed
rooms, bathrooms, common areas etc.
Color identification scheme while numbering on each section or area will
also eliminate the confusion that may arise due to the size. It can be
identified such that Blue is for Room 1, Red is for Room 2, Green is for
Living area etc.,
By practicing the use of numbering system in combination with the color
identification scheme, it have been proven to avoid confusion and assist
in the process of identification of panels position once they are transferred
to the next level/floor.
CONCRETING PROCESS
Pre-Check Before Concreting
Ensure that the position of the walls and column formwork are in
accordance with the set up marking.
Check to ensure correct spacing of props for slab formwork.
Check the verticality and horizontality level of the wall and slab panels
respectively.
Ensure that all pins, wedges and ties are properly secured and tightened.
Re-check the opening such as door and window panels are correct.
Re-check all propping stands to ensure its height are in accordance to
drawings.
Adequate bracing (if necessary) to ensure stability.
Ensure cover blocks are placed correctly.
Monitoring During Concreting Process
Ensure site coordinators are available and on stand-by during the
concreting process.
Always ensure that concrete pouring is distributed evenly throughout the
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wall sections before commencing to cast the slab level areas. This is to
prevent loading pressure on the formwork panels due to uneven casting.
Recheck the areas whenever cement slurry leakage is noted to determine
the cause of it. Remedy work should be done immediately to ensure the
concreting process is not affected.
During concreting, always ensure that immediate step is taken to remove
/ clean all the excess concrete that is stuck on the back of the formwork
panels. Non removal will result in the formwork panels getting too heavy
and also the scrapping task after the concrete has dried up becomes more
tedious.
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Dismantling of Wall, Column & Beam Formwork
Formwork panels shall be removed without damaging the concrete.
Reinforcement Bars or other tools shall not be used as a lever against the
concrete in removing the formwork panels. Only panel puller shall be
used for removing the wall panels.
The appropriate time for the stripping of formwork panels will vary
according to the environment and type of concrete used. The formwork
panels of the wall, column and beam section can be usually dismantled
after 12 hours. However, this process shall subject to approval of theproject structural engineer after taking into consideration the grade of
concrete used, additional props stand ordered, etc.
Always ensure that the wall section panels are removed first follow by the
column and beam sections.
For precautionary step, ensure that formwork panels are removed
systematically and due care is to be taken to prevent any damages to the
formwork panels and also finish surface of the concrete whenever possible.
For safety reason, ensure that no workers are facing the pin and wedges
when removing using hammer. Pin and wedges removed are to be
collected and placed in containers to minimize lost and replacement.
The dismantle formwork panels shall be transferred to the next level/floor
for subsequent assembly process via the slab opening or staircase areas
in an orderly manner and to the appropriate section/area immediately.
This will eliminate the confusion and congestion in the dismantling area
or level as a result of too many dismantled formwork panels lying on the
floor area.
As the formwork panels are pre-numbered and if color identification
scheme is implemented, the transfer of panels can be determined and
planned ahead according to the various sections / areas of one level/floor
to the subsequent level/floor.
Always ensure that all the formwork panels are to be properly cleaned
and applied with the Form release agent to protect the surface of the
formworks before re-used.
Dismantling Process
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For the external wall section, the Starter Blocks (kickers) on the upper
portion of the floor level shall remain intact to support and align the
next level/floor of formwork panels that are going to be assembled.
The assembly of the external formwork panels can be done by using the
external working platforms that are fixed to the wall areas.
Dismantling of Slab Formwork
The appropriate time for the stripping of formwork panels will vary
according to the environment and type of concrete used. The formwork
panels of the slabs section are usually dismantled after 36 hours. However,
this process shall subject to approval of the project structural engineer
after taking into consideration the grade of concrete used, additionalprops stand ordered, etc.
The Aluspans mid beams / end beams have to be removed first after
dismantling the wall panels. Proceed by removing the long pins and
wedges on the joint bars for the end and middle beams. However, the
prop lengths are to remain undisturbed during this process to lend support
for the weight of the concrete slab.
There shall be 2 sets of prop lengths to support the concrete slab. The firstset of the prop stands will only be removed when the assembly of the third
level/floor commences and also upon approval and consultation with the
project structural engineer.
Proceed t o dismantle the slab panels by commencing from the end of the
slab area. Once the slab panels are dismantled, continue to remove the
slab corners.
Removal of Flat Wall Tie & Wall Tie Sleeve
Flat wall Ties are used for the purpose of ensuring the thickness of the walls
and column are consistent. Flat wall ties are to be removed by using special
called Wall tie remover / extractor.
Subsequently, proceed to remove the wall tie sleeve which is embedded in the
walls and columns section by using nose player.
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Sequence No. 1
Form Release agent (Solvent based) to be applied on the surface of all thepanels before the assembly process.
Assembly Process
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Sequence No. 2
Outer Corner is fixed to External Wall Corner panel by round pin andwedge.
Assembly Process
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Sequence No. 3
Inner Corner is fixed to the Internal Wall panels by round pin & wedge. TheInternal and External Wall Panels are hold by Flat Tie with Tie Bar Shield in
between the panels.
Assembly Process
VERTICAL CORNER INTERNAL
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Sequence No. 4
Repeat Sequence No. 3 to complete the assembly of both the Internal andExternal Wall Panels.
Assembly Process
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Sequence No. 5
Install Slab Corner on the top portion of the Wall Panels with round pin &wedge.
Assembly Process
Slab Corner Internal
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Sequence No. 6
Aluspans mid beams / end beams and Prop head are combined by Beamsplice bar with long pin and wedge at the bottom section.
Assembly Process
BEAM SPLICE BAR
BEAM SPLICE BAR
Aluspan
Aluspan cantilever
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Sequence No. 7
Start the assembly of the Slab Panels from the Slab corner Internal.Subsequently, fill out the whole slab area by pinning the slab panels together
with the Aluspans (Comprises of Aluspans and cantilevers). Mid Beams / End
Beams
Assembly Process
Slab corner Internal
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Sequence No. 8
Additional Wall Panels (or Kickers) are fixed to the external Wall Panels to raiseto the appropriate height to contain the slab concrete when it is poured.
Assembly Process
ADDITIONAL WALL
PANEL / STARTER
BLOCK
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Sequence No. 9
Upon completion of the installation and fixing of the Wall and Slab Panels,a numbering sequence will be made for each of these panels with colour
identification scheme to differentiate each of the unit area such as bedrooms,
living room, bathroom etc. This numbering and colour identification scheme
will ensure that each panels can be determined as to their exact location once
they are tansferred to the next level for installation.
Sequence No. 10
Always ensure that wall ties, pins and wedges are properly installed and
secured before pouring concrete into the forms. Ensure that concrete pouring
is distribute evenly throughout the Wall Panels section before commencing tocast the slabs level area.
Assembly Process
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Sequence No. 1
After 12 hours, remove the Internal Wall panels by knocking out the wedgesand pins. The Wall Panels are to be moved to upper floor through the slab
opening as shown. The transferring of the panels should be done in a
systematically and orderly manner to ensure that the next cycle or level is not
affected. Since all the panels are numbered with different colour identification
scheme, these transfer process can be determined and planned in advance
according to section of the building such as Room 1, Room 2, Bathroom are
etc.
Dismantling Process
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Sequence No. 2
After removing the External Wall Forms (the starter Block (kicker) shouldremain undisturbed), the dismantled wall forms are moved to upper floor.
Access Scaffolding is use for transferring of external wall panels from the
ground floor level. For level 1 and above, an external working platform is
fixed to the external wall. The external wall forms from level 1onward shall
be supported by the kickers. (These steps are to be repeated from one floor
to another floor.)
Dismantling Process
Starter Block
Super plate
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Sequence No. 3
After removing the Wall Panels, proceed to the Slab Panels after 36 hoursby removing the long pins and wedges on the joint bars the end and middle
beam section.
Dismantling Process
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Sequence No. 4
Upon removing the Aluspans Mid Beams and Aluspan cantilevers End Beams,the prop shall remained undisturbed during this process to support the
concrete slab.
Dismantling Process
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Sequence No. 5
Proceed to strip the Slab Panels and transfer to the next level according to thedesignated area and installation sequence.
Dismantling Process
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Sequence No. 6
Strip the Slab Corner.
Dismantling Process
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Sequence No. 7
Pull out Wall flat Tie using Wall Tie puller and remove the Wall tie sleeve usingNose player.
Sequence No. 8
When the cube tests show that the slab concrete is sufficiently strong, the prop
together with the prop heads are removed and transferred to the next level.
Dismantling Process
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Flow Chart forAluform Work at Site
If not suitable
If suitable If not suitable
`
If work front is not ready
If work front is ready
1
2 3
4 4a
2a, 2b
5
6
7
8
7a
9
13
11
15 15a
16a
1a, 1b, 1c
3a
12
14
10
16
1919a, 19b, 19c, 19d
20212223
17 18
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Activity for the FlowChart Numbers
1. Receive Aluform materials.1a. Packing list, BOQ, and Formwork layout.1b. Tools.1c. Additional accessories.
2. Visual inspection.2a. Packing list & schemes.2b. Acceptance criteria.
3. Inform concern for any defects3a. Details of report.
4. Collect modification details.
4a. Fabrication drawings.5. Stock the material as per packing list.
6. Room wise segregation.
7. Dry mock-up.7a. Schemes.
8. Room wise numbering for identification.
9. Dismantling of mock-up.
10. Setting out.
11. Shift to work location.12. Shift to stock yard.
13. Actual assembly at work location.
14. Slab rebars & M&E works.
15. Final checking (Pre pour check)15a. Check list.
16. Concreting.16a. Pour card.
17. Post pour check.
18. Leveling and finishing.
19. De-shuttering19a. Removing pins and wedges.19b. Removing wall ties.19c. Removal of wall panels.19d. Removal of deck panels.
20. Cleaning of panels.
21. Fixing of working platforms with brackets.22. Erection of Safety posts / rails.
23. Applying Form release agent.
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Introduction
Slipform has been accepted as a precise construction technique within acomparatively short period of time an indication of its considerable popularity.
This popularity has in turn encouraged further research ensuring the adoption
of new methods and modern materials, which have firmly established
slipforming as an economical, rapid and accurate form of construction.
Now that it is properly developed, the technique can be applied to many
different forms of structure, including tapering formations with straight
or parabolic profiles incorporating constant reductions in wall thickness.
Traditional applications for slipforming are silos, chimneys, bridge piers,
water towers, special application like construction of pylons, lift core wall of
building, lining for tunnel shaft, framed structures etc.,
Principles of Slipform
Slipform construction, also referred to as sliding form construction, is similar
to an extrusion process. Plastic concrete is placed in the forms, and the forms
act as moving die to shape the concrete. Once the form has been filled with
fresh concrete and hardening has started the form is gradually raised by the
lifting devices on which it is suspended. The rate of movement of the form
is regulated, so that the forms leave the concrete after it is strong enough to
retain its shape while supporting its own weight. Pouring of concrete, tying of
reinforcement, fixing of openings/inserts etc are performed gradually from a
working platform.
An average sliding speed of 200mm an hour is common, rising to 300mm
an hour under the best conditions and 100 to 150mm an hour when large orcomplicated structures are being slipformed.
Design Considerations:
The slipform should be designed so that the loads to which its various
component parts are subjected are uniformly distributed, and the yokes are
loaded as uniformly and axially as possible to avoid their overturning. The
jacks should not be located in wall openings as for as possible. The loading
should not exceed the lifting capacity of the jacks. The loads acting on slipform
can be classified as follows,
Slipform
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BASIC LOADS
Dead load due to the components
Live loads due to Concrete
Friction between form and concrete
Workmen
Materials
Machinery
Other installations
Auxiliary load due to the way of application of live loads,
Crowds of workmen
Piles of materials
Shocks produced by material unloading
Accidental Loads
Wind pressure
Adhesion between concrete and form due to long interruption.
Friction due to incorrect position of form
Failure of one jack
Extraordinary Loads
Breaking of certain members of the slipform
Failure of two adjacent jacks
Minimum concrete strength required for slipform application,
2 Kgf / cm 2 - when releasing the form.
4 Kgf / cm 2 - when coming out from the form.
20 Kg / cm 2 - after 24 hours since pouring.
200 Kg / cm2 - after 28 days.
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Type of Slipform
The slipform can be broadly classified into,
Straight slipform.
Tapering slipform.
Slipform for special applications
Typical structures that are constructed using straight slipform technique are,
Silos
Cylindrical chimneys
Water tank shafts
Columns
Typical structures that are constructed using Tapering slipform are,
Conical chimneys
Ventilation stack
Tapered bridge piers
Typical structures that are constructed using Special slipform are,
Lift cores
Framed structures
Preheater building
RCC Pylons
Construction of block of flats, lifts and stair- well, bridge piers, preheater andRCC pylons for boiler supporting structure using slipform techniques comes
under special applications because of their complex sizes, shapes and loads
to be lifted along with slipform, like walkway trusses, etc. which is essential
for construction.
Assembly Procedures
Stright SlipformPosition the vertical and horizontal reinforcement with correct cover.
Casting of the starter. (min: 150 - 200mm)
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Check starter for the correctness in level and diameter.
Fix the inside and outside staging brackets/erect scaffold pipes, if
required.
Fix timber runners connecting the walkway brackets. / Level the surface
using cement mortar.
Check the level.
Tie the vertical and horizontal reinforcement upto shutter top height.
Mark the position of inside and outside yokes in the starter, starting from
the tower location.
Ensure that three sets of yokes are located in between two tower
verticals.
Align the panels and introduce steel washers at regular intervals to
maintain
4mm slope both inner & outer faces.
Fix top and bottom waler pipe. Fix external supports, both horizontal and
inclined to align the shutter.
Fix filler panels.
Repeat the operation 10 to 12 for outside and make sure that washers are
introduced at the bottom of shutters to achieve 4mm slope towards inside.
Fix the waler shoes, inside and outside yoke legs. Adjust waler shoe and
check the verticality on both faces
Keep timber supports between top & bottom walers at yoke location.
Align the form panel by external supports.
Fix the yoke beam generally two numbers at the bottom and one number
at top.
Check the level of yoke beams with spirit levels.
Fix the inside and outside walkway brackets.
Finish the final alignment by suitably adjusting the waler shoe bolts. Ensure
that all walers are touching the form panels. Provide packing wherever
required.Fix the flying tie rod assembly and support the center rings. Ensure uniform
tightness is maintained in all the spokes.
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Tapering SlipformPosition the vertical and horizontal reinforcement with correct cover.
Casting the starter. (Provide pocket or pipe sleeve in yoke locations to
accommodate tapered sleeves )
Check starter for the correctness in inclination level and diameter. Chip
and finish the same, if required.
Erect central tower using L&T HDT system and fix planks on the top after
aligning the top construction accurately.
Fix the centre frames with the help of scaffold pipes, if required.
Pre assemble the trusses and spiders after marking the location of inside
yoke leg, assemble with yoke legs, yoke beams, adjusting screws as per
initial setting diagram , erect them and provide support.
Check the level of truss.
Mark the position of inside and outside yokes in the starter starting from
the tower location.
Assemble the panels along with form supports with pre assembled
condition.
Fix top and bottom waler. Fix external supports both horizontal and inclined
to align the shutter.
Fix inside and outside consoles and upper outside console and fix
planks.
Fix the yoke beams at top & bottom.
Check the level of yoke beams with spirit levels.
Fix the top platform pipes with guard railings.Fix the jacks & turnbuckle jacks and finish the hydraulic connections.
Test for leakage in the line and jacks and replace, if required.
Fix water level tubes & check the platform level. Adjust if required.
Check the the final adjustment as per the initial setting diagram.
Fix the handrails.
Fix the tapered sleeves & jack rods.
Energise the slipform before filling the form and removing temporary
supports.
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Start the concreting after completion of all activities and checking the
availability of all materials as given in the planning for slipform.
Fix the inside and outside hanging scaffold and do the decking.
Tie the safety net.
Assembly of Stair Tower:
The verticality of the stair tower shall be checked only with plumb bob.
Stair tower shall be checked for verticality at every support location. If any
deviation is found it shall be corrected then and there, by adjusting support
length. The deviation in verticality shall not be more than 10mm for every
10M of height and maximum 50mm for the overall height.
CARE DURING SLIPFORM OPERATIONS:
1. Uniform layer of concreting.
2. Regular cleaning of shutters.
3. Penetration testing of concrete, for setting time.
4. Freeness of tapered sleeves.5. Periodical plumb readings.
6. Adjustment for tilt & twists.
7. Prevent overflowing of concrete.
8. Maintain a free board of 100 mm.
9. Uniform distribution of load on the platform.
10. Lowering of unwanted materials periodically.
11. Proper handling of lasers.
12. Cooling of jacks where the temperature is very high.
13. Protection of high pressure hose.
14. Protection of turnbuckle spindles.
15. Greasing of all moving parts / outside the shutters.
16. Ensure free movement of shutters, walers, intermediate form supports,
planks and handrails.
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17. Consistent quality of concrete.
18. Periodical checking of concrete slump.
19. Fixing of required setting time for concrete based on slipping speed.
Dismantling Procedure
Stright Slipform:
1. Provide coil nuts in the final layer of concrete approximately 300 mm
from top of concrete.
2. Fix dismantling brackets, handrails, finish planking and transfer the load
of slipform assembly to the brackets.
3. Remove the flying tie rod assembly and lower the same.
4. Remove the inside and outside hanging scaffold and shift the planks to
the staging brackets.
5. Remove the jacks and sleeves.
6. Remove the yoke assembly, which consists of yoke legs, yoke beams
and waler shoes.
7. Remove inside & outside walers.
8. Remove the wall forms, while removing the waler.
9. Extract the jack rods and grout the holes.
10. Remove dismantling brackets after completing other works.
Tapering Slipform:
1. Provide coil nuts in the final layer of concrete.
2. Fix dismantling brackets, handrails, and fix the planks.
3. Remove and re-locate the R.G.Hoist to the required location(if it is
there).
4. Transfer the load of slipform assembly and main truss to the wall.
5. Remove & re-fix the safety net with the temporary platform.
6. Remove the inside & outside hanging scaffolding.
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7. Remove all the hydraulic hoses, manifolds and the jacks.
8. Remove the intermediate form supports, spindles, turnbuckle, shutters,
form supports, wall thickness screws, radius screws and yoke beams.
9. Remove inside & outside yoke legs.
10. Dismantle the truss assembly.
11. Extract the jack rods and grout the hole
12. Lower the materials then and there.
13. Remove the dismantling platform.
Slipform Reinforcement:
The progress of slipform is mainly determined based on the time consuming
for concrete pouring speed and reinforcement tying. if any delay in these
two the progress will affect drastically. As the space available for tying the
horizontal is restricted in slipform, it is very essential to plan all the activities
well in advance and to be prepared before starting of slipform.
The following points have to be considered while making the schedule.
The length of vertical/horizontal bars should be restricted to 5 mtr. due to
the constraints in lifting and handing at heights.
The diagonal bars around openings should be avoided.
Wherever stirrups are used it should be in 2 pieces only.
It is not possible to have verticals in yoke locations and hence alternate
bars should be placed nearby.
Wherever concrete is taken through a chute the verticals below the chuteshave to be lapped with smaller lengths by means of welding.
The total requirement of reinforcement should be cut / bent and kept near
the slipform structure before starting slipform. The stocks should be kept with
proper tag for easy identification.
Refernce Standards And Codes
1. ACI 318- Building code requirements for reinforcement concrete.
2. ACI 304- Recommended practice for measuring, mixing, transporting
and placing concrete.
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3. ACI 313-77 R83 - Recommended practice for design and construction
of concrete bins, silos and bunkers for storage of granular materials.
4. ACI 347-78 - Recommended practice for concrete formwork.
5. ACI 313-77 - Allowable tolerance.
6. ASTM C 403-70 - Penetration resistance method of concrete setting.
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Summary of LabourProductivity Norms
Sl.
No.
Type of Work UnitNorms
In M.Hrs1 Erection of Access Tower (2.5 X 2.5 M) RM 32
2 Dismantling of Access Tower (2.5 X 2.5 M) RM 15
3 Erection of Stair Tower (2.5 X 2.5 M) RM 16
4 Dismantling of Stair Tower (2.5 X 2.5 M) RM 8
5 Straight Slipform Assembly YOKE SET 75
6 Straight Slipform Dismantling YOKE SET 55
7 Slipform Operation - Straight Slipform M2 1.22
8 Assembly of Pre-Stressed Silo YOKE SET 92
9 Slipform Concrete - Manual M3 22
10 Slipform Concrete - Rmc With Pump M3 15
11 Slipform Concrete - Rmc With Hoist M3 25
12 Slipform Reinforcement - Straight Slipform MT 65
13 Extraction of Climbing Rod RM 0.34
14 Taper Slipform Assembly - Upto 24 Yoke Set MT 56
15 Taper Slipform Assembly - 16 To 48 Yoke Set MT 49
16 Taper Slipform Dismantling - Upto 24 Yoke Set MT 49
17 Taper Slipform Dismantling - 16 to 48 Yoke Set MT 46
18 Re-Assembly of Slipform - Taper Slipform MT 78
19 Re-Assembly of Slipform - Straight Slipform YOKE SET 90
20 Slipform Operation - Taper Slipform M2 2.45
21 Slipform Reinforcement - Taper Slipform MT 90
22 Erection of R.G.Hoist NOS. 827
23 Re-Location of R.G.Hoist NOS. 1365
24 Dismantling of R.G.Hoist NOS. 675
25 Pre-Stressing Works in Silos MT 170
Note: The productivity norms will vary based on volume of work involved and numberof structures to be constructed in the project.
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The execution of slipform job requires a complete and detailed preparation
as many simultaneous and successive operations are involved. The method
of construction, preparation of scheme drgs., calculating the requirement ofslipform materials, equipment, tools & tackles, consumable, manpower etc
needs thorough planning.
It also involve mix design, admixtures to be added for the concrete,
reinforcement around openings and planning for other related works on the
slipformed structure.
Straight SlipformOn large site with several structures built with the same slipform, planning
includes
Work below slip form level
Detailed programme for the wall
Work involved in intermediate floors, if any.
Embedment/ pockets and other installations during slipform
Slipform Materials
The number of yokes for each silo is calculated based on the diameter of the
silo. The yoke to yoke distance is normally kept between 1.25 and 1.35 m.
Once the number of yokes required is calculated the list of materials can be
prepared from the master list. The requirement of jack rods depends on the
height of structure. Always keep 5% extra material as spare.
The length of yoke beams = Wall thickness + 1000 mm.
Normally 2Nos. Yoke beams at the bottom and 1 at the top are fixed.
Wherever yokes are used for supporting some lifting arrangements, there the
top yoke beams also shall be 2 no back to back.
Slipform Equipment:
The capacity of Jacks to be deployed is depends on the following loads:
Basic Loads:
Dead weight of yokes,
Slipform Planning
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Dead weight of Concrete lifting arrangements
Weight of Platform with 40thk plank
Weight of wooden Runners 125*75mm
Total Dead Load = X
Live Loads
Live load over platform @ 200kg/sqm
Weight of Concrete 0.5 cum
Weight of Steel (reinforcement, jack rod stacked on platform)
Weight of Equipment
Total Live load Y
Frictional forces @0.173kg/m (length along the wall sides) Z
Total Load on Slipform L = (X+Y+Z) * t
Required Jacking Capacity (W) should be with 1.4 factor
Note:- Jack shall not be loaded more than 80% of its capacity.
Concrete Equipment
The quantity of concrete required per meter height should be calculated
first. The slipping speed can be assumed based on the quantity of concrete ,reinforcement, pre-stressing and other related items. Rate of rise depends on
the above and setting time of concrete. Once the slipping speed is assumed
the concrete requirement per shift can be calculated.
Once the quantity per shift is known, with 25% spare capacity, the size and
number of mixing and lifting equipment shall be decided.
Consumable:The standard list of consumable is given along with master material list. The
quantity of electrodes, gas, grease, oil etc. can be given approximately. The
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wire rope required for hoisting to be calculated separately based on height of
the structure.
Timber Requirement
The requirement of timber is for the following areas.
1) Working platform 2) Masons platform 3) Runners for supports
4) Planks for the bracket platform if assembly is taken up from higher
elevation.
Working Platforms
Timber platform consisting of four parts
a) Supporting runners 5x 3x7 long & 6 long
b) Wooden planks 6 x 1 x 6 long.
c) Toe board size: 4 x 1 x 6 long
Manpower Requirement:
The requirement of labour for various activities can be calculated based on theproductivity norms, site conditions and type of structure.It is preferable to engage
one single agency for the entire slipform works in a project to have better control
over productivity and also optimum use of workmen with multi skill.
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Tunnel Form
Description of Half Tunnel Form
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Movement of Formwork
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Movement of Formwork
Movement of Formwork
Movement of Formwork
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Kickers
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Ties
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Protection Platforms
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Aluminium formworkRefurbishment
A) Process involved
a) Manual cleaning
A working table to be made and the Concrete lumps, dirt shall be cleaned by
the scrapper and wire brush.
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a.1) Tools Required
Ball Pein Hammer
Chisel
Scrapper
b) Machine Cleaning
b.1) Tools Required
GQ 4 Grinding Machine
4 circular buffing wheel
6 RUBBER BACK UP PAD
c) Dent Removal
Side rails are cleaned with GQ4
Grinding Machine, 4 circular
buffing wheel.
Remove the Dents if any in the
panel using a hammer and a
flat base plate. Make sure that
no point contact is there during
this process.
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d) Welding
After removing the dents,
inspect the panel for any
cracks in the welding joints.
If found it shall be welded.
Surface cleaning shall be
done with the sander disc,
ensure that smooth rendering
only is done.
d.1) Tools Required
TIG Welding machine
Welding coil spec :Aluminium filler wire 1.2 mm. Er 5356. Make: Indaco
e) Surface cleaning
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e.1) Tools Required
AG7 & AG4 GrindingMachine ( RPM 5000)
Sander Disc (80/120 Grade)
f) Lacquering and Stenciling
Safety items
Hand gloves
Nose mask
Ear plug / ear muff
Apron
Goggles white
Brushing viscosity of lacquer can be 30 sec. Surface to be touch dry with in 10min of application. Allow over night and use. Thinner- MCC 2507.
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Plywood
Plywood is an important commodity which plays a key role in the formwork
both in terms of quality and cost (10-13% of formwork cost). The finish of
the concrete surface where plywood is used as sheathing members is purelydependent on the quality of the plywood. Plywood is a manufactured wood
made up of thin sheets of woods and compressed together with a glue which
gives higher strength when compared to a normal wood.
Indian government has put stringent rules for cutting of wood which has
initiated the local ply manufactures to import the logs (poplar and birch wood)
from various foreign countries for the production of plywood. The performance
of the plywood (for formwork application) is mainly based on the glue whichthey use for binding (mostly wood species used by all the manufactures are
common).
Plywood shall be tested at site premises before accepting. The testing facilities
are established in all major projects. Incase if the same is not available
respective site representative can contact the Cluster BSCC in charge for
extending the support.
Plywood procurement is centralized in order to deliver a quality product to the
projects at a competitive rate.
Plywood request format shall be filled and sent to the respective cluster BSCC
in-charge for clearing the procurement. Cluster BSCC in-charge will in turn
take concurrence from Head BSCC.
Now about 60 to 70% of the plywood requirements for the projects are serviced
from china and the followingare the details pertaining to the
same
Item Code 765610020
Repetitions 8 to 10
Price approx 20% cheaper
than domestic ply
Delivery period 60 to 65 days
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Form Release Agent
Approved Form Release Agents
Its a management decision that apart from these solvet based form release
agent other products cannot be used until unless it is approved by Cluster /
HQ BSCC.
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Formwork Lift
A system which complements the ability of Table form to do faster construction.
It is turning out to be one of the most important equipments which will be
extremely useful in improving the functional aspect of L&Ts trademark Table
form System. Till now, our Table form System was totally dependent on Crane,
especially while shifting the Table vertically from one Floor to the next. RCS
would not only help in drastically reducing this dependability on Crane but
also have a positive impact on the Labour Productivity subsequently helping in
reduction of Cycle time. Though the system was procured from the formwork
supplier the self climbing equipment was indigenously developed by BSCC-
HQ which further eliminated the crane requirement for floor to floor shiftingof RCS.
A project site will be debited with a internal hire charges of ` / Month
Cycle time
Labour Productivity -
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ACS - Automatic Climbing System
Self Climbing System ACS - Fields of Application
Self Climbing System ACS - Hydraulic System
Self Climbing System ACS
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Hand tools required (work place)
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ROLES & RESPONSIBILITIESOF FORMWORKENGINEER AT SITE
1. Preparation of Formwork programme based on the overall construction
programme
2. Finalization and coordination of Shuttering Scheme
3. Ensuring effective and proper utilization of shuttering and staging
materials
4. Planning and allocation of materials / labour / Plant & machinery for
formwork activities in coordination with concerned persons at site
5. Educating sub-contractors on System formwork
6. Making mock-up of various System formwork
7. Periodical reconciliation of formwork materials
8. Preparing S-6 A schedule (requirement / release) and sending the same
to Cluster Office
9. Preparing stock statement of formwork materials both in Units and in
Nos., with area of shuttering done category-wise, Plywood / Timber
procured during the quarter / till date and Productivity report.
10. Maintain close interaction with stores and site people for proper
accounting of materials
11. Despatch and receipt notes to be sent to Cluster Office
12. Making of purchase requisition for Plywood and Timber after thoroughly
analyzing the number of repetitions
13. Receipts of plywood / formwork materials to be acknowledged after
quality checks to Cluster Office on monthly basis
14. 100% materials reconciliation at the end of the job
15. Looking after pre-despatch maintenance
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16. Ensuring that despatched materials are in usable condition.
17. Sending monthly reports to Cluster office.
ROLES & RESPONSIBILITIESOF SITE FOREMAN / CHARGEHANDS
1. Material Accountability right from the materials receipts at site to despatch
to other site after the completion of the job.
2. Small items have to be issued to the sub contractors from stores and
make them responsible for those items. For their sake, tool box can be
issued. These items have to reconcile after the completion of the job.
3. Proper usage of the formwork materials and avoid the misuse (usingbracing as leverage) of the same.
4. Ensure proper house keeping at site as well as the maintenance
(greasing / oiling after deshuttering etc.) of the formwork materials
5. Deshuttering right on time to achieve maximum number of repetitions of
formwork materials.
6. Optimum use of nails in H beam.
7. Quality in works carried out at site so that tolerance should within
tolerance limit.
8. Formwork labour productivity should be monitored closely to achieve the
management goal.
9. Training of Labour and Sub contractor workmen at site either by mock
up or classroom programme by drawing sketches.
10. Adoption of safety standards while working by fully equipped with
PPE and using the complete system at site (do not miss any bracing /
connecting pin / locking pin etc.).
11. Use of stocking pallets.
System formwork functions, applications& Safety
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1.Foundation formwork(All steel)
Functions/Salient features
1. All the components are made out of steel
2. No timber is used
3. Easy to assemble
4. Higher labour productivity
5. High quality concrete surface finish
6. Suitable for side formwork of sub structures .
7. Capable of withstanding the concrete pressure of 10KN/sq.m
Sequences of assembly
1. Materials stocking near to layout
2. Cleaning and oiling
3. Layout marking
4. Floor forms positioning
5. Accessories fixing
6. Line and verticality checking
7. Concreting
8. Deshuttering
Safety appliances required
1. Safety helmet
2. Manila rope 20 mm or 25 mm
Safety precautions
1. During transporting and stocking the materials proper care has to betaken
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2. While lowering the materials from ground level to down level additional
care has to be taken
2.Wall/Column formwork
Functions/Salient features
1. System can be done by Crane and Manual
2. Using standard component wide range of plan configurations are
possible
3. High strength tie system bear large concrete pressure and avoid load
bearing struts
4. Provisions for fixing scaffolding platform and alignment units built-in
5. Offsetseliminated producing good concrete finish
Sequences of assembly
1. Materials stocking near to layout
2. Cleaning and oiling
3. Layout marking/starter casting and layout checking
4. Panel positioning
5. Accessories fixing and alignment
6. Line, level and verticality checking
7. Concreting
8. Deshuttering
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safetynet for taller structures
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4. Manila rope 20 mm or 25 mm
Safety precautions
Crane operation
1. Sling capacity and quality of sling has to be checked
2. D Shackle capacity has to be checked
3. Experienced signal man has to be engaged for propersignaling to the
crane operator
4. Ensure that there is no loose material on the panels or platforms
5. Before lifting the panel, necessary pre checking has to be done on the
panels.
Manual operation
1. Use the necessary personal protection appliances such as helmet and
belt.
2. Use the proper tool for adjusting the panel height and line
3. Flex system
Functions/Salient features
1. System can be used up to floor height of 4.40 mtr.
2. Removable folding tripods make selected individual props self
-standing
3. Flexibility in adjusting the individual prop height and spacing between
props
4. Components are easy to handle manually
5. Steel members can also be used for decking
7. Eliminating the skilled labour at site
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Sequences of assembly
1. Materials stocking near to layout
2. Prop layout marking
3. Main Prop positioning with tripod
4. Intermediate props positioning with supporting head
5. Placing of fourway head, primary layer beam and secondary layer
beam
6. Levelingof beams with the help of props
7. Placing of plywood.
8. Levelling of seathing and checking
9. Cleaning and oiling
10. Concreting
11. Dismantling
12. Cleaning
13. Transporting and stocking
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures whereever it is necessary
4. Manila rope 20 mm or 25 mm wherever it is necessary
Safety precautions
1. All the main props shall be fitted with folding tripod
2. All the indermediate shall be fitted with supporting head
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3. Do not use tor steel in place of locking pin
4. In ground level work , proper earth compaction and necessary bearing
below the prop shall be given
4.Heavy duty tower system -HDT
Functions/Salient features
1. Higher loading capacity of 250 KN and needs bracing at every 6 m in
height both horizontal directions with permanent other towers
2. Can be assembled in plan dimensions of 1524x1524 mm and
2250x1524 mm, by choosing the type of bracing both configurationswith four legs of 62.5 KN capacity each.
3. Height adjustments up to a minimum of 800 mm is possible by utilising
both top and bottom tower spindles
4. Easy to obtain plumb using tower spindles
5. Tower as a whole can be shifted(rolled) manually by attaching transport
devices to the legs
Sequences of assembly
1. Materials stocking near to layout
2. Tower layout marking
3. Frame fixing with necessary accessories at bottom and fixing of bracings
between the frames
4. Placing of necessary accessories at top with U head and steel waler
5. Placing of beam span and H-Beams
6. Levelling of beams
7. Placing of bottom/sheathing
8. Leveling of bottm/sheathing
9. Checking of levels and verticality
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10. Cleaning and oiling
11. Concreting
12. Dismantling
13. Cleaning
14. Transporting and stocking
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures whereever it is necessary
4. Manila rope 20 mm or 25 mm wherever it is necessary
Safety precautions
1. Every 6 mtr interval bracing has to be fixed with permanent structure or
tower to tower
2. Ground level earth has to be compacted well for better loading
3. Materials conditions has to be checked and badly damaged frames and
bracings to be avoided
4. Do not use tor steel in place of locking pin
5. Stair towerFunctions/Salient features
1. Safe and convenient access up to 100 mtr height in the form of stair with
suitablebracing with bracing with permanent structures every 6 mtr
2. Structural skeleton of HDT with a few additional accessories.
3. Can be handled as a single unit with a crane
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Sequences of assembly
1. Materials stocking near to layout
2. Tower layout marking
3. Frame fixing with necessary accessories at bottom with foot plate , spring
locking pin and tower spindle
4. Placing of 1.20 m frame with necessary bracing for one level
5. Checking of level and verticality for one level
6. Fixing of stair brackets ,grid iron ,connection angle , idermediate railing
and inner hand railing7. Every 6 mtr height necessary bracing with permanent structure
8. Dismantling
9. Cleaning
10. Transporting and stocking
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures whereever it is necessary
4. Manila rope 20 mm or 25 mm wherever it is necessary
Safety precautions
1. Every 6 mtr interval bracing has to be fixed with permanent structure
2. Ground level earth has to be compacted well for safe loading
3. Materials conditions has to be checked and badly damaged frames and
bracings to be avoided
4. Do not use coir string or binding wire in place of M 10 bolt and nut with
grid iron
5. Do not omit any bracing
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6. Access scaffolding
Functions/Salient features
1. Exclusively used for scaffolding purpose up to 40 mtr height braced atevery 6 mtr with structure
2. Frames are lighter in weight and 1.0 mtr in width
3. This provides free movement for workmen without any obstuction at all
levels
4. Bracing 2H-225 serves as an essential bracing for stability as well as
hand rail on the face away from the strutures
Sequences of assembly
1. Materials stocking near to layout
2. Tower layout marking
3. Frame fixing with necessary accessories at bottom with LD foot plate ,
spring locking pin and LD tower spindle
4. Placing of frame with necessary bracing for one level
5. Checking of level and verticality for one level
6. Fixing of platform hanger and walk way 225
7. Every 6 mtr height necessary bracing with permanent structure
8. Dismantling
9. Cleaning
10. Transporting and stocking
Safety appliances required
1. Safety helmet
2. Safety belt
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3. Safety net for taller structures whereever it is necessary
4. Manila rope 20 mm or 25 mm wherever it is necessary
Safety precautions
1. Every 6 mtr interval bracing has to be fixed with permanent structure
2. Ground level earth has to be compacted well for safe loading
3. Materials conditions has to be checked and badly damaged
frames,walkway 225 and bracings to be avoided
4. Do not use coir string or binding wire in place of Platform hanger
5. Do not omit any bracing
7. Lift shaft formwork
Functions/Salient features
1. Provides a platform for shutter and workmen inside the closed area of
liftwell and a deshuttering mechanism for stripping of formwork without
dismantling the panels and seathing
2. Panels can be lifted integrally in deshuttered position along with platform
and erected for next pour
3. A few components are required in addition to all components of wall//
column formwork
Sequences of assembly
1. Materials stocking near to layout
2. Erect the platform in the pocket loations in the inside wall face with
climbing pawl arrangements
3. Level the platform with the help of bolt given in the climbing pawl
4. Erection of inner wall panels with the necessary accessories including tie
arrangements
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5. Erection of outer panels with necessary accessories
6. Checking of dimensions,levels and verticality
7. Concreting
8. Releasing of inner panels for minimum of 20 mm on all the four sides
9. Lifting of inner panels with platform for next level
10. Lifting of outer panels
11. Cleaning and oiling
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures where ever it is necessary
4. Manila rope 20 mm or 25 mm where ever it is necessary
Safety precautions
1. Sling capacity and quality of sling has to be checked
2. D Shackle capacity has to be checked
3. Experienced signal man has to be engaged for Proper signaling to the
crane operator
4. Ensure that there is no loose materials on the panels or platforms
5. Before lifting the panel , necessary pre checking has to be done on the
panels.
6. Ensure the gap before lifting the inner panel platform
8.Framed formwork Frami
Functions/Salient features
1. Sturdy and torsion proof hollow sectioned steel frame
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2. Hot-dip galvanished for high Durabilty
3. High grade 15 mm thick film coated sheathing for high wear resistance
4. Easy to fasten accessories
5. Integrated handles for easier handling
6. Permissible concrete pressure on formwork 40 KN/sqm
7. Can be used for foundation , column and wall
Sequences of assembly
1. Materials stocking near to layout
2. Place the panels with all the necessary accessories as required
3. Check the dimension,level,line and verticality
4. Concreting
5. Releasing of inner panels for minimum of 20 mm on all the four sides
6. Lifting of inner panels with platform for next level
7. Lifting of outer panels
8. Cleaning and oiling
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures where ever it is necessary
Safety precautions
1. Provide the tierod only where the given the provision is given
2. Do not omit any components
3. Framiadj strut 260 is to be anchored properly
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9.Climbing formwork
Functions/Salient features
1. Large area form work can be taken up
2. Any height is possible
3. High degree of safety as on the ground
4. Faster and economical
5. Can be used for inclined structures also
6. Formwork is safely anchored to concrete at all times
7. Simple system of working platforms
Safety appliances required
1. Safety helmet
2. Safety belt
3. Safety net for taller structures where ever it is necessary
Safety precautions
1. Platform timbers should be free from cracks ,fungus attack and dead
knots
2. Hand rails pipes are to be fixed properly
3. Stop anchor threaded length shall be 55 mm inside the anchor cone
4. Climbing cone threaded bore length shall be ------
5. Plat form shall be free from gap between timber joints
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REINFORCEMENT WORKS
Category of Reinforcements
Carbon steel bars (plain and deformed).Cold reduced plain and deformed steel wire fabric.
Stainless steel bars and fabric.
Galvanized carbon steel bars and fabric.
Epoxy coated carbon steel bars.
Fiber Reinforced Polymer (FRP) rebar- [Non steel reinforcement]
Reference Indian Standards:
IS 1786 - 2008 - Specification for High Strength Deformed bar and Wires
for Concrete Reinforcement.
IS 432 PART 1- 1982 - Specification for Mild steel and Medium tensile
steel bars and hard drawn steel wire for concrete reinforcement
IS 432 PART 2 -1982-Specification for Mild steel and Medium tensile steel
bars and hard drawn steel wire for concrete reinforcement.
IS 2502 -1963 - Code of practice for Bending and Fixing Bars for Concrete
Reinforcement.
SP 34 -1987 Hand book on Concrete Reinforcement and Detailing
Reference International Standards.
BS 4449 Carbon steel bars for concrete.
BS 7295 Fusion bonded epoxy coated steel
BS6744 Stainless steel
BS 4483 Steel fabric
BS 4482 Hard drawn wire
BS 8666 Scheduling dimensioning, bending and cutting of steel
reinforcement for concrete - Specification
ASTM A 615 for carbon steel rebar.
ASTM A 706 for seismic rebar.
ASTM A 955 for stainless steel rebar.ACI 440 for FRP bars
DIN 488 Reinforcing steels
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How to Calculate Hook & Bend Allowance
REBAR TYPE
Bar Diameter,
d 25mm
Bar Diameter,
d > 25mm
k
ValueHook Bend
k
ValueHook Bend
Mild Steel 2 9d 5d 3 11d 5.5d
Medium Tensile Steel 3 11d 5.5d 4 13d 6d
Cold Worked Steel 4 13d 6d 6 17d 7d
Note:
All the Value is to be rounded off to nearest 5mm.
If the calculated result is
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Calculated Hook & Bend Allowance:
Nom
inalSize
of
Bar
(D)
Hook Allowance (H) Bend Allowance (B)
Mild Steel
Medium
Tensile
Steel
Cold
Worked
Steel
Mild Steel
Medium
Tensile
Steel
Cold
Worked
Steel
Min
Rec
om
md.
Min
Rec
om
md.
Min
Rec
om
md.
Min
Rec
om
md.
Min
Rec
om
md.
Min
Rec
om
md.
5 75 - 75 - 75 - 75 - 75 - 75 -
6 75 - 75 - 75 - 75 - 75 - 75 -
8 75 - 90 - 105 - 75 - 75 - 75 -
10 90 - 110 - 130 - 75 - 75 - 75 -
12 110 - 130 - 155 - 75 - 75 - 75 -
16 145 - 175 - 210 - 80 - 90 - 95 -
20 180 - 220 - 260 - 100 - 110 - 120 -
22 200 - 240 - 285 - 110 - 120 - 130 -
25 225 - 275 - 325 - 125 - 140 - 150 -
28 250 310 310 365 365 475 146 155 155 170 170 195
32 290 350 350 415 415 545 160 175 175 190 190 225
36 325 395 395 470 470 610 180 200 200 215 215 250
40 360 440 440 520 520 680 200 220 220 240 240 280
45 405 495 495 585 585 765 225 250 250 270 270 315
50 450 550 550 650 650 850 250 275 275 300 300 350
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LARSEN & TOUBRO LIMITED -ECC DIVISION
QUALITY FORMAT
BAR BENDING SCHEDULE
PROJECT : DATE :
AREA/BUILDING :
DESCRIPTION OF WORK :
TIME
:
DRG.REF . :
MEMBER
BAR
NO.
DIA. OF
BAR
NO.PER
MEMBER
NO.OF
MEMBER
TOTAL