Page 1
259 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
Use of Plastic in Formwork
Abhishek Balvir Patil
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Akhilesh Anil More
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Akshay Ashok Patil
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Akshay Sunil Lohar
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Mikaj Shahajhan Sutar
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur.
Prof. Dr. G. M. Malu
Head of Departments
Civil Engineering
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Sayali Kiran Shirgave
Student, (U.G.)
Dr. J.J. Magdum College of
Engineering, Jaysingpur
Abstract
In this paper, has been discussed plastic formwork system has been introduced and all the aspects of plastic
formwork. The large amount of deforestation has occurred in recent past causing environmental imbalance to our
ecosystem. As a preventive measure to stop deforestation we should find alternative to wood formwork. In this point of
view ‘PLASTIC FORMWORK’ is only possible solution to this problem as it is recyclable, reusable and eco-friendly
alternative. That’s why the plastic formwork introduced to replace the traditional formwork. Plastic formwork is a new
innovation is formwork industry, it is famous for its light weight, speedy construction and in accuracy in work. Today
almost over 350000 sq m of formwork is being used for construction purpose all over the world. In our country plastic
formwork has been used on many construction projects and it has been proved to be economical. Plastic formwork has
been widely used in Gulf countries, Europe, Asia as well as all other parts of world. This technology is mostly suitable
for huge housing projects to be completed in short period of time, where columns, beams, slab sizes are standard. This
technology gives more accurate results and good quality of construction in optimum cost and minimum time.
Keywords:Plastic formwork, Joist, Props, Ligaments and Joints.
INTRODUCTION
Formwork is the temporary structure that enables molding of concrete into desired shape, holds it in the
correct position until it has hardened sufficiently and is able to support the loads imposed on it. The structural
system of temporary supports that holds the formwork in position is termed as false work. Formwork is also
an effective means of curing when it is left in place. The operation of removing the formwork is known as
stripping. Stripped formwork can be reused. Reusable forms are known as panel forms and non-usable ones
are called stationary forms.
The erection of formwork is a time consuming process and cost of formwork (material + labour) could
sometimes be as high as 50% of the cost of the concrete structure. The failure of formwork systems during
construction, causing monetary and time loss, sometimes grave injuries and death, are not uncommon.
Efficient design of these temporary structures play critical role in reducing the cost and ensuring safety. [1]
Page 2
260 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
Formwork, which holds and supports wet concrete till such time it cures, is a very vital element in concrete
construction. With the globalization of Indian economy and introduction of multinationals in India for the
construction and nations pride program of golden quadrilateral, it has become foremost to have speedy
construction and timely completion of projects. Now days, low waste modern formwork systems for
superstructure construction are commonly adopted. Formwork system affects on the cost, time, and quality of
project delivery. But still these formwork systems are not much used in India and most of the contractors do
not like to shift to the latest technology as they have the doubt of facing losses in the project and they are very
much familiar with the existing formwork type, the conventional type. At the same time they believe that
these formwork systems are bit expensive.[2]
1. CLASSIFICATION OF FORMWORK AND FORMWORK SYSTEMS
Different types of construction require the use of different types of formworks. The strength of the building
components, the speed at which building is constructed, and the cost of construction will depend to a great
extent upon the appropriateness of formwork used in the construction. Formwork can be classified according
to a variety of categories, relating to the differences in sizes, location of use, construction materials, nature of
operation, or simply by the brand name of the products. Major formwork systems are as follows:
1. Traditional Timber Formwork Systems
2. Re-Usable Plastic/PVC/Aluminium Formwork Systems
3. Table form/Flying form systems
4. Jump form Systems
5. Slip form Systems
6. Permanent Insulated Formwork Systems
2. CONVENTIONAL FORMWORK AND NEED FOR MODERN FORMWORK
2.1 Conventional Formwork
This usually consists of standard framed panels tied together over their backs with horizontalmembers called
waling. The waling is provided with the basic function of resisting the horizontal force of wet concrete. One
side of the wall formwork is first assembled ensuring that it is correctly aligned, plumbed and strutted. The
steel reinforcement cage is then placed and positioned before the other side of the formwork is erected and
fixed. Plywood sheet in combination with timber is the most common material used for wall formwork. The
usual method is to make up wall forms as framed panels with the plywood facing sheet screwed on to studs on
a timber frame. This allows for the plywood to be easily removed and reversed and used on both sides so as to
increase thenumber of reuses. The wall forms are susceptible to edge and corner damage and must be
carefully handled. Special attention must be given to comers and attached piers since the increased pressures
applied by wet concrete could cause the abutments to open up, giving rise to unacceptable grout escape and a
poor finish to the cast wall.
2.2 Need For Modern Formwork Systems
The earliest formwork systems made use of wooden scantlings and timber runners as it enabled easy forming
and making at site. But these wooden scantlings and timber runners tend to lose their structural and
dimensional properties over a period time and after repeated usage thus posing safety problems. Many of the
accidents take place in Reinforced Cement Concrete (RCC) construction because of inferior formwork and
scaffolding. Now focus has to be shifted to other key factor “Formwork”, to face the challenges for the
completion of fast track projects. By going in for system formwork, substantial savings are possible by faster
return on investments.
2.3 Plastics Used For Design Of Formwork
ABS (Acrylonitrile Butadiene Styrene)
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261 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
HIPS (High Impact Polystyrene)
HALENE PP
PP (Polypropylene)
2.4 Features And Limitations Of Plastic Formwork
The System is extremely light in weight as compared to wood and steel formwork system which requires
heavy lifting equipment’s.
Fast construction is achieved, and mainly suitable for large construction projects.
Locking system is very easy having nylon handles that lock with simple 90degree turn.
System components are durable and can be used several times without sacrificing the quality or
correctness of dimensions and surface.
Installation and dismantling is very easy and fast saving much more time.
System is extremely flexible as more number of combinations are possible.
Concrete does not stick to plastic which makes dismantling easy and less timing consuming.
System has extreme temperature tolerance of -30°C to 70°C.
System is fungus and termite resistance unlike traditional formworks hence improving life of formwork.
Cleaning is extremely easy. Just water is enough no requirement of any oil or lubricant.
2.5 Comparison Between Various Types Of Formwork
There are different types of formwork which are using for construction of building. But now a days
conventional formworks are not feasible to use according to cost, time and handling. Table below gives
comparison between various types of conventional formworks and modern formworks.
Table 1: Comparison between various types of formwork
Sr.
No Item
Wood
Formwork Steel Form Work
Plywood with Steel
formwork
Aluminium
Formwork
Plastic Formwork
(Geo-Plast)
01 Strength (kN/ Sq.m) 30 65 50 60 80
02 Difficulty Easy Difficult Average Easy Easy
03 Efficiency Low Quite High Average High
More than
aluminium
Formwork
04 Application
Wall, Column,
Beam, Slab,
Bridge.
Wall, Column,
Beam, Slab.
Wall, Column,
Beam, Slab, Bridge.
Wall, Column, Beam,
Slab.
Wall, Column,
Beam, Slab.
05 Recovery Value Rough Smooth Like Dry
Wall Smooth Finishing Smooth Finishing
Smoother finishing
than aluminium
Formwork
06 Maintenance Cost Low High Low Low Very Low
07 Durability Low Average Average High Very High
08 Life Span Short Long Long Long Used for 100 times
09 Speed of Construction Low Moderate Moderate High High
10 Labour Unskilled Semi-skilled Semi-skilled Skilled Semi-skilled
11 Recycle No Yes Yes/No Yes Yes
12 Self-Weight Light Heavy Heavy Light Light
13 Initial Cost Low High High High Moderate
14 Handling Average Difficult Difficult Easy Easy
Page 4
262 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
3. DESIGN OF MEMBERS
Design of different components of plastic formwork are discussed below.
Notation:
a= Weight of the formwork itself and the scaffold = Density x thickness of plate
b= Weight of fresh concrete (normal weight (heavy reinforced) X Thickness of slab
c= Uniform distributed load of runways for concrete transport and impact loads of the crowding of
crewmen(panel design)
d= Concentrated load form weight of work crews and transport equipment:= one crew member that carries
loads + wheel barrow/ buggies for concrete transport
q = uniformly distributed load pre unit length
σe = applied bending stress;
σa= allowable bending design stress;
M = bending moment [Nmm];
I = moment of inertia of the cross section [mm4];
W = section modulus of the cross- section [mm3].
h = Thickness of Plate [mm]
3.1 Slab Plate[3]
Sample calculations for Verification for Bending Stress.
The calculation is made for a width of b=1m.
𝑞 = 𝑎 + 𝑏 + 𝑐 × 1.00 + 𝑑 𝑙 ……(N/ m2)
For ABS type of plastic:
a = 10300.5 X 0.06 = 618.03 N/ m2
b= 25000 X 0.15 = 3750 N/ m2
c = 2500 N/ m2
d = 1300 + 2800 = 4100 N/ m2
𝑞 = 𝑎 + 𝑏 + 𝑐 × 1.00 + 𝑑 𝑙
q = (618.03 + 3750 + 2500) x 1.00 + 4100/0.252
q = 23137.87 N/m
Now, 𝜎𝑒 = 𝑀 𝑊 < 𝜎𝑎
Where, 𝑀 = 𝑞𝑙2 8
= 23137.87 X 0.2522 / 8
M = 183668.4 N-mm
𝑊 = 𝑏 × 2 6
= 1000 × 602 / 6
W= 6,00,000 mm3
𝜎𝑒 = 𝑀 𝑊 < 𝜎𝑎
= 183668.4 / 600000
𝜎𝑒= 0.3061N/ mm2<σa ………(σa= 70 N/mm
2)
Page 5
263 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
Table 2: Result of Critical Bending Stress
Sr. No. Composition of Plastic
Critical Bending Stress (MPa)
For
30 c.m. width Panel 60 c.m. width Panel
For Depth
(mm) Applied
Allowab
le
For Depth
(mm)) Applied Allowable
01 Halene PP M312 6 29.86 33 6 26.86 33
02 PP(Polypropylene Impact
Copolymer) 7033 6 29.86 37.65 6 26.86 37.65
03 ABS 4 67.15 70 4 60.40 70
04 HIPS 6 29.87 35 6 28.87 35
Sample calculations for Verification for deflection,
The calculation is made for a width of b=1m.
𝑞 = 𝑎 + 𝑏 × 1.00 + 𝑑 𝑙 …..(N/ m2)
For ABS type of plastic,
a = 10300.5 X 0.06 = 618.03 N/ m2
b= 25000 X 0.15 = 3750 N/ m2
q = (618.03 + 3750 ) x 1.00
q = 4.368 N/mm
For a rectangular beam subjected to bending the applied deflection can be calculated form the following
equation:
𝑓𝑒 = 5 384 × 𝑞 × 𝑙2 𝐸𝐼 < 𝑓𝑎
where, 𝐼 = 𝑏3 12 = 18 X 106 mm
4
E = 2600 MPa
fe= (5/ 384) X (4.368 x2524)/ 2600 X 18 X 10
6
fe= 0.00490 mm
fa = l / 300 = 0.84
𝒇𝒆 < 𝒇𝒂 …Hence OK.
Table 3: Result of Critical Deflection
Sr. No. Composition of Plastic
Critical Deflection (mm)
For
30 c.m. width Panel 60 c.m. width Panel
For Depth
(mm ) Applied
Allowabl
e
For Depth
(mm) Applied
Allowabl
e
01 Halene PP M312 15 0.724 0.84 14 0.889 0.92
02 PP(Polypropylene
Impact Copolymer) 7033 15 0.717 0.84 14 0.88 0.92
03 ABS 11 0.703 0.84 11 0.703 0.92
04 HIPS 13 0.743 0.84 10 0.894 0.92
Page 6
264 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
3.2Design of joist
Sample Calculations for Design of Joist for 1m
Notification:
a = Weight of the formwork itself
= Density × Plate Thickness
= 10300.5 × 0.015 = 154.5075 𝑁 𝑚2
b = Weight of fresh concrete (reinforced)
= 25000 × 0.15 = 3750 𝑁 𝑚2
c = Uniform distributed load of runways for concrete transport and impact loads of the crowding of
crewmen
= 1500 𝑁 𝑚2
𝑎 + 𝑏 + 𝑐 = 154.5075 + 3750 + 1500 = 5404.5075 [𝑁 𝑚2]
d = Concentrated load from weight of work crews and
transport equipment
= One crew member that carries load + wheel
barrow/buggies for concrete transport
=1300 + 2800
= 4100 N
l =𝑐/𝑐 distance between props = 0.2507 m
W= total UDL
𝑊 = 𝑞 = (𝑎 + 𝑏 + 𝑐) × 1 + (𝑑 ÷ 𝑙)
𝑊 = 5404.5075 + (4100/0.2507)
= 21804.5075 𝑁/𝑚
M = Maximum Bending moment
𝑀 =𝑤𝑙2
8 =
21804.50275
8 = 2725.56 𝑁𝑚
𝑀/𝐼 = Ϭ/𝑦
𝐼 = 𝑀𝑂𝑀𝐸𝑁𝑇 𝑂𝐹 𝐼𝑁𝐸𝑅𝑇𝐼𝐴 = 𝑑4/12
𝜎 = 𝑓𝑙𝑒𝑥𝑢𝑟𝑎𝑙 𝑠𝑡𝑟𝑒𝑠𝑠 = 70𝑀𝑃𝑎
𝑌 = 𝑒𝑥𝑡𝑟𝑒𝑚𝑒 𝑓𝑖𝑏𝑟𝑒 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑓𝑟𝑜𝑚 𝐶𝐺 = 𝑑/2
𝐸 = 𝑦𝑜𝑢𝑛𝑔’𝑠 𝑚𝑜𝑑𝑢𝑙𝑢𝑠 = 2600𝑀𝑃𝑎
𝑑3 = 2725.56 × 12
2 × 70 × 106
𝑏 = 𝑑 = 0.061588 𝑚
So, Joist is square in size, hence required size of joist should not be less than 𝟔. 𝟏𝟓𝟖𝟖 𝒄. 𝒎. 𝑿 𝟔.𝟏𝟓𝟖𝟖 𝒄. 𝒎.
Page 7
265 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
Table 4: Dimensions of Joist
3.3Design of Props [4]
Sample calculations for Design of Props
Name of plastic: ABS
𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 10300.5𝑁/𝑚3
𝑇𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 𝑝𝑙𝑎𝑡𝑒 = 0.015𝑚
𝑇𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 𝑠𝑙𝑎𝑏 = 0.15𝑚
DISCRIPTION
a = Weight of the formwork itself
= Density × Plate thickness
= 10300.5 × 0.015 = 154.5075𝑁/𝑚2
b = Wight of fresh concrete (reinforced)
= 25000 × 0.15 = 3750𝑁/𝑚2
c = uniform distributed load of runways for concrete transport and impact loads of the crowding of crewmen
= 1000𝑁/𝑚2
3.3.1 Design of Solid Props (for 3m)
𝑎 + 𝑏 + 𝑐 = 154.5075 + 3750 + 1000 = 4904.5075𝑁/𝑚2
𝑃𝑛 = (𝑎 + 𝑏 + 𝑐) × 𝑖𝑛𝑓𝑙𝑢𝑒𝑛𝑐𝑒 𝑎𝑟𝑒𝑎 = 4904.5075 × 0.3
𝑃𝑛 = 1471.35 𝑁
E = Flexural modulus.
𝑙𝑒 = 𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐿𝑒𝑛𝑔𝑡 = 0.7 × 3 = 2.1𝑚
𝑃𝑛 = 𝜋2𝐸𝐼 𝑙𝑒2
𝐼 = 𝜋 4 × 𝑑4
1471.3525 =𝜋3 4 × 2600 × 106 × 𝑑4
0.7 × 3 2
𝑑 = 23.82 𝑚𝑚
So, Diameter required should not be less than 𝟐𝟑. 𝟖𝟐 𝒎𝒎.
Types of plastic
Design values Actual values
Width
(cm)
Depth
(cm)
Width
(cm)
Depth
(cm)
ABS 6.154 6.154 10 5
HIPS 7.816 7.816 10 8
PP 7.673 7.673 10 8
HALEN PP 8.018 8.018 10 8
Page 8
266 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
Table 5: Dimensions of Solid Props
3.3.2 Design of Hallow Props (for 1.5m)
𝑊𝑒𝑖𝑔𝑡 𝑜𝑓 𝑠𝑜𝑙𝑖𝑑 = 𝜋 4 × 0.023822 × 3 × 10300.5
= 13.7710 𝑁
𝑎 + 𝑏 + 𝑐 = 154.5075 + 3750 + 1000 = 4904.5075𝑁/𝑚2
𝑃𝑛 = (𝑎 + 𝑏 + 𝑐) × 𝑖𝑛𝑓𝑙𝑢𝑒𝑛𝑐𝑒 𝑎𝑟𝑒𝑎 = 4904.5075 × 0.3
𝑃𝑛 = 1471.35 + 13.7710 = 1485.12 𝑁
E = Flexural modulus.
𝑙𝑒 = 𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐿𝑒𝑛𝑔𝑡 = 0.7 × 1.5 = 1.05 𝑚
𝑃𝑛 = 𝜋2𝐸𝐼 𝑙𝑒2
𝐼 = 𝜋 4 × 𝐷4 − 𝑑4
1485.12 =𝜋3 4 × 2600 × 106 × 𝐷4 − 𝑑4
0.7 × 3 2
𝑑 = 25.19 𝑚𝑚
So, Diameter required should not be less than 𝟐𝟓. 𝟏𝟗 𝒎𝒎
Table 6: Dimensions of Hallow Props
4. CONCLUSION
In traditional formwork system mainly wood and steel are being used as a material for formwork system. In
wooden formwork system, time delay and less accuracy are main constrained. Installation and dismantling
period is very high in wooden system. In steel formwork system accuracy is in work can be achieved but due
to its heavy weight it requires crane for lifting purpose as a result it proves to be time consuming. Also the
repetitions for wood and steel formwork have 10 and 60 repetitions respectively, while ABS plastic can be
used over 100 times. Due to its light weight ABS plastic formwork is easy to handle and easy to transport on
site, which increases labour productivity.
Type of
Plastic P E 𝑷 × 𝒍𝒆
𝟐 𝒅𝟒 d
ABS 1471.35 2.6E+09 6488.665 3.22E-07 0.023822
HIPS 1472.67 1.5E+09 6494.504 5.59E-07 0.027339
PP 1464.73 1.01E+09 6459.462 8.25E-07 0.03014
HALEN PP 1464.73 1E+09 6459.462 8.33E-07 0.030215
Type of Plastic P E 𝒅𝟒 𝑫𝟒 𝑫
ABS 1485.12 2.6E+09 3.22E-07 4.03E-07 0.0252
HIPS 1491.33 1.5E+09 5.59E-07 7.00E-07 0.02893
PP 1483.62 1.01E+09 8.25E-07 1.03E-06 0.031888
HALEN PP 1483.72 1E+09 8.33E-07 1.04E-06 0.031966
Page 9
267 Abhishek Balvir Patil, Akhilesh Anil More, Akshay Ashok Patil, Akshay Sunil Lohar,
Mikaj Shahajhan Sutar, Sayali Kiran Shirgave, Prof. Dr. G. M. Malu
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 4
April 2017
As deforestation is a major issue worldwide, these days use of ABS plastic as a alternative material for
formwork purpose might be possible solution against deforestation.
Thus it can concluded that the ABS plastic formwork technology is economical when used on large projects.
Increases Speed of construction. It enhanced labour productivity. Repetitions are much more than traditional
formwork techniques giving more than 100 repetitions and also ecofriendly alternative to wooden formwork
system as it is recyclable.
REFERENCES [1] Manual of TECHALTRA(2013), published by Ultratech, Vol.03, PP:02.
[2] Karke S. M. &Kumathekar M. B.(2002),“Comparison of the use of Traditional and Modern Formwork Systems”,
Civil Engineering Systems and Sustainable Innovations , Vol.04,PP:348-355.
[3] Octavian George Ilinoiu,Civil Engineering Dimensions, Vol. 8, No. 1, 47-54, March2006 (ISSN 1410-9530)
[4] Biggest Library of Free PDF and Product Manyal,CE 405: Design of Steel Structures, A. Varma