B.Tech Research Paper

DESIGN OF TRAVELLING FORMWORK

A project report submitted in partial fulfillment of the requirements for the award of degree of

Bachelor of Technology

in

Civil Engineering

Submitted by

PRABHA V.T. LAHARI (08131A0144)

K. TARAKESWARA RAO (08131A0125)

Under the guidance of

Dr. L VENKAT, PhD

Associate Professor, Civil Engineering

DEPARTMENT OF CIVIL ENGINEERING

GAYATRI VIDYA PARISHAD COLLEGE OF ENGINEERING

(AUTONOMOUS)

MADHURAWADA, VISAKHAPATNAM -530048

(Affiliated to JNT University, Kakinada, A.P)

April 2012

CERTIFICATE

This is to certify that the project report entitled “DESIGN OF TRAVELLING

FORMWORK FOR SEGMENTAL BOX-GIRDER” is the bonafide work carried during

the academic year 2011-2012 by

P.V.T. Lahari (08131A0144)

K. Tarakeswara Rao (08131A0125)

under the guidance of Dr. L.Venkat (PhD), Associate Professor, is submitted to the

Department of Civil Engineering, GAYATRI VIDYA PARISHAD College of Engineering

(Autonomous), Visakhapatnam in partial fulfillment of the requirements for the award of

degree of ‘Bachelor of Technology’ in ‘Civil Engineering’.

Project Guide HOD – Civil Engineering

…………………… .…………………..

Dr. L Venkat, PhD., Dr. Manchikanti Srinivas, M.Tech, Ph.D.,

Associate Professor, Professor, HOD,

Civil Engineering Dept. Civil Engineering Dept.

ACKNOWLEDGEMENTS

We wish to express our sincere grati tude to our project guide Dr. L Venkat,

Associate Professor, Department of Civil Engineering, for his esteemed

guidance for the successful completion of the project and for his constant

inspiration and encouragement.

We are thankful to Prof. N S V V S J Gandhi, Principal, G V P College of

Engineering and Dr. M Srinivas, Head of the Department, Department of

Civil Engineering for encouraging us to take up an innovative project and for

constant source of inspiration.

We thank our faculty and non-teaching staff of the department of Civil

Engineering for their constant support and assistance.

Prabha Venkata Tarunya Lahari

K Tarakeswara Rao

i

ABSTRACT

The safety, stability, speed and economy are the major concerns of any construction. As

formwork provides support and containment to the fresh concrete and provides the structure

with size and shape and controls its alignment and position, it forms an important part of the

construction. This project discusses the design of a steel formwork system for a box-girder

used in segmental bridge constructions which can be pre-fabricated and can be reused. This

approach is to increase the speed of the construction as well as the efficiency keeping

economic aspects under consideration. In order to comprehend the idea of the project more

effectively, study of design of concrete formwork for wall, column, slab, raft using timber and

steel has also been made and comparison of these models is also studied. A box girder

formwork system with mechanical screw jacks, bolted joints for haunch, rails, steel channels

and plates as its components, which can be reused for segmental bridge construction, has been

designed and design of each of its components is discussed. The design approach is such that

a single cell box girder formwork is first designed with the help of STAAD software

considering the different kinds of loads it is subjected to. The load calculations, the

calculations of the ultimate bending moment and the ultimate deflection under loads, on each

component are discussed along with the behavior of the formwork system under the loads it is

subjected to and different approaches for the design are studied. Advantages of this model are

also discussed.

ii

TABLE OF CONTENTS

ABSTRACT i

LIST OF FIGURES v

LIST OF TABLES vi

Page No.

CHAPTER-1 INTRODUCTION 1

1.1 Formwork 1

1.2 Formwork System 1

1.3 Objective and Scope of the Project 2

CHAPTER-2 FORM WORK 3

2.1 Design Considerations 4

2.2 Formwork for Concrete 5

2.3 construction of formwork 7

2.4 Order and method of removing formwork 7

2.5 Effect of Formwork on Concrete Quality 7

2.6 Causes of Formwork Failure 8

2.7 Planning for Formwork 8

CHAPTER-3 LOADS ON CONCRETE FORMWORK 9

3.1 Vertical Loads 9

3.2 Lateral Load 9

iii

CHAPTER-4 WALL FORMWORK 11

4.1 Wooden Formwork for Wall 11

4.2 Steel Formwork for Wall 13

CHAPTER-5 COLUMN FORMWORK 17

5.1 Wooden Formwork for Column 17

5.2 Steel Formwork for Column 20

CHAPTER-6 FORMWORK FOR RAFT FOUNDATION 23

6.1 Wooden Formwork for Raft Foundation 23

6.2 Steel Formwork for Raft Foundation 25

CHAPTER-7 SLAB FORMWORK 28

7.1 Wooden Formwork for Slab 28

7.2 Steel Formwork for Slab 30

CHAPTER-8 COMPARISON BETWEEN STEEL

AND WOODEN FORMWORK 35

8.1 Wooden Formwork 35

8.2 Steel formwork 36

8.3 Steel forms compared with wooden formwork 36

3.4 Timber Form Materials and Accessories 36

iv

CHAPTER-9 TRAVELLING FORMWORK

FOR BOX-GIRDER 40

9.1 Design Components 41

9.2 Load Calculation 42

9.3 Design Approach 43

9.4 Design of Travelling Formwork 45

9.5 Mechanical Screw Jacks 53

9.6 Rail Section 53

9.7 Hinge Connections 56

CHAPTER-10 CONCLUSION 57

REFERENCES 58

v

LIST OF FIGURES

FIG. NO TITLE Page No.

Fig. 1 Typical formwork setup for a wall 7

Fig. 2 Wall formwork 11

Fig. 3 Cross-section of a wall form 16

Fig. 4 Loading on column (plan view) 18

Fig. 5 Components of column form 22

Fig. 6 Raft foundation formwork 23

Fig. 7 Components of slab formwork 30

Fig. 8 Typical wall form with components identified 37

Fig. 9 Parts of typical wall form 37

Fig. 10 Different types of ties 38

Fig. 11 A continuous single member tie 39

Fig. 12 Typical cross-section of a box-girder bridge 40

Fig. 13 Dimensions of a single cell formwork 40

Fig. 14 Lateral pressure distribution 43

Fig. 15 Upper plate and strips 45

Fig. 16 STAAD drawing showing the reactions at supports for Upper plate 46

Fig. 17 Lateral plate and strips 48

Fig. 18 Loading on major beams 49

Fig. 19 Reactions at supports 50

Fig. 20 Dimensions of lateral plate 50

Fig. 21 Lateral plate with horizontal strips and major beams 51

Fig. 22 Mechanical Screw Jacks 53

Fig. 23 Loading on rail 54

Fig. 24 Section of a rail 54

Fig. 25 Components of formwork for box-girder 55

Fig. 26 Hinged Connections 56

vi

LIST OF TABLES

S. No TABLE NO. TITLE Page No.

1 1 Chemical coefficient Cc 10

2 2 Unit weight coefficient Cw 10

3 3 Allowable Stresses and Pressures

for Plywood Formwork 34

4 4 Normal size of members for wooden formwork 35

1

Chapter-1

INTRODUCTION

In the present world and ever since the beginning of the civilization, the purpose of any

construction is to provide the structure with maximum strength so that it can resist all kinds of

deformations effectively while it is also aesthetically sound, safe and is according to the plan

and within the constraints of the economy, environmental regulations and the welfare of the

general society.

Concrete reinforced buildings are preferred to other types of structures in most major

constructions because of the advantages they offer over structures made with other building

materials. Concrete has many advantages over the other building materials like its property of

being a durable material that reduces the building maintenance costs and provides a longer

service life. Reinforced concrete possesses considerable strength for resisting seismic and

wind loads. These factors and others make the selection of reinforced concrete an economical

alternative. The construction of a concrete building requires ‘formwork’ to support the slabs

(horizontal formwork) as well as columns and walls (vertical formwork).

1.1 Formwork

Formwork is defined as a temporary structure whose purpose is to provide support and

containment for fresh concrete until it can support itself. It molds concrete to the desired

shape and size, and controls its position and alignment.

Concrete forms are engineered structures that are required to support loads such as fresh

concrete, construction materials, equipment, workers, various impacts, and sometimes wind.

The forms must support all the applied loads without collapse or excessive deflection.

1.2 Formwork System

A formwork system is defined as “the total system of support for freshly placed concrete

including the mold or sheathing which contacts the concrete as well as supporting members,

hardware, and necessary bracing”.

Formwork provides support to the structure and is the largest component of the reinforced

concrete buildings and hence is the most important part of the construction of the structure, as

the safety of the structure depends on it. In the construction of formwork various methods

have been used based on the need and economy. Formwork cost accounts for 40 to 60 percent

2

of the cost of the concrete frame and for approximately 10 percent of the building cost. But

keeping the safety aspect in mind along with the economical aspects and the time factor, a

formwork has to be designed.

So far the formworks are built in place, used once and subsequently wrecked. With the

growing need to improve the quality of the structure with importance being given to the

economy and the time factor, the trend is to make use of the changing and ever-improving

technologies to make innovative developments in the design and construction of new types of

formworks that are pre-fabricated, assembled in large units, deployable and can be

continuously reused.

1.3 Objective and Scope of the Project

The main objective of our project hence, is to make use of technologies to design and develop

a travelling formwork of a segmental box-girder of a bridge that can be prefabricated,

assembled in large units, deployable and can be reused. The objective also includes the design

and analysis of various components of the box-girder under lateral loads, slab loads,

deflections etc., and to determine the failure that may occur due to various reasons and the

measures to be taken to prevent the failure. The design of steel and timber formworks for the

slab, wall, column and raft are also first discussed in order to better understand the formwork

system.

The design of such a formwork would improve safety, speed, and quality of the structure.

The aim of the project is to develop such a formwork for the box-girder that can be used in the

bridge construction which can further be developed for the design of other structures like

tunnels.

The box-girder designed is slightly different from the conventional box girders used for

bridges in that this box girder has bolted joints and vertical and horizontal hydraulic jacks to

reduce the size of the box both vertically and horizontally, after the casting is done so that it

can be moved from place to place and can be reused.

The formwork system and its various components and types of formwork like wood and steel

are first discussed in detail for slab, column, wall and raft before designing the travelling

formwork for box-girder. This is to understand better the formwork system so that a proper

design can be ensured.

3

Chapter-2

Formwork

Definition:

Any means or methods which provide temporary support, access, enhancement, or otherwise

facilitate the construction of permanent structures.

Necessity:

Temporary structures form the interface between design and construction. Most permanent

structures simply could not be built without temporary structures.

Impact on Schedule, Cost, and Quality

Losses in time and money will occur if the temporary structures are not planned and

coordinated with the same degree of thoroughness as the permanent structures.

A good formwork should satisfy the following requirements:

1. It should be strong enough to withstand all types of dead and live loads.

2. It should be rigidly constructed and efficiently propped and braced both horizontally

and vertically, so as to retain its shape.

3. The joints in the formwork should be tight against leakage of cement grout.

4. Construction of formwork should permit removal of various parts in desired sequences

without damage to the concrete.

5. The material of the formwork should be cheap, easily available and should be suitable

for reuse.

6. The formwork should be set accurately to the desired line and levels should have plane

surface.

2.1 Design Considerations

Safety

Designers must place the first priority on safety.IS codes, as well as other codes in the

industry, providing stringent performance specifications (how the system should work)

regarding temporary structures.

Formwork must be:

Strong to carry the full load and side pressure from freshly placed concrete, together

with construction traffic and equipment, and

Sound (made of good quality, durable materials)

4

Cost

Formwork can be the most expensive part of some construction projects. Designing cost-

effective solutions to temporary structures problems could easily be the competitive

advantage a contractor has over others. The designer must have a thorough knowledge of all

the options which will sufficiently solve the temporary structures problem.

Areas of cost reduction:

1. Planning for maximum reuse − A form designed for max reuse is stronger and more

expensive, but it can save on the total form cost.

2. Economical form construction

Use shop-built-forms− provides greatest efficiency in working conditions and in

The purchase and use of materials and tools;

Create shop area on the site− to form sections too large or transportation cost too high;

Use job-built− for small jobs, or where forms must be fitted to terrain;

Buy prefabricated forms(large number of reuses)

Rent prefab forms(better flexibility in regulating volume of work)

3. Setting and stripping

Repeat the same functions to increase the crew efficiency as the job progresses

Use metal clamp or special wedge pin connections that are secure, yet easy to

assemble and dismantle; and

Add extra features that make handling, erection, and stripping easier such as handles,

lifting eyes.

4. Cranes and Hoists

Size of form sections should be limited to the capacity of the largest crane planned for

the job.

Stair towers may be completed early in the schedule to be used for moving men and

materials.

Leave one bay open to permit mobile crane and concrete truck movement.

5. Bar Setting

Form design can permit the rebar to be pre-assembled before installation (more

favorable condition)

6. Concrete Placement

High lifts in wall construction make placing and vibration difficult.

Placing rate is limited by form design.

5

Unique Design Challenges

Temporary structures are subject to unique loading conditions which do not apply to a

permanent structure (fluctuating or dynamic loads, impact loads, and loads which change

position). Working within spatial constraints and cramped sites requires the most efficient

temporary structure so that workers still have room to maneuver safely.

It is always possible that an unforeseen condition could arise during an excavation due to

uncertainty of soil conditions. Designers must include an appropriate factor of safety in their

calculations or they may consider contingency plans for changing soil conditions.

Types of load that structures support are:

Dead loads – permanent; including self-weight, floor covering, suspended ceiling,

partitions, etc.

Live loads – not permanent; the location is not fixed; including furniture, equipment,

and occupants of buildings

Wind load (exerts a pressure or suction on the exterior of a building);

Other loads (hydrostatic pressure)

If the load is applied suddenly, the effects of IMPACT must be accounted for.

Design specifications provide guidance for the design of structural members and their

connections. They have no legal standing on their own, but they can easily be adopted, by

reference, as part of a building code. i.e., ACI 318-99- Building Code Requirements for

Structural Concrete. The Specifications for Design of Wood Members are by National Design

Specifications for Wood Construction by American Forest and Paper Association.

2.2 Formwork for Concrete

Formwork development has paralleled the growth of concrete construction throughout the

20th century. The increasing acceptance of concrete as a major construction material presents

the form builder a new range of problems in the development of appropriate sheathing

materials and maintenance of rigid tolerances. Figure 1 shows a typical concrete wall

formwork setup.

6

Fig. 1 - Typical wall formwork setup

Formwork is a classic temporary structure in the sense that it is erected quickly, highly loaded

for a few hours during the concrete placement, and within a few days disassembled for future

reuse. Also classic in their temporary nature are the connections, braces, tie anchorages, and

adjustment devices which forms need.

For concrete formworks, the notion of "Temporary Structures" does not quite portray the

reality. Forms, its hardware and accessories are used over and over again over their life time.

Because of that it is necessary to use materials with high durability and easy to maintain. The

form design should be such that it can be erected and disassembled efficiently in order to

maximize productivity. The disassembly or stripping of forms depends on factors such as the

bond between concrete and the form, rigidity and shrinkage of concrete. Since early form

removal is desirable for their reuse, a reliable basis for determining the earliest possible

stripping time is necessary.

Some of the early signs to look for during stripping are no excessive deflection or distortion

and no evidence of cracking or other damage to the concrete due to the removal of the forms

or the form supports. In any event, forms must not be stripped until the concrete has hardened

enough to hold its own weight and any other weight it may be carrying. The surface must be

hard enough to remain undamaged and unmarked when reasonable care is used in stripping

the forms.

7

Traditionally, formwork was erected in place and wrecked after only one time of usage. Due

to high labor costs, it is more efficient and profitable to prefabricate forms, assemble them in

large units using mechanical devices, such as cranes to erect the forms and reuse them as

much as possible.

Lumber was once the predominant form material, but developments in the use of plywood,

metal, plastics, and other materials, together with the increasing use of specialized

accessories, have changed the picture.

2.3 Construction of formwork:

This normally involves the following operations:

1. Propping and centering

2. Shuttering

3. Provision of camber

4. Cleaning and surface treatment

2.4 Order and method of removing formwork:

The sequence of orders and method of removal of formwork are as follows:

1. Shuttering forming the vertical faces of walls beams and column sides should be

removed first as they bear no load but only retain the concrete.

2. Shuttering forming soffit of slabs should be removed next.

3. Shuttering forming soffit of beams, girders or other heavily loaded shuttering should

be removed in the end.

Rapid hardening cement, warm weather and light loading conditions allow early removal of

formwork. The formwork should under no circumstances be allowed to be removed until all

the concrete reaches strength of at least twice the stresses to which the concrete may be

subjected at the time of removal of formwork. All formworks should be eased gradually and

carefully in order to prevent the load being suddenly transferred to concrete.

2.5 Effect of Formwork on Concrete Quality

In designing and building formwork, the designer should aim for maximum economy without

sacrificing quality or safety. Size, shape, and alignment of slabs, beams, and other concrete

structural elements depend on accurate construction of the forms.

The forms must be:

8

Sufficiently rigid under the construction loads to maintain the designed shape of the

concrete,

Stable and strong enough to maintain large members in alignment, and

Substantially constructed to withstand handling and reuse without losing their

dimensional integrity.

The formwork must remain in place until the concrete is strong enough to carry its own

weight, or the finished structure may be damaged.

2.6 Causes of Formwork Failure

Formwork failures are the cause of many accidents and building failures that occur during

concrete construction, usually when fresh concrete is being placed. Generally some

unexpected event causes one member to fail, then others become overloaded or misaligned

and the entire formwork structure collapses. The main causes of formwork failure are:

1. Improper stripping and shore removal

2. Inadequate bracing

3. Vibration

4. Unstable soil under mudsills (A plank, frame, or small footing on the ground used as a base

for a shore or post in formwork), shoring not plumb

5. Inadequate control of concrete placement

6. Lack of attention to formwork details.

2.7 Planning for Formwork

The engineer should plan for formwork at the time of making bid considering the following

factors:

Placing schedule and stripping time requirements;

Capacity of equipment available to handle form sections and materials;

Capacity of mixing and placing equipment;

Construction joints;

Reuse of forms as affected by stripping time;

Relative merits of job-built, shop-built and ready-made forms; and

Weather (protection requirements and stripping time)

9

Chapter-3

LOADS ON CONCRETE FORMWORK

3.1 Vertical loads:

Vertical loads consist of dead and live loads. The weight of formwork plus the weight of the

reinforcement and freshly placed concrete is dead load. The live load includes the weight of

the workers, equipment, material storage, runways, and impact.

Vertical loads assumed for shoring and reshoring design for multi-storey construction should

include all loads transmitted from the floors above as dictated by the proposed construction

schedule. The formwork should be designed for a live load of not less than 50 lb/ft2 (2.4kPa)

of horizontal projection. When motorized carts are used, the live load should not be less than

75 lb/ft2 (3.6kPa).The design load for combined dead and live loads should not be less than

100 lb/ft2 (4.8kPa) or 125 lb/ft2 (6.0kPa) if motorized carts are used.

3.2 Lateral load:

For concrete having a slump of 175 mm or less and placed with normal internal vibration to a

depth of 1.2 m or less, formwork can be designed for a lateral pressure as follows, where

Pmax = maximum lateral pressure, kPa;

R =rate of placement, m/h;

T = temperature of concrete during placing, °C;

Cw = unit weight coefficient per Table 3;

And

Cc = chemistry coefficient per Table 2;

For columns

With a minimum of 30Cw kPa, but in no case greater than ‘ρgh’.

For walls with a rate of placement of less than 2.1 m/h and a placement height not exceeding

4.2 m

With a minimum of 30Cw kPa, but in no case greater than ‘ρgh’.

10

For walls with a placement rate less than 2.1 m/h where placement height exceeds 4.2 m, and

for all walls with a placement rate of 2.1 to 4.5 m/h

With a minimum of 30CwkPa, but in no case greater than ‘ρgh’.

The chemistry coefficient Cc is determined from Table 1:

Table 1- Chemical coefficient Cc

Chemical coefficient Cc

Types I, II, and III without retarders* 1.0

Types I, II, and III with a retarder 1.2

Other types or blends containing less than

70% slag

or 40% fly ash without retarders*

1.2

Other types or blends containing less than

70% slag

or 40% fly ash with a retarder*

1.4

Blends containing more than 70% slag or

40% fly ash

1.4

The unit weight coefficient Cw is determined from Table 2:

Table 2 - Unit weight co-efficient Cw

Unit weight co-efficient Cw

Density of concrete Cw

Less than 2240 kg/m3

But not less than 0.8

2240 to 2400 kg/m3

1.0

Greater than 2400 kg/m3

*Retarders include any admixture, such as a retarder, retarding water reducer, retarding

midrange water-reducing admixture, or high-range water-reducing admixture (super

plasticizer), that delays setting of concrete.

11

Chapter-4

WALL FORMWORK

Load calculations:

Assumptions

Rate of placement of concrete (R) = 1 m/hr. < 2.1 m/hr.

Temperature of concrete during placing (T) = 270c

Height of the wall= 3 m.

We use OPC without retarders and assuming fresh concrete weight as 23 kg/m3

Hence cc= 1 and cw= 1.

Lateral loading on wall

……(1)

p= 24.84kN/m2< 30kN/m

2

Hence take p= 30 k/N/m2

(626psf)

Fig. 2 wall formwork

4.1 Wooden Formwork for Wall:

Ply wood:

Load on ply= 626psf (30kN/m2)

To find the support spacing for plywood sheathing, assume the sheets of plywood are oriented

in the form panel with the face grain across the supports (strong direction). Table 3 shows that

the plywood of thickness

will carry a pressure of 885psf (42.37kN/m

2) with supports

spacing of 8 in. This is also a convenient modular spacing for support of panel edges.

12

Wale spacing:

To determine wale spacing with 8” stud spacing, the load on each stud will be 535plf

(12.9kN/m). The studs must be supported by the wales so that the bending stress, the shear

stress, and the deflection in the studs do not exceed allowable levels.

If the studs have 3 or more spans, the maximum bending moment can be approximated from

the given formula.

.…(2)

Solving l gives,

.…. (3)

The allowable bending stress, Fb gives the allowable bending moment when multiplied by the

section modulus, S.

Use H16 timber beam which has bending capacity of 3kN-m.

Therefore L= 1.52 m.

But it should also satisfy the deflection criteria.

Hence

<

L<

L< 1.016

Therefore take least of 2 values. Hence provide 1m spacing between wales.

Tie spacing:

For wales, determine the spacing and size of tie required. Loads on wale are actually point

loads from studs but are often treated as distributed loads.

For 1 m wale spacing, the equivalent distributed wale load,

W = 1×30= 30kN/m.

Using Eq. 2,

Solving l gives,

Using Eq.3,

13


section modulus, Z.

35,200 mm3

Mallow= 0.66× fy ×Z …. (4)

Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

1.39 m

Deflection criteria:

L = 1.52 m

Therefore take least of 2 values. Hence provide 1350 mm spacing between ties.

Find the required tie size:

Load on tie = tie spacing ×wale load

= 1.35×30= 40.5kN.

The tie must have a safe working capacity of at least 41kN; the best choice is probably a 4.5

ton capacity tie.

4.2 Steel Formwork for Wall:

Load coming on to the wall = 30kN/m2

Use steel plate of thickness 3 mm.

Consider steel plate as beam of c/s dimensions 3 m×3 mm.

Then bending capacity Mallow= 0.66× fy ×Z

Therefore

= 4500 mm

3.

Using Eq. 4,

14

Mallow= 0.66×250×4500= 0.7425kN-m.

Using Eq. 3,


L = 182 mm

Therefore take least of 2 values. Hence provide 180 mm spacing between studs.

If the studs have 3 or more spans, the maximum bending moment,

Solving l gives,


section modulus, Z.

2083.33 mm3

Using Eq. 4,

Mallow= 0.66× fy ×Z.

Mallow= 0.66×250×2083.333= 0.34kN-m.

Therefore

15

0.79 m


L = 0.9 m

Therefore take least of 2 values. Hence provide 790 mm spacing between wales.



For 0.79 m wale spacing, the equivalent distributed wale load,

W= 0.79×30 = 23.7kN/m.

Using Eq. 3,

Solving l gives,


section modulus, Z.

35,200 mm3

Using Eq. 4,


Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

1.5 m

16


L = 1.6 m



Load on tie = tie spacing × wale load = 1.5×23.7= 35.55kN.

The tie must have a safe working capacity of at least 36kN; the best choice is probably a 4 ton

capacity tie. The wall form c/s is shown in Figure 2.

Fig. 3 Cross-section of Timber Wall Form

17

Chapter-5

COLUMN FORMWORK

Load calculations:

Assumptions

Rate of placement of concrete (R) = 1 m/hr. < 2.1 m/hr.

Temperature of concrete during placing (T) = 270.

Column dimensions 400 mm×400 mm.

We use OPC without retarders and assuming fresh concrete weight as 23 kg/m3

Hence cc= 1 and cw = 1.

Lateral loading on column

From Eq. 1

….. (1)

p = 24.84kN/m2< 30kN/m

2

Hence take p= 30 k/N/m2

5.1 Wooden Formwork for Column:




will carry a pressure of 885psf (42.37kN/m2) with supports

spacing of 8 in. This is also a convenient modular spacing for support of panel edges. The

loading on column form is shown in Figure 3.

18

Fig. 4 Loading on Column (plan view)

Wale spacing:

To determine wale spacing, with 8” stud spacing, the load on each stud will be 417plf

(9.1kN/m)

If the studs have 3 or more spans, the maximum bending moment can be approximated.

Using Eq. 2,

Solving l gives,


section modulus, S.


19

Therefore L = 1.81 m for given loading of


Hence

<

L<

L< 1.1

Therefore take least of 2 values. Hence provide 1.1 m spacing between wales.




W = 1.1×30 = 33kN/m.

Using Eq. 2,


section modulus, Z.

Using Eq. 4,


Mallow= 0.66×250×4,200= 0.693kN-m > 0.45kN-m


Provide ISA5030 for wales.

Load on each bolt at the end of wale = 6.6k.

20

5.2 Steel Formwork for Column:

Loading on plate:

Using Eq. 4,

Bending capacity of t mm thick plate = 0.66× fy ×Z

= 0.66×250×

= 27500× t2

N-mm.

But it should be greater than max.bending moment,

27500× t2> 0.15×10

6

t > 2.33mm


t > 3.001

Therefore‘t’ should be greater than 3 mm.

Hence take 3 mm plate.

For 0.2 m spacing load coming on to studs = 30×0.2 = 6kN/m.


Solving l gives,

21


section modulus, Z.

2083.33 mm3

Using Eq. 4,


Mallow= 0.66×250×2083.333= 0.34kN-m.

Therefore

0.75 m


L = 0.88 m





W = 0.75×30= 22.5kN/m.


section modulus, Z.

22

Using Eq. 4,


Mallow= 0.66×250×3,400= 0.56kN-m > 0.45kN-m


Provide ISA5030 for wales.

Load on each bolt at the end of wale = 4.5kN

Fig. 5 components of column form

23

Chapter-6

FORMWORK FOR RAFT FOUNDATION

6.1 Wooden Formwork for Raft Foundation:



the plywood will carry a pressure of 885psf (42.37kN/m2) with supports spacing of 8 in. This

is also a convenient modular spacing for support of panel edges.

Fig.6 raft foundation formwork

Wale spacing:

To determine the wale spacing: With an 8 in. stud spacing, the load on each stud will be

417plf (9.13kN/m2). The studs must be supported by the wales so that the bending stress, the

shear stress, and the deflection in the studs do not exceed allowable levels.


the given Table 3,

Using Eq. 2,

Solving l gives,


section modulus, S.

24


Therefore L=1.52 m.


Hence

<

L<

L< 1.016

Therefore take least of 2 values. Hence provide 1m spacing between wales.




W = 1×30= 30kN/m.

Using Eq. 2,

Solving l gives,


section modulus, Z.

35,200 mm3

Using Eq. 4,


Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

1.39 m


25

L = 1.52 m




= 1.35×30= 40.5kN.

The tie must have a safe working capacity of at least 41kN; the best choice is probably 4.5

ton tie.

6.2 Steel Formwork for Raft Foundation:

Load coming on to the wall = 30kN/m2

Use steel plate of thickness 3 mm.


Then bending capacity Mallow= 0.66× fy ×Z.

Therefore

= 1500 mm

3.

Using Eq. 4,

Mallow= 0.66×250×1500= 0.2475 kN-m.

Using Eq. 3,


26

L = 182 mm


Load on studs= 0.18×30= 5.4kN/m2.


Solving l gives,


section modulus, Z.

2083.33 mm3

Using Eq. 4,


Mallow= 0.66×250×2083.333= 0.34kN-m.

Therefore

0.79 m


L = 0.9 m





W = 0.79×30 = 23.7kN/m.

27

Using Eq. 2,

Solving l gives,


section modulus, Z.

35,200 mm3

Using Eq. 4,


Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

1.5 m


L = 1.6m




= 1.5×23.7= 35.55kN.

The tie must have a safe working capacity of at least 36kN; the best choice is probably 4 ton

capacity tie.

28

Chapter-7

SLAB FORMWORK

Load calculations:

Loading on slab:

Fresh concrete load of slab thickness 150 mm= 25×0.15 (including reinforcement)

= 3.75kN/m2.

Live load on slab according to ACI 347 = 3.6kN/m2

Total load= 7.37kN/m2

Factored load= 12kN/m2 (250psf)

7.1 Wooden Formwork for Slab:

Loading on slab:

Fresh concrete load of slab thickness 150mm = 25×0.15 (including reinforcement)

= 3.75kN/m2.

Live load on slab according to ACI 347 = 3.6kN/m2

Total load= 7.37kN/m2

Factored load= 12kN/m2 (250psf)




will carry a pressure of 265psf (12.68kN/m2) with supports

spacing of 16 in. This is also a convenient modular spacing for support of panel edges

Wale spacing:

With 16” stud spacing, the load on each stud will be 334plf (4.872kN/m)


the given Table 4,

Using Eq. 2,

Solving l gives,

29


section modulus, S.


Therefore L=2.48 m.


Hence

<

L<

L< 1.11

Therefore take least of 2 values. Hence provide 1.1 m spacing between wales.




W = 1.1×12= 13.2kN/m (832plf)

Using Eq. 2,

Solving l gives,


section modulus, Z.

35,200 mm3

Using Eq. 4,

Mallow= 0.66× fy ×Z

Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

2.09m

30


L = 1.52 m

Therefore take least of 2 values. Hence provide 1500 mm spacing between posts.

Finding the required post size:

Load on post = post spacing ×wale load

= 1.5×13.2= 19.8kN.

Assuming fcd= 75 N/mm2

Area required = 19.8×103/75 = 264 mm

2

Use 3.2 mm thick pipe,

External diameter of pipe = 33.7 mm.

Area provided= 306 mm2

Moment of inertia= 36100 mm4

Radius of gyration =

= 10.8 mm

89.1388.10

15001

r

KL

From the Table 9.1(a) in IS800-2007

fcd = 82 N/mm2

Load carrying capacity of post = 306×81.6= 25kN>19.8kN

Therefore, post of Ø33.7 mm with 3.3 mm thick is satisfying all the requirements.

Fig. 7 components of slab form (timber)

31

7.2 Steel Formwork for Slab:

Load on plate = 12kN/m2


Using Eq. 4,

Then bending capacity Mallow= 0.66× fy ×Z.

Therefore

= 1500 mm

3.

Using Eq. 4,

Mallow= 0.66×250×1500= 0.2475kN-m.

Using Eq. 3,


L = 240 mm


Load on studs= 0.24×12= 2.88kN/m2.


Using Eq. 2,

Solving l gives,


section modulus, Z.

32

2083.33 mm3

Using Eq. 4,


Mallow= 0.66×250×2083.333= 0.34 kN-m.

Therefore

1.08m


L = 1.13 m

Therefore take least of 2 values. Hence provide 1 m spacing between wales.




W = 1×12= 12kN/m.

Using Eq. 2,

Solving l gives,


section modulus, Z.

35,200 mm3

Using Eq. 4,


33

Mallow= 0.66×250×35,200= 5.8kN-m.

Therefore

2.2 m


L = 2.23 m

Therefore take least of 2 values. Hence provide 2.2 m spacing between posts.

Post design:

Load coming on to each pole = 2.2×9.48= 21.1kN.

Assuming fcd= 90 N/mm2

Area required = 21.1×103/75= 293.33 mm

2

Use 3.2 mm thick pipe,

External diameter of pipe = 33.7 mm.

Area provided= 306 mm2

Moment of inertia= 36100 mm4

Radius of gyration =

= 10.8 mm

89.1388.10

15001

r

KL

From the Table9.1 (a) in IS800-2007

fcd = 82 N/mm2

Load carrying capacity of post = 306×81.6= 25kN> 21.1.

Therefore, post of Ø33.7 mm with 3.3 mm thick is satisfying all the requirements.

34

Table 3– Allowable Stresses and Pressures for Plywood Formwork

Allowable Stresses and Pressures for Plywood Formwork

35

Chapter-8

COMPARISON BETWEEN STEEL AND WOODEN

FORMWORK

Timber is the most common material used for formwork. The disadvantage with timber

formwork is that it will warp, swell and shrink. Application of water impermeable cost to the

surface of wood mitigates these defects.

The construction of formwork takes time and involves expenditure up to 20 to 25% of the

cost of the structure or even more. Design of these temporary structures is made to economic

expenditure. 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 are called

stationary forms.

8.1 Wooden Formwork:

Timber for formwork should satisfy the following requirement:

It should be

1. well-seasoned

2. light in weight

3. easily workable with nails without splitting

4. free from loose knots

Normal sizes of members for timber formwork are shown in Table 1:

Table 4 - Normal size of members for wooden formwork

Sheeting for slabs, beam, column

side and beam bottom

25 mm to 40 mm thick

Joints, ledges 50 x 70 mm to 50 x 150 mm

Posts 75 x 100 mm to 100 x 100 mm

36

Resin bonded plywood sheets are attached to timber frames to make up panels of required

sizes. The cost of plywood formwork compares favorably with that of timber shuttering and it

may even prove cheaper in certain cases in view of the following considerations:

1. It is possible to have smooth finish in which case on cost in surface finishing is there.

2. By use of large size panels it is possible to effect saving in the labor cost of fixing and

dismantling.

3. Numbers of reuses are more as compared with timber shuttering. For estimation

purpose, number of reuses can be taken as 20 to 25.

8.2 Steel Formwork

This consists of panels fabricated out of thin steel plates stiffened along the edges by small

steel angles. The panel units can be held together through the use of suitable clamps or bolts

and nuts. The panels can be fabricated in large number in any desired modular shape or size.

Steel forms are largely used in large projects or in situation where large number reuses of the

shuttering is possible. This type of shuttering is considered most suitable for circular or

curved structures.

8.3 Steel forms compared with wooden formwork:

1. Steel forms are stronger, durable and have longer life than wooden formwork and their

reuses are more in number.

2. Steel forms can be installed and dismantled with greater ease and speed.

3. The quality of exposed concrete surface by using steel forms is good and such surfaces

need no further treatment.

4. Steel formwork does not absorb moisture from concrete.

5. Steel formwork does not shrink or warp.

8.4 Timber Form Materials and Accessories

Practically all formwork jobs require some lumber. A local supplier will advise what material

and sizes are in stock or promptly obtainable, and the designer or builder can proceed

accordingly. Figure 5 shows a typical wall form with its components. Figure 6 shows parts of

a typical wall form.

37

Fig. 8 - Typical wall form with components identified.

Fig. 9 - Parts of a typical wall form

38

Ties

In order to secure concrete forms against the lateral pressure of unhardened concrete, a

tensile unit called concrete form tie is used (they are also referred to as form clamps, coil ties,

rod clamps, snap ties, etc.). Figure 7 shows a typical single member tie.

Fig.10 Different types of ties

Ties are manufactured in two basic types:

Continuous single member ties; in which the tensile unit is a single piece, have a

special holding device added for engaging the tensile unit against the exterior of the -

form shown in Figure 5. Some single member ties may be pulled as an entire unit from

the concrete; others are broken back a predetermined distance. Some are cut flush with

the concrete surface.

39

a) Straight tie with elastic tube

b) Threaded bar with unattached plastic sleeve

Fig. 11 – A continuous single member tie

Internal disconnecting type ties, in which the tensile unit has an inner part with

threaded connections to removable external members generally, remain in the

concrete.

40

Chapter-9

TRAVELLING FORMWORK FOR BOX-GIRDER

The travelling formwork for one cell of a twin cell segmental box girder is considered for

design.

The dimensions of the formwork under consideration are shown in the Figure 8.

Fig. 12 Typical Cross-section of Box-girder Bridge

Single cell for which the travelling formwork is designed is as shown in the Figure 9.

Fig. 13. Dimensions of the single cell formwork

41

9.1 Design Components

Upper Steel Plate/ Slab: An upper steel plate is provided to bear the external loads and acts as

a slab to the whole system.

Lateral/Vertical Steel Plates: Lateral plates of steel are provided to resist the lateral loading

and to provide a shape in the form of walls to the system.

Strips: Vertical and Horizontal Strips are provided as supports to the upper and lateral plates

which are in turn supported by the major beams of ISMC 75 Back to back channels. Lateral

buckling of these members is possible due to their lesser depth and more width compared to

depth and hence strips at regular intervals are to be provided to prevent buckling.

Back to back ISMC75 Channels: Back to back ISMC75 channels are provided to resist the

torsion and to provide support to the slab, there is a gap provided between the back to back

channels to enable future enhancements.

Horizontal Mechanical Jack: One horizontal hydraulic jack is provided to facilitate the

movement of the slab formwork in the horizontal direction.

Vertical Mechanical Jack: Two vertical hydraulic jacks are provided based on the length of

the formwork. These facilitate the movement of the walls of the box girder in upward and

downward directions to the restricted lengths.

Hinged Connection: Hinged connections are provided at the two upper corners of the box i.e.,

for the haunch so that when the box has to be compressed for reuse, after the casting is done,

the corners can be folded.

Rails: Rails are provided at the bottom end of each vertical jack so that the formwork can be

moved forward or backward to the desired position for reuse.

The design of each and every component should be done with great care and based on the

standard specification codes. The length and number of the hydraulic jacks and the design of

bolts and rails also depends on the requirement criteria.

42

9.2 Load Calculation:

Loading ( On Upper plate/ slab):

Weight of fresh concrete = density× thickness

= 25×0.4 = 10kN/sq.m

Weight of plate (6 mm thick) =78.5×0.006

=0.471kN/sq.m

Hence, Live load = 75psf

= 75×0.04788kN/sq.m

= 3.591kN/sq.m

And total vertical load = 10 + 0.471 +3.591

= 14.062

= 15kN/sq.m (approx.)

Therefore, factored vertical load = 15×1.5 = 22.5kN/sq.m

Lateral load ( On vertical/lateral plates):

Assuming, Rate of pouring (R) = 1 m/hr

= 3.281 ft/hr

Temperature (T) = 27oC

= 27 + 273= 300 K

According to ACI 347,

Lateral Pressure,

T

Rp 9000150

300

281.39000150

43

= 248.43 psf = 11.89kN/sq.m

Factored load = 11.89×1.5 = 17.835kN/sq.m

Therefore, the envelope of the maximum pressure will show a hydrostatic pressure at a depth

below the form 150

43.248 = 1.66 ft = 0.5 m

Hence, from the above calculation, till the depth of 0.5m the pressure distribution will be

linear, then it will be constant.

{1psf= 0.0478803kN/sq.m = 0.0208854 lb/sq.ft}

The envelope of lateral pressure distribution is shown in Figure 10:

Fig.14 Lateral Pressure Distribution

9.3 Design Approach

In order to design the components of the formwork, STAAD software is used. The upper

plate, lateral plates, beams (horizontal, central and cross members) are designed on STAAD

for the loads calculated as shown above and the results obtained for Bending Moments and

Deflections are compared with the calculated allowable stress and deflection. The number of

bays, number of members, the distance between each member is based on these values. The

suitable combination of the number of bays and the deflection and bending moment obtained

44

which are less than the allowable deflection and bending moment values respectively are

considered for the final design.

For example, for the upper plate design allowable bending moment value obtained from

calculations is 1.485kN-m and the allowable deflection value is 0.6944m. Then, for a vertical

load of 33.75kN/m (calculated) and thickness of the plate- 0.006m, length- 2m as fed in

STAAD, if we take 9 supports i.e., 8 bays (bay distance of 0.25m), the maximum deflection

obtained is 0.151m which exceeds allowable deflection and the maximum bending moment

value obtained is 0.223kN-m which is within the allowable limit. But as the deflection criteria

is not satisfied and hence not safe, we go for another number of bays like 5 or 6 bays

whichever satisfies the allowable deflection and the allowable bending moment criterion.

Calculation of Allowable Deflection and Allowable Bending Moment:

Allowable deflection limit =360

span

Allowable Bending Stress = Z

Mf

Allowable Bending Moment = M = f ×Z

6250

3

2 dbd [‘f’ value for Mild steel

is 250 N/ sq.mm]

The obtained maximum bending moment and deflection values for all the components should

be within these limits.

45

9.4 Design of Travelling Formwork:

The design of various components of a travelling formwork mentioned in Chapter 7 is

discussed further. The upper plate is shown in Figure 11.

Fig.15 Upper plate and strips

Upper Plate/ Slab ( 6 bays and 7 supports including ends):

Thickness= 6 mm

Bay length= 0.333 m

Width= 1.5 m

Length= 2 m

From the above load calculation, vertical load on the plate= 22.5× width of the plate,

Vertical Load = 22.5× 1.5= 33.75kN/m

Allowable deflection= 250/360= 0.6944 mm

Allowable Bending Moment

6

66150025066.0 = 1.485kN-m

STAAD RESULTS:

Max. Deflection= 0.475 m < 0.6944 mm

46

Max. Bending moment= 0.396kN-m <1.485kN-m

Hence Safe.

Sometimes, even though the max.deflection and the max.bending moment obtained are within

the allowable limits, the design might not be considered if obtained max.deflection or bending

moments are too less than the allowable limits. Even if the values are appropriate the number

of bays could be very high, which is not economical. In these cases, combinations have to be

changed.

STAAD drawing showing the reactions at supports for Upper plate are shown in Figure 12:

Fig.16 STAAD drawing showing the reactions at supports for Upper plate.

Vertical Strips( 7 nos):

Vertical End Strips:

Depth= 6 cm

Width= 6 mm

Length= 1.5 m

For end strips, Loading= 22.5×0.33/2= 3.7125kN/m

47

Allowable deflection= 360

l =

360

10008.0 = 2.22 mm

For Overhang portion, allowable deflection= 360

100035.0 = 0.97 mm

Allowable Bending Moment=

6

5050625066.0 = 0.41kN-m

STAAD RESULTS:

Max. deflection= 0.944 m < 2.22 mm

< 0.97 mm

Max. Bending moment= 0.24kN-m <0.41kN-m

Hence safe.

For Vertical end strips, depth of 6 mm and width of 6 cm are used and as shown above, it

satisfies the deflection and bending moment conditions.

But for the Vertical Intermediate strips, if same depth and bending moment are used and the

loading on them is twice than that of the Vertical End strips and in that case, the deflection

and Bending moment obtained are very high and exceed the allowable deflection and bending

moment.

So, depth, as it cannot be changed, we increase the width to 8 mm for Vertical Intermediate

strips to reduce the bending moment and deflection.

Vertical Intermediate Strips:

Depth= 6 cm

48

Width= 8 mm

For Central strips, Loading= 22.5×0.33= 7.425kN/m

Allowable Deflection= 360

l

360

100035.0 = 0.9777 mm

STAAD RESULTS:

Max. deflection= 0.772 mm< 0.9777 mm

Max. Bending moment= 0.46kN-m

Hence safe.

As the allowable deflection for overhang part (of length 0.35 mm) is more than that of the part

between supports (i.e., of length 0.8 mm), the obtained deflections can be compared for all the

parts with the allowable deflection of the overhanging part.

Major Beams (B/B ISMC 75 OF 2 nos):

To support the vertical members which are supports for slab, two major beams of back to

back ISMC 75 are provided. These are shown in the Figure 13:

Fig.17 Lateral Plate and Strips

The vertical members act as point loads on the two major beams as shown in Figure 14:

49

Fig.18 Loading on Major Beams

The vertical members act as point loads on the two cross members as shown above.

Length= 2 m

ISMC 75 channels section details:

Allowable deflection= 360

250=

360

)333.022( = 3.7 mm

50


1000

22.2025066.0 = 6.666kN-m

STAAD RESULTS:

Max. deflection= 3.594 m < 3.7 mm

Max. Bending moment= 5.96kN-m < 6.666kN-m

Hence safe.

The reactions at supports are shown in Figure 15.

Fig.19 Reactions at Supports

Lateral/Vertical Plates:

Lateral plate is shown in Figure 16:

Fig.20 Dimensions of Lateral Plate

51

Thickness= 6 mm

Width= 2 m

Loading= 18×2 m= 36kN/m

6 Supports:

Allowable deflection = 360

10004.0 = 1.11 mm


6

661000225066.0 = 1.98kN-m

STAAD RESULTS:


Max. Bending moment= 0.61kN-m< 1.98kN-m

Hence Safe.

Horizontal Strips:

The horizontal strips and major beams are shown in Figure 17:

Fig.21 Lateral Plate with Horizontal Strips and Major Beams

52

Horizontal End Strips:

Allowable deflection=

300300

101010445.0 = 1.236 mm


6

6060525066.0 = 0.495kN-m


Max. Bending Moment= 0.305kN-m

Reactions on major beam= 3.6kN, 3.6kN

Horizontal Intermediate Strips:


360

101010445.0 = 1.230 mm


6

8080525066.0 = 0.85kN-m

Max. deflection= 0.726 mm

Max. Bending moment= 0.713kN-m

Reaction= 7.2kN, 7.2kN

Major Beams (B/B ISMC 75 of 2 nos):

The section details for the major beams are same as that of the major beams for the upper

plate.

Z (w.r.t X-axis)= 20.2 cu.m for single columns

Moment Capacity= )101010(2.2025066.0 = 6.666kN-m

Max. Moment= 1.44kN-m

Max.deflection= 0.673 mm


300

101010400 = 1.11kN-m

53

Reactions:

At A= 18kN, At B= 18kN

9.5 Mechanical Screw Jacks:

Vertical Jacks:

4 Mechanical screw jacks of 4 tons capacity are used as the load coming on each one is 3.6

tons.

Horizontal Jacks:

4 mechanical screw jacks of 2 tons capacity are used as the load coming on each one is 1.8

tons.

These will be clamped to the major beams of the slab and the lateral plate.

The mechanical screw jacks that can be used are shown in Figure 18:

Fig.22 Mechanical Screw Jacks

9.6 Rail Section:

Rails are used to facilitate the movement or transfer of the formwork from one segment to the

next after the concrete is set.

The loading on the rail and the bending capacity are shown in Figure 19:

54

Fig. 23 Loading on Rail

Max BM = 11.25kN-m

Bending capacity = 12.6kN-m

Section of the rail that is used in the formwork floor is as shown in the Figure 20:

Fig.24 Section of a Rail

55

A drawing of the cross section of the box girder with the above described components is

shown in the Figure 21. The hinged connection at the haunch is showed in detail in Figure 22.

Fig.25 Components of Formwork for Box-girder

56

9.7 Hinge Connections:

Hinges are provided for haunch as the connections between the ends of upper slab and the

lateral plates to enable the folding of the formwork for reuse.

The hinged connections that are used for this purpose are as shown in the Figure 22:

Fig.26 Hinged Connections

57

Chapter-10

CONCLUSION

The summary report presented above discusses the design aspects of a travelling formwork

for a segmental box girder which can be prefabricated and reused. Prior to this the design of

steel and timber formworks for slab, raft, column and wall are also discussed in order to

understand the project better. A comparison between steel and wood formworks is discussed

along with the temporary structures. As the economy, speed and efficiency are the major

considerations of any project, an effort has been made to improve the efficiency of the project

by reducing the waste of time and material by designing a travelling formwork for a

segmental box girder. This formwork can be reused for one segment after another after the

concrete is set. This prefabricated formwork design and its components are discussed in the

report. The detailed design of each component using STAAD PRO software and the

calculations based on references and IS codes are presented. The model can be reused and

hence it is advantageous over various other formwork systems as it improves the work

efficiency by reducing the time taken for construction and wastage of material.

58

REFERENCES

1) Arch Alexander, “Design and Construction of Concrete Formwork”, The Civil

Engineering Handbook, Second Edition, Edited by W . F . Chen and J . Y . Richard

Liew, CRC Press 2002, Chapter-4.

2) Brand, R.E. 1975. Falsework and Access Scaffolds in Tubular Steel. McGraw-Hill,

New York.

3) Chen, W.F. and Mosallam, K.H. 1991. Concrete Buildings, Analysis for Safe

Construction. CRC Press, BocaRaton, FL.

4) Hurd, M.K. 1989. Formwork for Concrete, 6th ed. American Concrete Institute,

Detroit, MI.

5) Moore, C.E. 1977. Concrete Form Construction. Van Nostrand Reinhold, New York.

6) Peurifoy, P.E. 1976. Formwork for Concrete Structures. McGraw-Hill, New York.

7) Ratay, R.T. 1984. Handbook of Temporary Structures in Construction. McGraw-Hill,

New York.

8) Load calculations including vertical and lateral were based on ACI Committee 347

recommendations.

9) IS: 14687- 1999 Falsework for the Concrete Structures-Guidelines.

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