national training materials construction studies

NATIONAL TRAINING MATERIALS

CONSTRUCTION STUDIES

AUSTRALIAN

NATIONAL TRAINING

AUTHORITY

CCC348 - FORMWORK:SUSPENDED

DEVELOPED IN COLLABORATION BETWEEN INDUSTRY AND TAFE QUEENSLAND WITH THE

SUPPORT OF THE AUSTRALIAN NATIONAL TRAINING AUTHORITY

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ACKNOWLEDGEMENTSProduced by the Construction Curriculum Consortium, TAFE Queensland.

Managing Agent : Recognition Directorate, Vocational Education, Training AndEmployment Commission (VETEC)

© Australian National Training Authority (ANTA) 1997

All rights reserved. This work has been produced initially with the assistance of funding provided by theCommonwealth Government through ANTA. This work is copyright, but permission is given to trainersand teachers to make copies by photocopying or other duplicating processes for use within their owntraining organisation or in a workplace where the training is being conducted. This permission does notextend to the making of copies for use outside the immediate training environment for which they aremade, nor the making of copies for hire or resale to third parties. For permission outside theseguidelines, apply in writing to Australian Training Products Ltd.(formerly ACTRAC Products Ltd).

The views expressed in this version of the work do not necessarily represent the views of ANTA. ANTAdoes not give warranty nor accept any liability in relation to the content of this work.

Published by Australian Training Products Pty (formerly ACTRAC Products Ltd),Australian National Training Authority.GPO Box 5347BB, MELBOURNE, Victoria 3001, AustraliaTelephone +61 03 9630 9836 or 9630 9837;Facsimile +61 03 9639 4684

First Published October 1997

DP2120348LRG

Printed by Document Printing Australia

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NATIONAL CONSTRUCTION STUDIES

RESOURCE PROJECT

STAGE 3

FIELD OF WORK SKILLS

LEARNING PACKAGE

CCC348 - FORMWORK: SUSPENDEDSLAB AND BEAM

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PUBLISHED: 1997

ACKNOWLEDGMENTS:

AUTHOR:

Holmesglen Institute of TAFEBatesfsford RoadCHADSTONE, Victoria

INSTRUCTIONAL DESIGNER:

Construction Curriculum ConsortiumTAFE Queensland

This learning package was developed as part of the AVTS Training Program in Construction Studies

This project was managed by the Construction Curriculum Consortium, TAFE Queensland

For further details contact:

Noel RyanManagerConstruction Curriculum ConsortiumYeronga Institute of TAFEPO Box 6045FAIRFIELD GARDENS QLD 4103

Telephone: (07) 3892 0457Facsimile: (07) 3892 0457

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TABLE OF CONTENTS

Page

INTRODUCTION ..................................................................................................................... 11

OVERVIEW............................................................................................................................... 14

WHAT IS PROVIDED ............................................................................................................. 15

WHAT YOU PROVIDE?......................................................................................................... 15

HOW TO USE THIS PACKAGE ........................................................................................... 16

GETTING TO “KNOW THE PACKAGE”.......................................................................... 17KEY TO SYMBOLS .............................................................................................................. 18

MODULE INFORMATION: FROM THE TRAINING SPECIFICATION................... 19

ASSESSMENT INFORMATION............................................................................................ 21

ASSESSMENT SPECIFICATION.......................................................................................... 22

ASSESSMENT TASKS............................................................................................................. 24

ASSESSMENT TASK 1:........................................................................................................ 24ASSESSMENT TASK 2:........................................................................................................ 26

SECTION 1 - THE PRINCIPLES OF FORMWORK DESIGN, PLANNING ANDQUALITY CONTROL ............................................................................................................. 27

INTRODUCTION...................................................................................................................271. FORMWORK MEMBER SIZES AND SPACINGS........................................................ 282. FALSEWORK MEMBER SIZES AND SPACINGS........................................................ 283. LOADS ON FORMWORK.............................................................................................. 30

EXERCISE 1: FORMWORK CALCULATIONS................................................................ 32ACTIVITY 1: BASIC INFORMATION................................................................................ 32

4. USE OF TABLES AND GRAPHS TO DESIGN FORMWORK..................................... 33EXERCISE 2: FALSEWORK................................................................................................ 38

5. DROP PANELS AND HOPPER HEADS AS COLUMN CAPITALS............................ 39EXERCISE 3: CAPITALS AND COLUMNS....................................................................... 41

6. CONSTRUCTION WORKERS’ DUTIES....................................................................... 42EXERCISE 4: CONCRETE WORKERS DUTIES............................................................... 43

7. QUALITY CONTROL PROCEDURES TO ENSURE CORRECT SHAPE, SIZE ANDALIGNMENT ......................................................................................................................44

EXERCISE 5: QUALITY....................................................................................................... 458. WORKING DRAWINGS ................................................................................................. 46

EXERCISE 6: WORKING DRAWINGS .............................................................................. 47ACTIVITY 2: DESIGN FORMWORK ................................................................................. 48

9. CALCULATION OF MATERIAL QUANTITIES........................................................... 49EXERCISE 7: CONCRETE CALCULATIONS................................................................... 52

10. WORKING PLATFORMS FOR WALLS AND COLUMNS......................................... 53EXERCISE 8: PLATFORMS................................................................................................. 56SUMMARY............................................................................................................................. 57

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SECTION 2 - SETTING OUT, CONSTRUCTING AND ASSEMBLING ........................59

INTRODUCTION....................................................................................................................591. SETTING OUT FALSEWORK AND FORMWORK.......................................................59

EXERCISE 9: SETTING OUT ...............................................................................................612. CONSTRUCTING FALSEWORK AND FORMWORK FOR A SUSPENDED SLABAND BEAMS........................................................................................................................62

EXERCISE 10: SLAB AND BEAM FORMWORK .............................................................693 LOCATE, CONSTRUCT AND FIX LIFT AND SERVICE PENETRATIONS ................70

EXERCISE 11: SERVICE PENETRATIONS .......................................................................724. STAIRS AND LANDINGS ...............................................................................................73

SUMMARY.............................................................................................................................74

SECTION 3 - STRIPPING, CLEANING AND STORING FORMWORK ANDFALSEWORK ............................................................................................................................75

INTRODUCTION....................................................................................................................751. STRIPPING FORMWORK..............................................................................................752. STRIPPING SEQUENCE AND EQUIPMENT REMOVAL...........................................783. BACKING OFF OF FALSEWORK AND ADJUSTMENT HARDWARE......................804. REMOVAL, DENAILING, CLEANING AND STORING OF FORMWORK.................81

SUMMARY.............................................................................................................................83EXERCISE 12: STRIPPING, CLEANING AND STORING................................................84ACTIVITY 3: ERECT AND STRIP FORMWORK.............................................................85CONCLUSION........................................................................................................................86

ANSWERS...............................................................................................................................87

EXERCISE 1: FORMWORK CALCULATIONS .................................................................87EXERCISE 2: FALSEWORK.................................................................................................87EXERCISE 3: CAPITALS AND COLUMNS .......................................................................89EXERCISE 4: CONCRETE WORKERS DUTIES ...............................................................91EXERCISE 5: QUALITY........................................................................................................93EXERCISE 6: WORKING DRAWINGS...............................................................................95EXERCISE 7: CONCRETE CALCULATIONS....................................................................97EXERCISE 8: PLATFORMS..................................................................................................97EXERCISE 9: SETTING OUT ...............................................................................................99EXERCISE 10: SLAB AND BEAM FORMWORK ...........................................................101EXERCISE 11: SERVICE PENETRATIONS .....................................................................101EXERCISE 12: STRIPPING, CLEANING AND STORING..............................................103

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LIST OF ILLUSTRATIONS

Page

Figure 1 SLABS AND BEAMS..................................................................................... 28

Figure 2 SCHEMATIC DIAGRAM OF FORMWORK AND FALSE WORK FOR A

SUSPENDED SLAB.............................................................................................. 29

Figure 3 OPEN SPANDREL ARCH 1 AND ARCH 2 ................................................. 29

Figure 4 SAFE LOADS FOR PROPS IN DIFFERENT LENGTHS............................ 33

Figure 5 PLAN FOR SUSPENDED SLAB AND BEAM STRUCTURE SHOWING

THE LAYOUT OF PROPS AND FORMWORK FOR BEAM........................... 35

Figure 6 MAXIMUM SAFE AREA FOR PROPS........................................................ 36

Figure 7 LAYOUT OF JOISTS AND BEAMS............................................................. 37

Figure 8 DROP PANEL AND HOPPER HEAD........................................................... 39

Figure 9 PARTS OF A COLUMN................................................................................. 39

Figure 10 SQUARE AND RECTANGULAR PRISM.................................................. 40

Figure 11 FORM FACING LAYOUT FOR RECTANGULAR COLUMN................ 40

Figure 12 HOPPER HEAD TOGETHER WITH DROP PANEL ................................ 40

Figure 13 CORRECT DIRECTION FOR PLACING SLAB CONCRETE ................. 42

Figure 14 ALLOWABLE VARIATION IN SURFACE OF CONCRETE

(EXAGGERATED)................................................................................................ 44

Figure 15 SECTION SHOWING SLAB AND BEAM CONSTRUCTION................. 46

Figure 16 RECTANGULAR PRISM............................................................................. 49

Figure 17 RECTANGULAR PRISM............................................................................. 50

Figure 18 CYLINDRICAL PRISM................................................................................ 50

Figure 19 CIRCULAR COLUMN ................................................................................. 51

Figure 20 WORK PLATFORM AT TOP OF SCAFFOLD TOWER .......................... 53

Figure 21 TUBULAR METAL MOBILE TOWER ...................................................... 54

Figure 22 ANCHORAGE OF TALL PLATFORMS .................................................... 55

Figure 23 WORK PLATFORM CONSTRUCTED ALONGSIDE EDGE BEAM OF A

SLAB....................................................................................................................... 55

Figure 24 CENTRE LINE............................................................................................... 60

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Figure 25 GRID LINES USED TO SHOW LOCATIONS ...........................................60

Figure 26 SLABS AND BEAMS ...................................................................................62

Figure 27 WORK PLATFORM AT EDGE OF SLAB SUPPORTED BY PROPS.....63

Figure 28 BEAM SUPPORTS IN THIS EXAMPLE ALLOW DANGEROUS

UNBALANCE TO EXIST .....................................................................................63

Figure 29 THE PROBLEM OF ECCENTRICITY IS AVOIDED IF THE LOAD IS

ALWAYS INSIDE THE SUPPORTS ...................................................................64

Figure 30 STRIPPING BAND AT BEAM SIDE ALLOWS SLAB SOFFIT TO BE

STRIPPED WITHOUT DISTURBING THE BEAM ...........................................64

Figure 31 TOLERANCE GAP WITH CLOSURE ANGLE AT BEAM SIDE

ALLOWS EASY STRIPPING OF BEAM SIDE WITHOUT DISTURBING

SOFFITS..................................................................................................................65

Figure 32 TYPICAL DEEP BEAM FORMWORK WITH TIES..................................65

Figure 33 TYPICAL DEEP EDGE BEAM FORMWORK SHOWING TIES AND

THE USE OF SPREADER BAR AND STRUT TO KEEP THE BEAM PLUMB66

Figure 34 TYPICAL TIES ARE THE ‘HE BOLT’ SYSTEM ......................................66

Figure 35 THE EFFECTS OF MOUNDING .................................................................67

Figure 36 TYPICAL PENETRATIONS.........................................................................70

Figure 37 STRUCTURE OF RECTANGULAR PENETRATION ..............................71

Figure 38 DETAIL OF STAIR FORMS.........................................................................73

Figure 39 DETAIL OF WHOLE STAIRCASE .............................................................73

Figure 40 FORMWORK INCORPORATING PROPS WITH COLLARS TO STRIP

WITHOUT REMOVING PROPS..........................................................................76

Figure 41 UNDESIRABLE DISTORTION OF SLAB LIKELY WHEN BEAMS ARE

STRIPPED FIRST...................................................................................................77

Figure 42 THE BACKPROPPING PROCEDURE........................................................78

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CONSTRUCTION INDUSTRY COMPETENCY FRAMEWORK

ALL STREAMS

STAGE 4 (& BEYOND) SPECIALISED SKILLS

• Advanced Technical Skills• Supervisory Skills• Management Skills• Para-professional Skills• Professional Skills

(Currently under development)

BASE TRADE Õ × × ×FIELD OF WORK SKILLS

CIVIL OPERATIONS

z

z

STRUCTURES

zz zz zz

zz zz zz

zz zz zz

zz

FITOUT AND FINISH

zz

zz

zz

SERVICES(NON-TRADE)

zz zz

zz

SERVICETRADES

OFF-SITE

×BASIC STREAM SKILLS

CIVIL OPERATIONS STRUCTURES FITOUT & FINISH SERVICES

× ××× CurrentlyUnder

BASIC INDUSTRY SKILLS Development

CIVIL OPERATIONS STRUCTURES FITOUT & FINISH SERVICES

INCORPORATING INDUSTRY INDUCTION

Every stage produces a range of practical skillsEndorsed by Standards Committee 13/12/95

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CCC348 - Formwork: Suspended Slab and Beam INTRODUCTION

Australian National Training Authority 11

INTRODUCTION

CCC348 - Formwork: Suspended Slab and Beam is a module intended for use bythose completing Stage 3 of a specific FIELD OF WORK within a SKILL STREAM ofthe National Construction Industry Competency Framework.

The theoretical components of this package will enable you to complete the practicalrequirements of this module All set tasks, including the activities and demonstrations,will show how the theory or content can be applied in a practical manner in on-site orsimulated on-site conditions

Formwork: Suspended Slab and Beam is a module which deals with the knowledgeand skills required to set out a simple building structure and so includes specific detailson:

• formwork details and drawings;• formwork systems;• material quantities;• tools, equipment and personal protective equipment;• set out points and datum lines;• erection of scaffolding, falsework and handrails ;• penetrations and blockouts;• formwork and falsework for safety and quality;• formwork: selection, cleaning and release agent;• supervision during concrete pour;• formwork stripping methods;• falsework and formwork: cleaning, storage and removal from site;• falsework alignment techniques; and• back propping methods.

Two Assessment Tasks meet the requirements of the three Learning Outcomes:

Assessment Task 1

• Assessment of Knowledge

You will be given an assignment for assessment and asked to provide workingdrawings to demonstrate your knowledge related to the principles, planning andquality assurance procedures for construction of suspended slab and beam formwork.

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Australian National Training Authority12

• Task

Complete a graphics presentation, approximately 4 hours in duration, to developworking drawings that cover the formwork and falsework required for suspendedslab and beam construction.Complete an assignment, approximately 4 hours in duration, that covers suspendedslab and beam formwork including:

< plan and specification interpretation;< design spacings; and< working drawings.

Complete a written assignment, approximately 1 hour, that covers slab and beamformwork to cover:

< strength, safety and economy;< material quantities;< concrete workers’ duties before, during and after concrete placement;

and< erection and stripping sequences.

Assessment Task 2

• Assessment of Skills

You will be required to construct a formwork for a suspended slab and beamstructure.You will be working in a team with a maximum of four people, and you mustdemonstrate your individual skills and knowledge as part of that team.

• Task

Set out, fabricate and position formwork for a reinforced concrete slab withintersecting and perimeter beams, that encompasses the following specifications:

< a slab of minimum size 6000mm long x 6000mm wide and 300mmthick;

< intersecting and perimeter beams, minimum end section size 300mmwide x 400mm deep or similar;

< Soffit height minimum two unit frames from floor datum point; and< perimeter working platform – minimum 450mm.

This learning package has therefore been developed with three sequential sections,each being closely aligned with one or more of the two Assessment Tasks:

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SECTION 1: This contains learning resource material, self-checks and practicalexercises required for the successful completion of the AssessmentCriteria as shown in the Assessment Specification for Task 1.

SECTION 2: This section contains the information and practical work that willhelp you successfully complete part of Task 2.

SECTION 3: In a similar manner, this section will cover material, self-checks andpractical work that will help you successfully complete Task 2.

As well as self-check exercises and practical activities, your instructor will scheduleadditional oral and/or written tests which may be similar to the self-check exercises.These tests will satisfy specific Assessment Criteria in the Assessment Tasks and willapply to your work environment.

When you have achieved all the Assessment Criteria in all the Assessment Tasks,and your work has been checked and certified by your instructor, you will havesuccessfully completed the Learning Outcomes which make up the total off-the-jobcomponent of the whole moduleCCC348 Formwork - Suspended Slab and Beam.

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OVERVIEW

CCC348 - Formwork: Suspended Slab and Beam - A Stage 3 Module

The overall competencies for this module are summed up in the purpose statement:

PURPOSE: To provide building and construction workers with the knowledge andskills required to construct formwork for reinforced concretesuspended slab and beam structures including column capitals.

In the next section on Module Details, you will find specific details about the TrainingSpecification and how you will be assessed

In general terms, CCC348 - Formwork: Suspended Slab and Beam covers:

The Skills/Competenciesrequired for this module

The Theory/Content required to achieve these skills/competencies

• The ability to apply the principles offormwork in the design, planning andquality control

• The ability to set out, construct andassemble falsework and formwork.

• The ability to strip, clean and storefalsework and formwork.

• Formwork Member Sizes and Spacings• Falsework Member Sizes and Spacings• Loads on Formwork• Use of Tables and Graphs to Design

Formwork• Drop Panels and Hopper Heads• Construction Workers’ Duties• Quality Control Procedures• Working Drawings• Calculation of Material Quantities• Working Platforms• Setting Out Falsework and Formwork• Constructing Falsework and Formwork• Locate, Construct and Fix Penetrations• Stairs and Landings• Stripping Formwork• Stripping Sequence and Equipment

Removal• Backing-Off of Falsework• Removal, Denailing, Cleaning and Storing

Formwork

When you have successfully achieved all the Assessment Criteria for theAssessment Tasks, you will have completed the requirements for this module.

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WHAT IS PROVIDED

You will be provided with the essentials to successfully complete this module,including:

• plans and specifications;• equipment;• timber and plywood; and• falsework.

WHAT YOU PROVIDE?

• appropriate personal protective clothing etc - to be advised by yourinstructor;

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HOW TO USE THIS PACKAGE

This package has been designed so that you can work and learn at your own pace,incorporating into your own learning program.

• demonstrations of practical skills by your instructor or experiencedtradesperson;

• planned and supervised practical application of your knowledge andskills;

• instruction in, and application of, safe working practices; and• personal progress indicators through self-check exercises and practical

activities.

It is suggested that you work through the three sections as they are presented.

By all means, fast-track any aspects/areas where you feel confident.

Self-Check Exercises have been included so that you can measure your own progress.These exercises, however, are not part of the formal assessment of competency.

The module Formwork: Suspended Slab and Beam, has a nominal duration of 54 -66 hours, but you may take more or less time working at your own pace.

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GETTING TO “KNOW THE PACKAGE”

Here is a strategy which may help you become familiar with the contents of thispackage.

• Survey Scan the whole package

Read the contents page and the introduction, then flip through the pages -glance at the headings.

Notice that there are set tasks to be completed. The content relates tothese tasks.

• Ask Ask about any topics, terms or details that are not clear to you at thisstage.

• Read Read through the material, but do it actively. Jot down points, underlineor highlight.

Link the information with what you know already.

Let the headings and sub-headings help you organise information.

Remember that you will need the content to complete the tasks.

• Review At various stages, you will be directed to review the main points orcomplete a Self-Check Exercise to indicate how you are progressing.

Make your own notes as well.

• Instructor Throughout this package, you will be required to attend practicaldemonstrations and receive instruction in the use of materials, tools andequipment.

Ask your instructor if you have any problems with:

< interpretation of content;< procedures or processes; or< availability of resources

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KEY TO SYMBOLS

Symbols are placed in the left hand margin to draw attention to the type of informationcommencing at that point.

The symbols used in this package are:

READ Read This is the essential information forthe module.

DEMONSTRATION Instructor Demonstration At times, your instructor will givepractical advice and demonstratethe use of tools/equipment.

SELF-CHECK Self-Check Exercise These are your progress indicators.Typical answers are also included.

PRACTICALACTIVITY

Practical Activity The seven activities allow for theapplication of the theorycomponents.

SITE VISIT Site Visit

Your instructor will schedule visitsto appropriate sites.

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CCC348 - Formwork: Suspended Slab and Beam MODULE DETAILS


MODULE INFORMATION: from the Training Specification

MODULE TITLE Formwork: Suspended Slab and Beam

Nominal Duration 54 - 66 Hours

Module Number CCC348

Purpose To provide building and construction workers with theknowledge and skills required to construct formwork forreinforced concrete suspended slab and beam structuresincluding column capitals.

Relationship toCompetency Standards

National Building and Construction Industry CompetencyStandards:

• ST 3046 Erect and Dismantle Formwork

Pre-requisites • Basic Stream Skills

A trainee may seek recognition through the R.P.L. process forcompetencies already held.

Summary of Content • The Principles of formwork design, planning andquality control.

• Setting out, constructing and assembling falsework andformwork.

Delivery Delivery methods must provide for the demonstration ofcompetence in skills specified in all learning outcomes, either inon-site or simulated on-site conditions.

Suggested LearningResources

• AS 1657–1992 Fixed Platforms, Walkways, Stairwaysand Ladders – Design, Construction and Installation.

• AS 3610–1995 Formwork for Concrete.• AS 3610 Supplement 2 (1992).• The Concrete Society, London 1989 Formwork, A Guide

to Good Practice.• Fletcher, B. G. and Lavan S. A. Civil Engineering

Construction Heinemann, London, 1987.

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Suggested LearningResources (conti)

• McAdam, P.S. (1993) Formwork: A Practical Approach.Stuart Publications, Brisbane.

• Walsh, P. Use of the Australian Standard for ConcreteStructures Inkata Press, Melbourne, 1988.

• Wilshere, C.J. (1989) Formwork Thomas Telford Ltd,London.

• Wynn, A.E. & Manning, G.P. (1974) Design ofFormwork for Concrete Structures Cement and ConcreteAssociation, London.

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ASSESSMENT INFORMATION

CCC348 - Formwork: Suspended Slab and Beam is a module in the NationalConstruction Industry Competency Framework.

The program focuses on the achievement of learning outcomes measured againstassessment criteria based on National Competency Standards.

All learning outcomes must be successfully achieved if you are to be awardedcompetence in this module.

Your assessment will be recorded as:

• Competent; or• Not Yet Competent.

You will have completed the learning outcomes when you have successfully achievedall the Assessment Criteria in Assessment Tasks. One or more of the followingassessment methods will be used:

• supervised assessment in the demonstration of techniques;• a number of written and/or oral assessments;• practical activities, allowing for demonstrations of your ability in the

assessment tasks.

All projects are to be carried out on-site or in simulated on-site conditions.��



ASSESSMENT SPECIFICATION

MODULE TITLE FORMWORK: SUSPENDED SLAB AND BEAM

Module Number CCC348

Purpose of the Assessment To demonstrate underpinning knowledge related to theprinciples, planning and quality assurance procedures forconstruction of suspended slab and beam formwork.

Instructions for theAssessee

The following procedures could be carried out in one or moreprojects:

Assessment Task 1

• Complete a graphics presentation, approximately 4hours in duration, to develop working drawings thatcover the formwork and falsework required forsuspended slab and beam construction.

• Complete an assignment, approximately 4 hours induration, that covers suspended slab and beamformwork including:

< plan and specification interpretation< design spacings< working drawings.

• Complete a written assignment, approximately 1hour, that covers slab and beam formwork to cover:

< plan and specification interpretation;< design spacings; and< working drawings.

Assessment Task 2

• Set out, fabricate and position formwork for areinforced concrete slab with intersecting and perimeterbeams, that encompasses the following specifications:

< a slab of minimum size 6000mm long x6000mm wide and 300mm thick.

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< intersecting and perimeter beams, minimumend section size 300mm wide x 400mm deepor similar

< soffit height minimum two unit frames fromfloor datum point

< perimeter working platform - minimum450mm

Guidelines for the Assessor This is a supervised assessment.

This is an assessment of the final product. However someobservation of the process will be involved, this is detailed onthe checklist.

Learning Outcome AssessmentTask 1

AssessmentTask 2

CCC348.1 Yes

CCC348.2 Yes

CCC348.3 Yes��



ASSESSMENT TASKS

ASSESSMENT TASK 1:

• Complete a graphics presentation, approximately 4 hours in duration,to develop working drawings that cover the formwork and falseworkrequired for suspended slab and beam construction.

• Complete an assignment, approximately 4 hours in duration, that covers

suspended slab and beam formwork including:

< plan and specification interpretation< design spacings< working drawings

• Complete a written assignment, approximately 1 hour, that covers slaband beam formwork to cover:

< strength, safety and economy< material quantities< concrete workers’ duties before, during and after concrete

placement< erection and stripping sequences.

The procedures above could be carried out in one or more projects.

Assessment Task 1 incorporates Learning Outcome 1: Apply the Principles of Formwork inthe Design, Planning and Quality Control.

Item Assessment Criteria Achieved

1. Suspended slab and beam formwork member sizes and spacings areselected to withstand dead and live loads and wind forces, from basicformwork span tables.

2. Falsework members and their spacings are incorporated into the designof suspended slab and beam structures.

3. Construction workers duties before and after concrete placement arestated.

4. Drop panels and hopper heads which act as column capitals aredesigned as an integral part of suspended slab and beam formwork.

5. Quality control procedures are incorporated into the constructionprocess to ensure correct shape, size and alignment of concretestructures.

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6. Working drawings for suspended slab, beam and capital formwork areproduced from plans and specifications.

7. Material quantities are calculated for suspended slab and beamformwork.

8. Working platforms are incorporated into wall and column formwork.

All work practices must ensure that current OH&S requirements are adopted.

• Items 1 to 8 must be performed fully.

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ASSESSMENT TASK 2:

Set out, fabricate and position formwork for a reinforced concrete slab withintersecting and perimeter beams, that encompasses the following specifications:

< a slab of minimum size 6000 mm long x 6000 mm wide and 300 mm thick< intersecting and perimeter beams, minimum end section size 300 mm

wide x 400 mm deep or similar< Soffit height minimum two unit frames from floor datum point< perimeter working platform – minimum 450 mm.

Assessment Task 2 incorporates Learning Outcomes:

2. Set Out, Construct and Assemble Falsework and Formwork.3. Strip, Clean and Store Falsework and Formwork.

Item Assessment Criteria Achieved

1. Falsework and formwork for suspended slab and beam structures areset out using centre lines, off set grids, datums and reduced levels.

2. Falsework and formwork for suspended slab , beam and capitalcomponents are constructed using both timber and proprietary forms.

3. Lift and service penetrations are located, constructed and fixed inaccordance with plans and specifications.

4. Beam sides are constructed, located and braced to lines and heightsspecified in the plans and specifications.

5. Hand rails and toe boards are erected in accordance with statutoryregulations.

6. Plans and specifications are checked for designed stripping times.

7. Stripping sequence and equipment removal is planned.

8. Falsework and adjustment hardware are backed off to allow ease ofstripping.

9. Falsework and formwork is safely and sequentially removed, denailed,cleaned and relocated.

All work practices must ensure that current OH&S requirements are adopted.

• Items 1 to 9 must be performed fully.

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CCC348 - Formwork: Suspended Slab and Beam SECTION 1


SECTION 1 - THE PRINCIPLES OF FORMWORK DESIGN,PLANNING AND QUALITY CONTROL

READ

INTRODUCTION

This first section of this package deals with four main aspects:

• design and planning;• quality control;• calculation of materials; and• working platforms.

These areas include the essential information you will need to complete AssessmentTask 1 which addresses the first learning outcome:

Apply the principles of formwork design, planning and quality control.

The details required for this section will be presented under ten topics:

• Formwork Member Sizes and Spacings• Falsework Member Sizes and Spacings• Loads on Formwork• Use of Tables and Graphs to Design Formwork• Drop Panels and Hopper Heads as Column Capitals• Construction Workers’ Duties• Quality Control Procedures to Ensure Correct Shape, Size and

Alignment• Working Drawings• Calculation of Material Quantities• Working Platforms for Walls and Columns

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1. FORMWORK MEMBER SIZES AND SPACINGS

In concrete construction two important structural elements are slabs and beams. Aslab is a large, flat piece of concrete usually in the shape of a square or a rectanglewhich usually forms the main part of a floor or a roof. A beam, on the other hand, is along, thinner part of a structure used as support for some other structure such as a slab.Beams can also be built to stand alone.

The size and spacing of beams and formwork are carefully designed by engineers whotake into account the loads the slabs and beams will have to support. All slab and beamdimensions and spacing dimensions are given in full in the engineer’s workingdrawings for the building project.

Size and spacing will therefore vary from one job to the next and will fit in with what isknown as standard good practice. Size and spacing of slabs and beams will also followthe formwork code as laid out in AS 3610.

2. FALSEWORK MEMBER SIZES AND SPACINGS

Falsework is the temporary structure needed to support the permanent structure while itis being erected. Falsework actually includes the formwork. Usually when we speak offalsework, we usually refer to the structure that supports the formwork - that is, thestructure on which the formwork rests. We mean the joists, bearers, props, and anyother stabilising structures such as wedges, soleplates. Falsework also includesscaffolding and work platforms. Figure 2 shows formwork for a suspended slab. Thediagram does not show formwork for the edges, scaffolding or work platforms.

Figure 1 SLABS AND BEAMS

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Falsework may be constructed from round or sawn timbers, steel joists, or scaffoldtubing. In bridge construction, falsework can take the form of temporary piles.Sometimes wedges and jacks are incorporated in falsework. This is done to make iteasier to dismantle a job once it is completed.

Falsework designed to carry heavy loads is sometimes made up of metal cylinders filledwith dry sand supporting a plunger. These cylinders are known as sandboxes.Falsework is mostly used in river and harbour works and in the construction of arches.Two styles of arch bridge are illustrated here.

Figure 2 SCHEMATIC DIAGRAM OF FORMWORK AND FALSEWORK FOR A SUSPENDED SLAB

Figure 3 OPEN SPANDREL ARCH 1 AND ARCH 2

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3. LOADS ON FORMWORK

Loads are expressed as pressures which are measured in units called Pascals. Thesymbol is Pa. One Pascal is about 100 grams (roughly the weight of a Mars bar) spreadover an area of one square metre. It’s a small unit, and when we talk of concrete itmakes better sense to talk in terms of thousands of Pascals - Kilopascals (kPa).

Loads on formwork come from a number of sources:

Self weight - is the weight of all materials used to construct the form.

Concrete loads - because the concrete acts like a liquid the forces can be assumed toincrease in the same way as liquid in a column. That is, the pressure of the liquidincreases the deeper you go. The pressure on the form due to concrete can be easilycalculated.

Live loads - are the weight of the workers, their equipment and building materials. Ifthe formwork is to be used as a place to store materials then it must be designed toaccept it. If the formwork needs to support further work above it such as a multi-levelbuilding then it must be strong enough. Extra loads may be produced by mounding ofconcrete or by starting the pour at the wrong position, where there is no prop directlyunderneath. The formwork should include some margin of strength to cope with theseerrors.

Wind and water loads - wind will catch the formwork. The loads due to wind can behigh. They will vary with climate and location. Rain and run off can add loads onformwork and can soften the foundations or remove soil, causing footings to shift.

Impact loads from concrete buckets, trucks or other objects could cause damage to theformwork. If this happens the pour should be terminated and repairs undertaken. Theformwork should be braced so that in the event of a serious impact it will not collapsetotally. The formwork should not only be strong but also cross braced so that damageis minimised.

Earthquake loads - are considered important only if the formwork is likely to beerected 6 months or more.

Other loads may come from things like shrinkage of concrete or shifting of footings.

Loads must be considered at three stages of the building process:

Stage 1 - before placing the concrete

Stage 2 - during placement of concrete

Stage 3 - After placement of concrete, until concrete is able to support the appliedloads. Some of the loads described above can be calculated. Others are estimatedbecause they are constantly changing and no accurate calculation can be made.

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The concrete load is calculated with the knowledge that concrete weighs about 2500 Kgper cubic metre. (Sometimes the figure 2400 is used). This is called it’s density and it’ssymbol is r (the Greek letter ‘rho’).The self weight of formwork is normally fairly predictable. It is estimated to be 0.1kPa.

The live loads are estimated to be 1.0 kPa for the workers and their equipment, 3.0 kPafor concrete mounding and 4.0 kPa for building materials. These are obtained fromAustralian Standard 3610.

All of the loads are added to obtain the total load.

Calculation of concrete load

Formula used : Load = (rho) x h / 100

Where rho is 2500 and h is the depth of the concrete

Example 1:

(a) Calculate the load due to a concrete slab 200 mm thick

L = rho x h / 100 = 2500 x 0.2 / 100 = 5.0 kPa

Calculate the total load on the props

Total load = 5.0 (concrete) + 0.1 (self load) + 1.0 (workers and equipment) + 3.0Mounding + 4.0 Materials = 13.1 kPa

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SELF-CHECK

EXERCISE 1: FORMWORK CALCULATIONS

1. Calculate the concrete load due to a slab 250 mm thick.

____________________________________________________________________

____________________________________________________________________

2. Assume that the slab is to be suspended by formwork and props. Calculate thetotal load on the props due to the formwork, live loads, concrete and stackedmaterials.

____________________________________________________________________

____________________________________________________________________

PRACTICALACTIVITY

ACTIVITY 1: BASIC INFORMATION

1. Draw small pictorial sketches of:

• a slab• a beam• a slab supported by two beams

2. In your own words tell what is meant by standard good practice.

____________________________________________________________________

____________________________________________________________________

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4. USE OF TABLES AND GRAPHS TO DESIGN FORMWORK

There are ways of deciding on the spacing of supporting falsework beams and joists.One way of doing it is to use tables which show the safe loads that can be carried byjoists and props at given spacing. Figure 4 shows the safe loads that can be carried byprops of given length. Table 1 gives the spacing of joists required to support givenloads. On the job, props used to support the formwork are often hired, and the suppliermay provide a design service which sets out the spacing of the props. Figure 5 Shows asection of a plan for a slab and beams which shows the set out of props and workingdrawings for the formwork to support the beams.

Figure 4 SAFE LOADS FOR PROPS IN DIFFERENT LENGTHS

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IDCode

StressGrade

Face grain parallel to spanSpan (l) mm

Face grain perpendicular to spanSpan (l) mm

225 300 400 450 480 600 800 900 225 300 400 450 480 600 800 90012-10-5 F11 39.4 22.2 12.5 9.9 7.7 3.2 55.6 31.3 17.6 11.4 8.8 3.6

F14 50.2 28.2 15.9 11.4 8.8 3.6 70.7 39.8 20.8 13.0 10.0 4.1F17 61.0 34.3 19.3 13.3 10.3 4.2 85.9 48.3 24.3 15.2 11.7 4.8F22 78.9 44.4 24.3 15.2 11.7 4.8 86.4 62.5 27.8 17.3 13.4 5.5F27 86.4 55.5 28.1 17.5 13.5 5.6 86.4 64.8 32.1 20.0 15.5 6.3 2.0

12-10-7 F11 44.8 25.2 14.2 10.7 8.2 3.4 53.8 30.3 17.0 11.4 8.8 3.6F14 57.0 32.1 18.1 12.2 9.4 3.9 68.4 38.5 20.8 13.0 10.0 4.1F17 69.3 39.0 21.9 14.2 11.0 4.5 83.1 46.8 24.3 15.2 11.7 4.8F22 87.8 50.4 26.0 16.2 12.6 5.1 87.8 60.5 27.8 17.3 13.4 5.5F27 87.8 63.0 30.1 18.8 14.5 5.9 87.8 65.9 32.1 20.0 15.5 6.3 2.0

12-13-5 F11 44.8 25.2 14.2 10.7 8.2 3.2 52.0 29.2 15.9 10.0 7.7 3.2F14 57.0 32.1 18.1 12.2 9.4 3.9 66.2 37.2 18.2 11.4 8.8 3.6F17 69.3 39.0 21.9 14.2 11.0 4.5 80.3 45.2 21.3 13.3 10.3 4.2F22 85.6 50.4 26.0 16.2 12.6 5.1 85.6 58.5 24.3 15.2 11.7 4.8F27 85.6 63.0 30.1 18.8 14.5 5.9 85.6 64.2 28.1 17.5 13.5 5.6

12-16-5 F11 53.8 30.3 17.0 13.4 10.4 4.3 48.4 27.2 14.8 9.2 7.1 2.9F14 68.4 38.5 21.7 15.4 11.9 4.9 61.6 34.7 16.9 10.6 8.1 3.3F17 83.1 46.8 26.3 18.0 13.9 5.7 74.8 42.1 19.7 12.3 9.5 3.9F22 87.8 60.5 33.0 20.6 15.9 6.5 2.1 87.8 54.5 22.6 14.1 10.9 4.5F27 87.8 65.9 38.1 23.8 18.4 7.5 2.4 87.8 65.9 26.1 16.3 12.6 5.2

12-25-5 F11 67.6 38.3 21.6 16.3 12.6 5.2 30.5 17.1 8.0 5.0 3.8F14 77.0 48.8 27.4 18.7 14.4 5.9 38.8 21.8 9.1 5.7 4.4F17 86.4 59.2 33.3 21.8 16.8 6.9 2.2 47.1 26.5 10.6 6.6 5.1 2.1F22 86.4 64.8 39.9 24.9 19.2 7.5 2.4 61.0 34.3 12.1 7.6 5.9 2.4F27 86.4 64.8 46.1 28.8 22.2 9.1 2.0 76.2 42.9 14.0 8.8 6.8 2.8

15-32-5 F11 84.5 59.5 33.5 26.4 23.2 10.1 3.2 2.2 46.6 26.2 14.8 9.2 7.1 2.9F14 96.2 72.2 42.6 33.7 28.2 11.6 3.7 2.5 59.3 33.4 16.9 10.6 8.1 3.3F17 108.0 81.0 51.7 40.9 32.9 13.5 4.3 3.0 72.0 40.5 19.7 12.3 9.5 3.9F22 108.0 81.0 60.7 48.7 37.6 15.4 4.9 3.4 93.2 52.4 22.6 14.1 10.9 4.5F27 108.0 81.0 60.7 54.0 43.5 17.8 5.6 3.9 108.0 65.5 26.1 16.3 12.6 5.2

17-10-7 F11 78.9 44.4 25.0 19.7 17.3 8.8 2.8 95.7 59.5 33.5 26.4 23.2 10.3 3.3 2.3F14 100.0 56.5 31.8 25.1 22.1 10.0 3.2 2.2 109.0 75.7 42.6 33.7 28.9 11.8 3.7 2.6F17 122.0 68.6 38.6 30.5 26.6 11.7 3.7 2.6 122.0 91.8 51.7 40.9 33.7 13.8 4.4 3.0F22 122.0 88.7 49.9 39.4 32.6 13.4 4.2 2.9 122.0 91.8 66.9 49.8 38.5 15.8 5.0 3.5F27 122.0 91.8 62.4 48.8 37.7 15.5 4.9 3.4 122.0 91.8 68.8 57.6 44.5 18.2 5.8 4.0

17-13-7 F11 89.6 50.4 28.4 22.4 19.7 10.1 3.2 2.2 98.0 59.5 33.5 26.4 23.2 10.3 3.3 2.3F14 112.0 64.2 36.1 28.5 25.1 11.6 3.7 2.5 112.0 75.7 42.6 33.7 28.9 11.8 3.7 2.6F17 125.0 77.9 43.8 34.6 30.4 13.5 4.3 3.0 125.0 91.9 51.7 40.9 33.7 13.8 4.4 3.0F22 125.0 93.9 56.7 44.8 37.6 15.4 4.9 3.4 125.0 93.9 66.9 49.8 38.5 15.8 5.0 3.5F27 125.0 93.9 70.4 56.0 43.5 17.8 5.6 3.9 125.0 93.9 70.4 57.6 44.5 18.2 5.8 4.0

17-14-7 F11 86.0 48.4 27.2 21.5 18.9 9.4 3.0 2.1 95.2 56.5 31.8 25.1 22.1 9.2 2.9 2.0F14 108.0 61.6 34.7 27.4 24.1 10.8 3.4 2.4 108.0 71.9 40.4 31.9 25.7 10.5 3.3 2.3F17 122.0 74.8 42.1 33.2 29.2 12.6 4.0 2.8 122.0 87.3 49.1 38.8 30.0 12.3 3.9 2.7F22 122.0 91.2 54.5 43.0 35.1 14.4 4.6 3.2 122.0 91.2 63.5 44.4 34.3 14.1 4.4 3.1F27 122.0 91.2 68.1 52.6 40.6 16.6 5.3 3.7 122.0 91.2 68.4 51.3 39.7 16.2 5.1 3.6

Table 1 SPACING OF JOISTS FOR A SUSPENDED SLAB

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Figure 5 PLAN FOR SUSPENDED SLAB AND BEAM STRUCTURE SHOWINGTHE LAYOUT OF PROPS AND FORMWORK FOR BEAM

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The graphs and table are used in the following example.

Example 2: A suspended slab 200 mm thick is to be poured. The height will be 2.6 m.Decide with the use of tables and graphs;

the spacing of propsthe spacing of joists

Answer:

Step 1: Calculate the load on the props. We know from example 1 that a slab of 200mm will have a total load of 13.1 KPa, so we don’t need to calculate the load.

Step 2: Go to Figure 4, and find 2.6 m prop height.

Step 3: Find 200 mm slab depth on the horizontal axis.

Step 4: Find the point where the two lines from the axes intersect

Step 5: Choose the nearest curved line to the right of the point of intersection. Read thefigure at the end of the line. This is the area that the prop will safely support.

Answer = 1.5 square metres

What does the answer mean?

It means that the area supported by the prop must not be more than 1.5 square metres.From that information we can decide how far to space the props.

To decide on the spacing, we choose one prop and look at the nearest two props andform a rectangle.

So if distance from prop 1 to 2 is 1 m, then distance 1 to 3 cannot be more than 1.5 m.Combinations of distances in both directions can be used. If stronger props are chosenthe distances between props can be increased.

Figure 6 MAXIMUM SAFE AREA FOR PROPS

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• Spacing of Joists

Plastic coated plywood is commonly used as the formface material. This is made indifferent thicknesses and strengths. Tables such as those supplied by the PlywoodAssociation (Table 1) can be used to work out the spacing of joists.

Example 3: The 200 mm slab in example 2 is to be poured on 19 mm plywoodidentified by the code number 19-13-7, stress grade F11. Use the tables to decide howfar apart the joists should be placed.

Step 1: Calculate the pressure of the concrete. (we already know this fromprevious calculation, 13.1 KPa.)

Step 2: Use Table 1 to decide on the spacing of the joists. Find 19-13-7 and F11 inthe table. Then look across the table to find a figure just greater than 13.1 -you should see the figure 17.6 which will be in the column under 480 mm.That means that the plywood should have joists spaced no more than 480mm apart to avoid deflections.

Now we know the Prop spacing and the joist spacing and we can begin to design theformwork.

Figure 7 LAYOUT OF JOISTS AND BEAMS

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SELF-CHECK

EXERCISE 2: FALSEWORK

Write brief answers to these. Add sketches where appropriate:

1. What is falsework?

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

2. What materials are used for the construction of falsework?

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

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5. DROP PANELS AND HOPPER HEADS AS COLUMN CAPITALS

A drop panel is one placed to carry a high load. It is a part of a slab that is madethicker. Typically, a drop panel might be 100 mm thick. A hopper head is a funnelshaped capital for a column.

A column is an upright pillar, usually with a shaft often in the shape of a cylinder andwith a bottom piece known as a base. The top of a column is called a capital. Thesecomponents are shown in the following diagram.

Figure 8 DROP PANEL AND HOPPER HEAD

Figure 9 PARTS OF A COLUMN

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Columns can also be in the form of square or rectangular prisms.

Formwork for square or rectangular columns is usually made from plywood sheetingwith timber bearers spaced at intervals along the sheeting. Two sides of the columnwill have formwork the same width as the column while the formwork for the othertwo sides will be the width of the column plus the width of two plywood sheets toallow for overlapping as is shown below.

In construction, column capitals will be placed to support drop panels.A drop panel and hopper head may be used together.

Figure 10 SQUARE AND RECTANGULARPRISM

Figure 11 FORM FACING LAYOUT FORRECTANGULAR COLUMN

Figure 12 HOPPER HEAD TOGETHER WITH DROPPANEL

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SELF-CHECK

EXERCISE 3: CAPITALS AND COLUMNS

Write brief answers to these:

1. What is a capital?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2. What are the usual shapes of columns?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

3. Make a sketch of a hopper head.��



6. CONSTRUCTION WORKERS’ DUTIES

The quality of concrete work depends very much on the quality of the formwork andthe care taken a the time of the pour. The smoothness of surfaces in contact with theformwork for example depends on the formwork staying rigid as the concrete ispoured. Even if the formwork is of the right strength, it could be overloaded andproduce stress bulges. Tightness of the props and ties need to be checked before andduring the pour.

• Before Concrete Placement

All workers must be on duty and in place. They must all have appropriate clothingincluding steel-capped boots, gloves, goggles, long-sleeved shirts, sun protection andsafety helmets. Workers must all have immediate access to necessary equipment suchas trowels, levelling implements and vibrators. Compressors used for operating thevibrators will need to have been checked to see that they are operating properly.

• During Concrete Placement

Workers must again observe all occupational health and safety requirements. Cranes,buckets, winches, pulleys must all be watched carefully.

The formwork should be watched for movement. Ties and props in important positionsshould be checked for tightness.

The pour must be managed so that mounds are minimised and that the pour is in theright direction.

Special care must be taken near concrete trucks particularly when they are backing andturning.

• After Concrete Placement

The major tasks to be performed are levelling and smoothing.

Figure 13 CORRECT DIRECTION FORPLACING SLAB CONCRETE

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SELF-CHECK

EXERCISE 4: CONCRETE WORKERS DUTIES

Prepare a chart and on it list six duties to be performed on each of these occasions:

(a) Before a concrete pour (b) During a concrete pour (c) At the completion of a concrete pour

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7. QUALITY CONTROL PROCEDURES TO ENSURE CORRECTSHAPE, SIZE AND ALIGNMENT

Quality is an important thing to think about when placing and shaping concrete forms.When we speak of quality in concrete work we speak of two main things:

• correct shape, and• quality of surface

The concrete must be formed in its designed shape. It must also have a suitably high-quality finish with proper smoothness and be the right colour. Smoothness is affectedby the smoothness of the form face (any rubbish left on the form will be mirrored in thesurface of the concrete). It is also affected by the weight of the concrete itself - if theconcrete overstresses the formwork and makes it buckle, the result will be a ripplysurface. The Australian Standard sets maximum limits on surface irregularity.Typically surface ripple should be no more than about 1mm per metre of length.

The colour could vary from one panel of formwork to another. This could happen ifdifferent panels are used, or the release agent is changed. It could also happen becauseof slight changes in the concrete used or the setting time.

The concrete must be placed in its proper position. In other words, it must be alignedcorrectly. The dimensions of the slab or beam must be right.

To make sure that concrete is of a proper standard or quality, tests will take place.Samples will be taken in the form of cores of concrete which will be allowed to cure orset and then be tested in a laboratory.

Cores will be tested for what is known as compressive strength which is strength whencompressed under load. Tests of compressive strength are usually undertaken at the endof seven days when the concrete is at sixty per cent of its final strength and at twenty-eight days when the concrete is expected to have reached its final strength. In specialcases - particularly with a large job being finished quickly - sample cores for testingmay be taken at the end of three or four days.

Figure 14 ALLOWABLE VARIATION IN SURFACE OF CONCRETE(EXAGGERATED)

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SELF-CHECK

EXERCISE 5: QUALITY

Write TRUE of FALSE after each of these statements:

1. Alignment is where the concrete is positioned __________.

2. At the end of seven days concrete has reached its final strength __________.

3. Concrete is usually tested at the end of ten days and at the end of sixty days

_________.

4. Concrete for testing is taken in sample cores __________.

5. Sample cores are often taken earlier on large jobs __________.

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8. WORKING DRAWINGS

When a building is being designed the designers and draftsmen will produce a set ofdrawings which will show how every part of the building will be constructed. Thesedrawings will be exact and very detailed. They will also be extensive.

All building workers will need to be able to refer to and understand the workingdrawings that are being used in a building project. Figure 15 shows a section through asuspended slab including beams. You need to be able to find the location of slab edgesand beams. For specialised formwork the detail might be drawn, but often the designof formwork for simple slabs and beams is up to the formworkers.

Drawing skills are required as is basic knowledge and ability with computer assisteddrafting (CAD).

Figure 15 SECTION SHOWING SLAB AND BEAM CONSTRUCTION

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SELF-CHECK

EXERCISE 6: WORKING DRAWINGS

From Figure 15, identify the following:

1. slab area

2. perimeter beam

3. intersecting beams

You should be able to draw working drawings for formwork. This will be checked byyour instructor.

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PRACTICALACTIVITY

ACTIVITY 2: DESIGN FORMWORK

1. Design the formwork for a section of the plan in Figure 15. Your instructor willchoose the part of the plan for you. The section should contain both beams andslab and the beam forms should be designed for easy stripping.

2. Your instructor may ask you to construct the formwork.

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9. CALCULATION OF MATERIAL QUANTITIES

Quantities of materials used in major building projects are calculated by specialworkers called quantity surveyors and estimators who are highly trained specialists.

However you must be able to calculate approximate quantities of materials so that youknow what to expect and know when there is too little or too much.

Material quantities are calculated by basic arithmetic.

To assess the quantity of pre-mixed concrete for a slab or a beam, for instance, youfollow this method:

The basic method for any slab or beam is to calculate the area of one end andmultiply it by the depth or length. This works for any regular shape.

For a rectangular prism, the area of any side is length times width .

Formula used is:

Volume (V) = Length (L) x Width (W) x Depth (D)

All measurements are metric.

Example: Calculate the quantity of concrete required for a slab length 20 m, width10m, and thickness 250 mm.

Volume = Length (20 m) x Width (10 m) x Depth (0.25 m)= 20 x 10 x 0.25 cubic metres= 50 cubic metres

The same formula will be used for measuring square and rectangular beams andcolumns.

Figure 16 RECTANGULAR PRISM��



Example: Calculate the volume of concrete in a beam of width 400 mm, depth 300mm and length 5 m.

Volume = area of the end x length

V = L x W x D = 0.3 x 0.4 x 5.0 = 0.60 cubic metres

The same method is used for circular columns but the formula is different. The volumeof a circular column will be calculated by multiplying the area of the end (radius of thecolumn squared by 3.142 or pi (∏) by the height.

Volume = Area of end x heightThe formula used is:Volume = (∏) x R2 x H

Figure 17 RECTANGULAR PRISM

Figure 18 CYLINDRICAL PRISM

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Example: Calculate the volume of concrete required for a circular column ofdiameter 600 mm and 4 m high.

Volume = (∏) x R2 x H = 3.142 x 0.3 x 0.3 x 4 = 1.13 cubic metres

Figure 19 CIRCULARCOLUMN

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SELF-CHECK

EXERCISE 7: CONCRETE CALCULATIONS

1. Calculate the amounts of concrete required for these slabs:

7m x 12m x 300mm

8m x 20m x 250mm

15m x 30m x 500mm

2. Calculate the concrete required for these columns:

6m high x 1m in diameter

4m high x 600mm in diameter

10m high x 2m in diameter

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10. WORKING PLATFORMS FOR WALLS AND COLUMNS

The simplest kind of platform used with concrete construction is on a simplescaffolding frame or tower. At the level of the platform, a plank flooring is fitted. Theplatform is fitted with a handrail and a toe board and an access ladder is fitted eitherinside or outside the tower. (See Figure 20).

Working platforms can be part of towers that can be mobile or static.

Figure 20 WORK PLATFORM AT TOP OF SCAFFOLD TOWER

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A mobile platform will be set on wheels and contain a single working platform. Thiskind of platform is used mainly for light work such as inspection and painting.

A typical mobile platform is shown in the following diagram. Note the ladder which, inthis case, is on the outside. Ladders are also sometimes internal.

Note too, the handrail and the toe board. Both of these are necessary for safety as arethe locking devices fitted to the wheels.

Static platforms are held permanently in place and will not be moved. They are used asworking or observation platforms.

If a tower is more than ten metres high it must be tied to the main structure. It must alsobe braced so that it remains rigid.

Other steps are taken to make sure that the towers supporting static towers remain rigid.

Figure 21 TUBULAR METAL MOBILE TOWER

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Tie wires are fitted for every ten metres in height. These are set at 45º from the groundand fixed to anchorage points as shown below.

Note that sometimes working platforms are attached to hoists. Cherry pickers can alsobe used.

Work platforms are often included as part of the formwork, especially at the edge ofslabs. The figure below shows a work platform constructed next to the edge beam of aslab. Note that it does not show a toe board which is required in order to meet therequirements of AS 1657.

Figure 22 ANCHORAGE OF TALL PLATFORMS

Figure 23 WORK PLATFORM CONSTRUCTEDALONGSIDE EDGE BEAM OF A SLAB

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SELF-CHECK

EXERCISE 8: PLATFORMS

Read the section carefully and find the words missing from the following sentences:

1. A tower designed not to be moved is said to be _______________.

2. Mobile towers and platforms are usually used for ___________ work.

3. Bracing is used so that a tower remains __________.

4. Tie ropes are attached to ____________ points.

5. Tie ropes are set at an angle of ______________ from the ground.

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SUMMARY

So far you have covered the information required to complete Assessment Task 1. Theknowledge you have gained so far will be used each time you begin work on a buildingsite. The importance of this information will become more evident when you beginwork on various sites.

Self-check exercises in this package are on yellow pages. This exercise has beendesigned to test your understanding of the information you have covered so far.

Answers to the self-check exercises are on the blue pages at the end of the package.

You may find it useful to make your own brief summary below on the following topics:

Formwork Member Sizes and Spacings:

Falsework Member Sizes and Spacings:

Loads on Formwork:

Use of Tables and Graphs to Design Formwork:

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Drop Panels and Hopper Heads:

Construction Workers’ Duties:

Quality Control Procedures:

Working Drawings:

Calculation of Material Quantities:

Working Platforms for Walls and Columns:

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SECTION 2 - SETTING OUT, CONSTRUCTING AND ASSEMBLINGFALSEWORK AND FORMWORK

READ

INTRODUCTION

This section of this package deals with two main aspects:

• set out falsework and formwork; and• construct and assemble falsework and formwork.

These areas contain essential information you will need to partly complete AssessmentTask 2 which addresses learning outcome 2:

Set out, construct and assemble formwork.

The information relating to set out and construct formwork will be presented under fourtopics:

• Setting Out Falsework and Formwork• Constructing Falsework and Formwork for a Suspended Slab and

Beams• Locate, Construct and Fix Lift and Service Penetrations• Stairs and Landings

1. SETTING OUT FALSEWORK AND FORMWORK

Before formwork and falsework are commenced a job has to be set or marked out. Thisis done using:

• centre lines;• off sets;• grids;• datums; and• reduced levels.

A centre line is a line across the centre of a project. Measurements are made from thiscentre line. The measurements are not made from an external side or what is called aface.

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A datum or datum point is a reference point used in measuring. Distances, in otherwords, are calculated from a datum. A datum can be horizontal or vertical and will befixed or immoveable.

Vertical datums are set with reference to sea level and what are known as theAustralian Height Datum (AHD). The AHD will be marked at the commencement ofthe job by a land surveyor.

Reduced levels are height levels expressed in terms of relation to AHD. Heights on astructure or a building are measured from an AHD. They are not necessarily measuredfrom ground level.

The surveyor will also mark horizontal datums which are measured from grids orcoordinates of longitude and latitude. These coordinates are recorded as the AustralianGrid System or AGS.

Grids are used, too, in working drawings. The drawings are over a grid with linesmarked with numbers and letters just as in a suburban road map. Points in a project canbe identified using the grid. A column, for instance, might be set at F5 while a towermay be located at D7.

Figure 24 CENTRE LINE

Figure 25 GRID LINES USEDTO SHOW LOCATIONS

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SELF-CHECK

EXERCISE 9: SETTING OUT

Give a brief explanation of each of the following:

1. Centre line

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2. Datum

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

3. AHD

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

4. AGS

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

5. Coordinates

_____________________________________________________________________

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2. CONSTRUCTING FALSEWORK AND FORMWORK FOR ASUSPENDED SLAB AND BEAMS

Slabs and beams are usually constructed together. The beams add strength to the slab.Therefore the formwork for a slab is often constructed at the same time as theformwork for beams. Usually a slab will have an edge beam and internal beams. Theformwork and falsework for these is different.

Formwork for a beam is usually supported by a soffit form. Soffit forms are those usedfor the underside of concrete structures like slabs and beams. Generally soffit forms aredesigned to be level or near level. They will always incorporate safety rails for workers.

Generally a small section of a soffit form will be completed. This section will then beused as a base for further work with tools and equipment stored on the section that iscompleted first.

The formwork for beams and slabs is commonly constructed using plywood. The beamhowever is usually less wide than the sheet of plywood. The plywood can be cut to fitbut this means that the plywood might not be reusable and some will be wasted. Foreconomy, the plywood is not cut. Instead, the formwork is built up on a whole sheet ofply which can then be reused.

The formwork for edge beams usually includes a work platform which is cantileveredoff the edge of the beam. This is unsafe if it is not properly supported and could distortthe formwork. There is more than one way of supporting the work platform. If theformwork can be extended to include the platform, that may be safe enough butsometimes that cannot be done. Extra props might be needed as shown in Figure 27.

Figure 26 SLABS AND BEAMS

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Beam Forms

Beams are deeper and heavier than the surrounding slab. Therefore the pressure of theconcrete will be greater as it is poured. This will tend to push the sides of the beamforms out of shape. The formwork has to be strong at the bottom edges and it must beconstructed so that it resists tipping over as the concrete is poured. Beam forms mustbe correctly supported by props widely spaced. An unstable design can be improved bymoving the supports beyond the edges of the beam.

Figure 27 WORK PLATFORM AT EDGE OFSLAB SUPPORTED BY PROPS

Figure 28 BEAM SUPPORTS IN THIS EXAMPLEALLOW DANGEROUS UNBALANCE TO EXIST

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The detail of formwork can also include features which make stripping easy (astripping band, Figure 30, and tolerance gap, Figure 31).

Figure 29 THE PROBLEM OF ECCENTRICITY ISAVOIDED IF THE LOAD IS ALWAYS INSIDE THESUPPORTS

Figure 30 STRIPPING BAND AT BEAM SIDEALLOWS SLAB SOFFIT TO BE STRIPPED WITHOUTDISTURBING THE BEAM

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Deep beams need ties to hold the sides in place. Typical beam formwork with ties areshown below.

Figure 31 TOLERANCE GAP WITH CLOSURE ANGLEAT BEAM SIDE ALLOWS EASY STRIPPING OF BEAM SIDEWITHOUT DISTURBING SOFFITS

Figure 32 TYPICAL DEEP BEAM FORMWORK WITH TIES

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Figure 33 TYPICAL DEEP EDGE BEAMFORMWORK SHOWING TIES AND THE USE OFSPREADER BAR AND STRUT TO KEEP THE BEAMPLUMB

Figure 34 TYPICAL TIES ARE THE ‘HE BOLT’ SYSTEM

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Soffit form construction proceeds in three stages -- the formwork construction stage,the pouring stage and the strengthening stage.

At the formwork construction stage the major problem lies with keeping the soffitrigid. This is particularly important with high level forms which can be subject tostrong wind forces. To deal with these strong wind forces soffit forms can be tied withguy ropes. Supporting scaffolds are also braced.

The pouring stage is when the soffit form must bear its heaviest load. This load shouldnot be increased by mounding – that is allowing a mound of concrete to be gathered ina small area (Figure 35).

Extra stress on a form can also be caused by allowing buckets to swing against thestructure.

Every care MUST be taken to avoid mounding and heavy contact from swingingbuckets. Both of these can cause serious damage to a form.

At the strengthening stage the concrete gradually becomes able to support itself andother loads and structures.

Loads that bear down on the newly laid slab or beam will include:

• self weight;• construction activity ;• concrete;• materials;• mounded concrete; and• impact.

Figure 35 THE EFFECTS OF MOUNDING

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Each of these loads is accounted for in design of the formwork. AS 3610 providesstandard figures for some of them. The concrete pressure is dependent on the thicknessof the concrete.

Forces that will cause lateral or sideways load or stress will include:

• wind;• construction activity;• impact; and• water.

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SELF-CHECK

EXERCISE 10: SLAB AND BEAM FORMWORK

Prepare rough sketches with appropriate notes to explain the following:

1. Soffit form

2. Mounding

3. Guy ropes

4. Scaffold bracing

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3 LOCATE, CONSTRUCT AND FIX LIFT AND SERVICEPENETRATIONS

In constructing slabs and beams allowance must be made for what are known aspenetrations which are, in fact, holes left in a structure for pipes, stairwells, lift wellsand so on. These are marked on the working drawings and located from drawing gridreferences.

Formwork is constructed so that concrete will not cover a penetration. This is donesimply by forming edges around where the penetration is to be located. Edges are oftenmade from plywood braced with metal or timber. For small penetrations plastic foam orplastic tubes canbe used. The figure below shows what they might look like.

Figure 36 TYPICAL PENETRATIONS

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Larger, rectangular penetrations can be made from plywood as shown below.Overlapping like this makes stripping or removal easier.

Figure 37 STRUCTURE OF RECTANGULARPENETRATION

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SELF-CHECK

EXERCISE 11: SERVICE PENETRATIONS

Write TRUE or FALSE after each of these sentences:

(a) A penetration is a place in a beam or slab where concrete is laid.____________

(b) Penetrations are located from working drawings from grid points.

____________

(c) Edges of penetrations in formwork are always constructed from

wood._________

(d) Plywood forms are always braced with timber.__________

(e) Timber penetration forms have overlapped edges so they can be dismantled

easily.___________

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4. STAIRS AND LANDINGS

Stairs can be cast off site and placed in position or cast on site. Formwork must beconstructed for the soffit, the sides of the stair and the risers. The detail of riser formsand sides is shown below.

The soffit to the stair must be propped adequately. One method of propping is shownbelow.

Figure 38 DETAIL OF STAIR FORMS

Figure 39 DETAIL OF WHOLE STAIRCASE

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SUMMARY

In this section of Formwork - Suspended Slab and Beam you have covered:

• set out and construction of falsework and formwork• location of lift and service penetrations

A practical activity at the end of Section 3 will cover:

• set out, fabrication and erection of slab and beam formwork; and• stripping, cleaning and storing formwork and falsework.

Before progressing to Section 3, you may like to make some notes on the followingtopics covered in this section:

Setting Out Falsework and Formwork:

Constructing Falsework and Formwork for a Suspended Slab and Beams:

Locate, Construct and Fix Lift and Service Penetrations:

Stairs and Landings:

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SECTION 3 - STRIPPING, CLEANING AND STORING FORMWORKAND FALSEWORK

READ

INTRODUCTION

In this final section of Formwork - Suspended Slabs and Beams, you will coverstripping, cleaning and storing formwork and falsework

These areas contain the essential information you will need to complete AssessmentTask 2 which addresses learning outcome 3:

Strip, clean and store formwork and falsework.

The information covered will be presented under four topics:

• Stripping Formwork• Stripping Sequence and Equipment Removal• Backing off of False\work and Adjustment Hardware• Removal, Denailing, Cleaning and Storing of Formwork

1. STRIPPING FORMWORK

The stripping or ‘striking’ of formwork can only be done when concrete is able tosupport itself and the loads that are to be placed on it. As stripping or striking takesplace, the entire weight of the concrete and the structure transfers to the concrete.

As McAdam points out: “The general rule in stripping is that it will be done so there isno thermal or physical shock, and there shall be a gradual transfer of the load.”

What this means is that stripping should be avoided if extreme weather changes areexpected and on days that are expected to be either extremely hot or extremely cold.Stripping should take place without knocks or jolts. It should also be done so suddentransfers of load don’t happen.

One way of protecting the concrete from shock is to remove some of the formwork butleave the props in place. This is especially important for the stripping of beams, whichare heavier than slabs. After the formwork is removed from a beam the props can beput back, or preferably, the formwork is designed so that the props stay in place withoutbeing moved.

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Special props can be used, which have collars to support the formwork beams as wellas platforms to bear directly on the plywood. With these props in place the beams canbe dropped and the plywood removed without moving the props. Figure 40 shows thedetail of this kind of setup.

The time for removing formwork is set out in AS 1509 but on the job no formworkmay be removed without the written permission of the site engineer.

The minimum periods for striking formwork used with Portland cement are as follows:

Formwork Surface temperature of concrete

16º C 7º C

Vertical forms to columns,walls and large beams

12 hours 18 hours

Slab soffits 4 days 6 daysBeam soffits (beams leftunder)

10 days 15 days

Props to slabsProps to beams

10 days14 days

15 days21 days

Note carefully that the colder the weather, the longer the formwork must stay inposition.

In general slabs, as the table indicates, will be stripped before beams. Because beamsare heavier than slabs, they may cause the slab to bend, therefore it is better to strip theslab first, then the beam.

Figure 40 FORMWORK INCORPORATING PROPS WITH COLLARSTO STRIP WITHOUT REMOVING PROPS

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• Checking plans and specifications for stripping times

The conditions to be met for stripping will be written out by the design engineer for theproject.

Documentation or written instructions should specify:

• concrete age and minimum strength at time of stripping;• the effectiveness with which the curing procedures are carried out;• limits on the loads that can be placed on the structure; and• the method and order of stripping.

Figure 41 UNDESIRABLE DISTORTION OF SLAB LIKELYWHEN BEAMS ARE STRIPPED FIRST

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2. STRIPPING SEQUENCE AND EQUIPMENT REMOVAL

Stripping is usually a two stage process.

The first or preliminary stage, involves removing the relatively short spans between theprops, and can usually be done well before the development of the full concretestrength.

The second or final stage is the removal of all remaining formwork.

• Backpropping

Sometimes in stripping sections of formwork backpropping is used. Backproppinginvolves using a jack or other support under a beam or slab after the formwork has beenremoved.

Stripping plywood and timber formwork takes place in the following sequence:

1. The soffit framing is lowered 50 mm or more.

2. The plywood and metal edging strips will come down.

3. The joists can then be lowered onto beams.

4. The plywood can now be fully removed by sliding it out from the edges of theform

Figure 42 THE BACKPROPPING PROCEDURE

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5. The joists are then removed

6. The bearers are removed – taking care particularly with telescopic steel postswhich by now will have become unstable and potentially dangerous.

Note that in following this procedure care should be taken to protect plywood and othertimbers from falls. These can either smash the timbers or cause damage that may behard to detect but may cause difficulties when the timber is used on a new project.

• Reshoring

Reshoring is simple - all the formwork and falsework is removed and then props arereplaced at specified spacings. These are called reshores and they protect the uncuredconcrete from damage. This method is not preferred when large beams and slabs areinvolved. Reshoring is usually carried out on small sections at a time.

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3. BACKING OFF OF FALSEWORK AND ADJUSTMENT HARDWARE

A number of metal appliances are used in formwork. These include what is known asadjustment hardware.

Invariably adjustment hardware is built so that it can be adjusted for fitting andremoval. Sometimes it is made from aluminium and often it is made from steel.Removing adjustment hardware is generally a matter involving unbolting or unlockingrotary locks.

Adjustment hardware must be backed off, (that is loosened) and removed, givingattention to the rules that apply for other stripping. In other words, backing off andstripping must be done in such a way as to avoid shocks and sudden transfers of load,and to make sure that as little damage as possible occurs to the equipment.

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4. REMOVAL, DENAILING, CLEANING AND STORING OFFORMWORK

Release agents are painted on to formwork so that it will move away easily from thecompleted concrete surface. Different kinds of formwork require different kinds ofrelease agent and it is important to see that the correct release agent is used.

It is also important to make sure that the release agent that is used does not contaminatethe reinforcement.

Some release agent types are shown in the table below, adapted from Fletcher andLavan.

Release Agent Type Comments

Neat oil with surfactant A useful general purpose release agent for allkinds of formwork, including steel. Overapplication may result in the staining of theconcrete. Oil film may be affected by heavyrain.

Mould cream emulsion (oil phased) Widely used agent recommended for allformwork except steel. Especiallyrecommended for use with timber. Suitablefor high quality finishes. Storage life may belimited.

Chemical release agent For use with all kinds of formwork. Suitablefor high-quality finishes. Resistant to washingoff by rain. Safer to walk on than oily film andwill not be carried on shoes from theformwork onto concrete. Coverage greaterthan for oils. Expensive if not used carefully.

Wax Recommended for moulds made of concrete.Difficult to apply evenly.

Barrier paint Becomes scratched. Needs to be used with arelease agent.

Neat oil (without surfactant) Not to be used where appearance is important;encourages the use of blowholes. Inexpensive.Can be used where concrete is later to becovered.

Water-phased emulsion (oil-in-water) Not to be used for visual concrete. Causessevere retardation and discolouration. Cheapand easy to apply. Can be used if concrete isnot exposed to view.

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Some formwork components such as the cardboard forms used especially under floorslabs are not destined for re-use or recovery. Most formwork components, however,can be removed, cleaned and stored for re-use.

As soon as the formwork has been struck, it should be cleaned to remove grout anddust. In the case of steel forms these should also be lightly oiled before storage.

With all wooden form components it is essential to remove all nails. Unremoved nailscan be extremely dangerous to workers. As they rust they can damage timber. They canalso cause fitting difficulties when being used in new forms.With nails removed, formwork must be cleaned thoroughly generally using water andheavy brooms. Metal components must also have all dirt and traces of concreteremoved.

For storage, all formwork components need to be dry and properly waterproofed. Steeland iron components should be lightly oiled. Plywood can be treated with sealingcompounds. Storage should be in weatherproof sheds or containers.

Panels and plywood sheets should be stored horizontally on a flat level base. Largepanels are best stored vertically with the concrete faces together. Soldiers and waling,which are loose, are best stored in boxes or drums.

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SUMMARY

You now have the necessary information to complete the Practical Activity 3 whichrelates to Assessment Task 2.

Self-check exercises in this package are on yellow pages. This exercise has beendesigned to test your understanding of the information you have covered so far.

Answers to the self-check exercises are on the blue pages at the end of the package.

You may find it useful to make your own brief summary below on the following topics:

Stripping Formwork:

Stripping Sequence and Equipment Removal:

Backing Off of Falsework and Adjustment Hardware:

Removal, Denailing, Cleaning And Storing of Falsework, Formwork and RelatedEquipment:

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SELF-CHECK

EXERCISE 12: STRIPPING, CLEANING AND STORING

Write brief notes to explain what is meant by each of these. Add sketches where youthink they are necessary:

1. Backpropping

2. Backing off

3. Release agents

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PRACTICALACTIVITY

ACTIVITY 3: ERECT AND STRIP FORMWORK

To carry out this activity, you will need a partner to assist you in the construction,erection stripping and handling of the falsework and formwork.

All work must be carried out according to the criteria and tolerances specified inAssessment Task 2 on pages 16 and 17 and AS 3610.

1. SET OUT, FABRICATE AND ERECT FORMWORK

Set out, fabricate and position formwork for a reinforced concrete suspended slab, withintersecting and perimeter beams, that encompasses the following specifications:

• A minimum slab size of 6000mm long x 6000mm wide x 300mmthick.

• Intersecting and perimeter beams, minimum end section size 300mmwide x 400mm deep or similar.

• Soffit height minimum two unit frames from floor datum point.• Perimeter working platform - minimum 450mm wide.

NOTE: All tolerances are to comply to AS 3610 or those specified on the plansand specifications for the project. Specifically concrete surfacedeflection ± 3mm and formwork member position ± 10mm.

2. STRIP, CLEAN AND STORE FORMWORK AND FALSEWORK

The structure is to be dismantled to demonstrate safe and effective stripping and storingprocedures.

1. Falsework and adjustment hardware are backed off to allow ease of stripping.

2. Falsework and formwork is safely and sequentially removed, denailed, cleanedand stored.

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CONCLUSION

This learning package has combined the theoretical and practical components for themodule CCC348 Formwork - Suspended Slab and Beam.

Having successfully completed the requirements of this module, you now understand:

• applying the principles of formwork in the design, planning andquality control;

• setting out, constructing and assembling formwork; and• stripping, cleaning and storing falsework and formwork.

You can expect to apply your knowledge and skills again and again on a range ofbuilding sites.

Those who developed this package hope that you have found its style and preparationeasy to use.

Congratulations you have successfully completed the Module CCC348 Formwork - Suspended Slab and Beam

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SELF-CHECK ANSWERS

EXERCISE 1: FORMWORK CALCULATIONS

1. Calculate the concrete load due to a slab 250 mm thick.

__________________________________________________________________ 6.25 kPa

2. Assume that the slab is to be suspended by formwork and props. Calculate thetotal load on the props due to the formwork, live loads, concrete and stackedmaterials.

_________________________________________________________________14.35 kPa

EXERCISE 2: FALSEWORK

1. What is falsework?

Falsework is support for concrete forms. The name is particularly used inbridge and harbour work and longer construction work.

2. What materials are used for the construction of falsework?

Falsework is constructed from timber, ply and various kinds of metals andfabricated metal components.

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SELF-CHECK ANSWERS

EXERCISE 3: CAPITALS AND COLUMNS

1. What is a capital?

A capital is the top part of a column.

2. What are the usual shapes of columns?

________Cross-sections across columns may be square, rectangular, circular and oval.

3. Make a sketch of a hopper head.

Sketch._________________________________________ Show your instructor for verification.

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SELF-CHECK ANSWERS

EXERCISE 4: CONCRETE WORKERS DUTIES

(a) Before a concrete pour

(b) During a concrete pour

(c) At the completion of a concrete pour

ChartAnswers should stress efficiency and safety.Show your instructor for verification.

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SELF-CHECK ANSWERS

EXERCISE 5: QUALITY

Write TRUE or FALSE after each of these statements:

1. Alignment is where the concrete is positioned False.

2. At the end of seven days concrete has reached its final strength False.

3. Concrete is usually tested at the end of ten days and at the end of sixty days

False.

4. Concrete for testing is taken in sample cores True.

5. Sample cores are often taken earlier on large jobs True.

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CCC348 Formwork - Suspended Slab Beam SECTION 1


SELF-CHECK ANSWERS

EXERCISE 6: WORKING DRAWINGS

From Figure 15, identify the following:

1. slab area

2. perimeter beam

3. intersecting beams

You should be able to draw working drawings for formwork. This will be checked byyour instructor.

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SELF-CHECK ANSWERS

EXERCISE 7: CONCRETE CALCULATIONS

1. Calculate the amounts of concrete required for these slabs:

7m x 12m x 300mm = 25.2 m3

8m x 20m x 250mm = 40 m3

15m x 30m x 500mm = 225 m3

2. Calculate the concrete required for these columns:

6m high x 1m in diameter = 4.72m3

4m high x 600mm in diameter = 1.13m3

10m high x 2m in diameter = 31.42m3

EXERCISE 8: PLATFORMS

Read the section carefully and find the words missing from the following sentences:

1. A tower designed not to be moved is said to be Static.

2. Mobile towers and platforms are usually used for Light work.

3. Bracing is used so that a tower remains Rigid.

4. Tie ropes are attached to Anchorage points.

5. Tie ropes are set at an angle of 45º from the ground.

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SELF-CHECK ANSWERS

EXERCISE 9: SETTING OUT

Give a brief explanation of each of the following:

1. Centre line

____________A centre line is a line drawn through the centre of a proposed structure.

2. Datum

____________________________________________A datum is any set point in height.

3. AHD

________________________________________AHD means Australian Height Datum.

4. AGS

___________________________________________AGS is the Australian Grid System.

5. Coordinates

Coordinates are grid lines.��

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SELF-CHECK ANSWERS

EXERCISE 10: SLAB AND BEAM FORMWORK

Prepare rough sketches with appropriate notes to explain the following:

1. Soffit form See Figures 31, 32 and 38

2. Mounding See Figure 35

3. Guy ropes See Figure 22

4. Scaffold bracing See Figure 23

See your instructor for verification.

EXERCISE 11: SERVICE PENETRATIONS

a. A penetration is a place in a beam or slab where concrete is laid.False

b. Penetrations are located from working drawings from grid points.True

c. Edges of penetrations in formwork are always constructed from wood.False

d. Plywood forms are always braced with timber. False

e. Timber penetration forms have overlapped edges so they can be dismantledeasily. True

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SELF-CHECK ANSWERS

EXERCISE 12: STRIPPING, CLEANING AND STORING

1. Backpropping

Backpropping is propping slabs and beams after formwork has beenremoved.

2. Backing-off

Backing-off is loosening or adjusting hardware prior to strippingformwork.

3. Release agents

Release agents are chemicals applied to formwork components so they willmove away easily from set concrete.

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