The document presents an overview of formwork construction techniques, detailing the materials, design, and requirements necessary for effective use, including quality, safety, and economy considerations. It outlines different types of formwork for various structural members such as walls, columns, and slabs, along with the importance of proper assembly, removal, and maintenance practices. Additionally, it discusses cost factors associated with formwork and highlights the advantages of using steel formwork over traditional materials.

1. PRESENTATION
ON“FORMWORK”
CON S TRUCTION
TECHNIQUES
BY
Nishant Singh
Kushwah
G E C , Aj m e
r
17-Apr-19 N S Kushwah

2. What is Formwork?
oFormwork is a mould including all supporting structures, used to
shape and support the concrete until it attains sufficient strength to
carry its own weight.
oIt should be capable of carrying all imposed dead and live
loads apart from its own weight.
Formwork is commonly made of
o Steel
o Timber
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3. TIMBER
FORMWORK
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4. STEEL
FORMWORK
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5.  Formwork has been in use since the beginning of
concrete construction.
 New materials such as steel, plastics and fibreglass are used
in formwork.
 Greater attention is being given to the design,
fabrication, erection and dismantling of formwork
 Formwork is designed according to The ACI document SP-4.
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6. Qualities of
Formwork
 It should be water tight.
 It should be strong.
 It can be reusable.
 Its contact surface should be uniform.
 It should be according to the size of
member.
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7. • In order to successfully carry out its
function, formwork must achieve a
balance of following requirements:
• Containment
• Strength
• Resistance To Leakage
• Accuracy
• Ease Of Handling
• Finish And Reuse Potential
• Access For Concrete
• Economy
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8. • Containment: formwork must be capable of shaping and
supporting the fluid concrete until it cures.
• Strength: formwork must be capable of safely withstanding
without distortion or danger the dead weight of the fluid
concrete is placed on it, labour weight, equipment weight and
any environmental loadings.
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9. • Ease of Handling: form panels and units should be designed
so that their maximum size does not exceed that which can be
easily handled by hand or mechanical means.
– In addition all formwork must also be designed and
constructed to include facilities for adjustments, levelling,
easing and striking without damage to the form work or
concrete.
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10. • Economy: all the formwork is very expensive. On average about 35% of
the total cost of any finished concrete unit or element can be attributed to
its formwork; of this just over 40% can be taken for material for
formwork and 60% for labour.
– The formwork designer must therefore not only consider the
maximum number of times that any form can be reused, but also
produce a design that will minimize the time taken for erection and
striking.
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11. Major objectives
considered in
formwork:
 Quality
 Safety
 Economy
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12. so that they have
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 Quality:
Forms must be designed and built with sufficient stiffness and accuracy so that the
size, shape, position, and finish of the cast concrete are maintained.
Safety:
Forms must be built sufficient strengthand factor of safety
the capable of all supporting loads.

Economy:
Forms must be built efficiently, minimizing time and cost.

13. Requirements of
formwork:
 Material should be cheap and re usable,
 It should be practically water proof, so that it should
not absorb water from concrete,
 Swelling and shrinkage should be minimum,
 Strong enough to with stand all external loads,
 Deflection should be minimum,
 Surface should be smooth, and afford easy striping,
 Light in weight, so that easy to transfer,
 Joints should be stiff, so that lateral deformation and
leak is
minimum .
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14. Three stages in the
process :
a) Assembly and erection .
b) Concrete placement.
c) Stripping and dismantling.
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15. • Formwork detail for
different structural
members
In concrete construction formwork is
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commonly provided for the following
structural members.
o Wall
o Column
o Slabs & Beams
o Stairs
o Chimneys
o Water tanks
o Cooling TNoSwK
uesrhsw
a
h

16. • Formwork for Wall
 It consists of
• Timber sheeting
• Vertical posts
• Horizontal members
• Rackers
• Stakes
• Wedges
 After completing one side of
formwork reinforcement is
provided at the place then the
second side formwork is
provided.
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17. • Formwork for Column
• It consists of the following
– Side & End Planks
– Yoke
– Nut & Bolts
• Two end & two side planks
are joined by the yokes
and bolts.
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18. • Formwork for
columns
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19. • Formwork for S labs &
beams•:
It consistsof
– Sole plates
– Wedges
– Props
– Head tree
– Planks
– Batten
– Ledgers
• Beam
formworkrests on
head tree
• Slab form work
restson
battens and joists
• If prop height
aremore than 8’
provide horizontal
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20. • Lintel or Beam
Formwork:
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21. • FORMWORK FOR S
LAB:
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22. • FORMWORK FOR STAIRS:
• It consists of
– Vertical & inclined
posts
– Inclined members
-- Wooden Planks or
sheeting
– Stringer
– Riser Planks
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23. • FORMWORK FOR STAIRS:
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24. • FORMWORK FOR SPIRAL
STAIRS :
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25. • FORMWORK FOR CHIMNEYS:
For tall chimneys two types of
forms techniques are in generally use in our
country
a) Jump form
b) Slip form
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26. 17-Apr-19 N S Kushwah

27. • Removal of
formwork:
Time of formwork removal depends on the following factors
1. Type of Cement
1. Rapid hardening cements require lesser time as compared to
OPC (Ordinary Portland Cement)
2. Ratio of concrete mix
1. Rich ratio concrete gain strength earlier as compared to
weak ratio concrete.
3. Weather condition
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1. Hydration process accelerates in hot weather conditions
as compared NtoScoKluds
hanwda
hhumidweather conditions.

28. Time of Removal of
formwork:
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29. • First free end's
support
should be removed.
• And then from right to left
it should be proceed.
• If we are removing from
the mid span then it will
act as a prop cantilever
.
Cantilever slab
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30. • In simply supported we
have to remove the
support from the mid
span to the ends.
• To meet the design
behavior.
S imply supported slab
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31. • Maintenance of formwork:
• Due to continuous use wooden planks &
steel plates surfaces become uneven and require
maintenance.
• For wooden formwork use cardboard or
plastic fiber board. Bolt hole places must also be
repaired.
• For steelformwork plates must be leveled
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32. • Cost of formwork
 For normal works cost of formwork is about 30%-40% of the concrete cost.
 For special works cost of formwork is about 50%-60% of the concrete cost.
 Formwork cost is controlled by the following factors
• Formwork Material cost
• Formwork erecting cost
• Formwork removal cost
• Formwork jointing cost (Nails and Cables)
• Labor charges.
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33. • Advantages of steel form work:
 It can be used for a no. of
times.
 It is non absorbent.
 Smooth finish surfaceobtained.
 No shrinkage of formwork
occurs.
 Easy to use.
 Its volume is less
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34. • LOADS ON FORMWORK:
• Dead load
 Self weight of formwork
 Pressure and loads from fresh
concrete
 Reinforcement
• Imposed load
 Construction workers
 Stacking of materials
• Horizontal loads
• Environmental loads
 Accidental loads
 Wind loads
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35. • References
• R.C.C Design by B.C.Punmia
• R.C.C Design by H.J.Shah
• Formwork Design Section 1500
• Doka Formwork Design
• Design of safe timber structures by Eva
and Tomi Torrati
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