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TEMPORARY WORKS : FORMWORK
Construction Practice 2
2012
Essential reading: Chudley & Greeno- Building
Construction Handbook; Pg 498-520
Exploiting the material qualities of concrete!
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Formwork : Content
Formwork refers to moulds that provides support for
wet concrete during construction
Learning Outcomes for this topic:
■
General requirements
■
Components and Hardware
■
Columns
■
Walls
■
Floor slabs
■
Beams
Ancillary Information (interest only)
■
Sliding Forms
■
Housing Kits
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Formwork & Falsework
Falsework

A framework or structure, of a temporary nature, for
the support of materials, equipment or a construction
assembly while it is not self supporting.
The main load-bearing members of falsework are
generally vertical (similar to Dead Shoring).
Formwork

A structure, usually of a temporary nature, used to
contain, mould and support poured concrete until it is
able to support itself.
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Formwork :
 Concepts and Terms:

Timber is the traditional formwork material with
plywood used for working faces, however a range
of other materials are also used
(Q. What is a major disadvantage of timber?)
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

Working faces that are fabricated as panels fixed
to a framework are known as ‘shutters’
Shutters are assembled, jointed and braced
together often with proprietary components and
fixings
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Formwork : Requirements
General requirements:





Must be strong enough to bear the weight of wet
concrete & reinforcing steel - plus all construction
loads without excessive deflection
Joints must be tight - to prevent loss of fine
material from concrete
Construction should be simple - in an order to
allow easy stripping (striking)
Must allow continuing vertical support while concrete
reaches design strength (at 14, 21 or 28 days)
Formwork face in contact with the concrete must
be capable of producing the required concrete
finish
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Formwork : Columns
Why are in-situ columns prevalent on NZ projects?
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Formwork : Columns
Assembly sequence
150
Clamp Table
500
Brace
500
350
350
250
Column
clamps
200
Side shutters
200
Kicker plate
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Formwork : Columns
 Components: (ACROW Proprietary systems)
Typical column assembly
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Multiple vertical modules with proprietary clamps
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Circular Columns: steel proprietary moulds by Doka
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Motorway Pylons: modular moulds with proprietary inserts
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Formwork : Walls
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Formwork : Walls
 Walls – assembly sequence
Walings
Tie rods/bolts
Braces
Shutters
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Formwork : Walls
 components:
ACROW Proprietary systems
Standard Shutters clamped together
Faces tied with Thru Bolts
Assembly braced with adjustable props
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Formwork : Walls
 Components:
ACROW Proprietary systems
 Shutter modules
weblink
300-900
Slotted Galvanised steel
frame faced with 14mm
plywood
300-900
Standard Formwork Shutters (also in external, internal and hinged corners)
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Formwork : Walls
 Components: (ACROW Proprietary systems)
 Soldier Beams
Soldier Beams
used as
strong-backs
and bracing
props
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Formwork : Components
 Hardware: (ACROW Proprietary systems)
 Tie Rods and Spacers
She Bolt
She Bolt is turned to remove, in two halves, with connector tie
rod left embedded in concrete
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Formwork : Components
 Hardware: (ACROW Proprietary systems)
 Tie Rods and Spacers
Snap Tie
End of snap tie is levered up & down
until it snaps at the breakback notch
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Formwork : Components
 Hardware: (ACROW Proprietary systems)
 Tie Rods and Spacers
Tie Rod
Coupler
PVC
Spacer
Tube
Thru Rod is
completely
removed
Thru Rod
PVC tube left in
place (??)
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Formwork : Components
 Components: (ACROW Proprietary systems)
 Propping Swivelling
head
Frame set (adjustable legs at top & base)
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Variable direction
Beam and joist
arrangements
Adjustable
Prop
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Formwork : Multiple Lifts
 Wall assembly sequence
Shutters
jumped to
next level
Waling
packer
Soldier beam
strong-back
Previously
poured wall
Soldier beam
brace
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Formwork : Walls
MoZular systems such as Framax consists of galvanised
steel or aluminium framing with 16mm Formply facings
(phenolic resin finish)
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Formwork : Walls




Timber make-up sections are fitted to create non-standard lengths
Ditto non-standard width stop ends as on right
Engaged columns are formed by stepped sections
Note double props and red handles for tightening thrubolts
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Formwork : Walls
Modular system allows forms to be pre-assembled using proprietory
clamps into large gangforms lifted into place by crane
This is major time-saving strategy for speeding up the pouring cycles
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Formwork : Walls
 Walls:
Proprietory Systems
with integral working
platforms
Dokaset Wall System
http://www.doka.com/doka/en_global/products/wall/framed/index.php
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Formwork : Walls
Striking of a large 5600h x 4200w
prefabricated gang form by crane
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Formwork : Walls
Flexible plastic inserts at corners allow cranked connections
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Formwork : Walls
Standard Semi-circular
Steel Forms jointed to
Flat sections
see Doka Hinged Form
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Formwork : Walls
8m high Reservoir walls poured in 2 lifts:
Large curved gang forms raised for second lift,
Note integral working platforms, lapped steel cages,
soldier beams bolted to first lift, raking shores bolted
to conc. pad bases
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Formwork : Shoring
Triangulated 350mm Soldier beams with swivel heads
used as raking shores –
why the many holes?
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Formwork : Shoring
If the opposite side is inaccessible, framed
shoring offers a reusable option – i.e. retaining walls
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Formwork : Floors
Apartment block formwork: Hong Kong
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Formwork : Floors
Soffit
shutters
 Floors:
Joists
Assembly
Sequence
Formply
Soldier beam
Props
Bracing
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Formwork : Floors
 Floor Panels: (ACROW Proprietary systems)
Aluminium Panel Shutters for propped soffit formwork,
note locating pins on prop head – striking sequence?
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Formwork : Floors
Form-ply formwork offers a working platforms for steel fixing
Lowered sections are for wide but shallow beams – why shallow?
Note starter bars projecting from column heads – what’s missing?
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Formwork : Floors
Steel fix and services – teams working against the clock!
How many trades are involved simultaneously here?
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Note sequence of construction
above
Doka proprietory floor
and beam system
Coated (yellow) formply
panels with sealing edges
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Formwork : Floors
Large flat slab (no beams) and a square column
grid – what type of structure is to follow?
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Formwork : Floors
Curved forms tend to cost a bit more –
Can you see why?
No edge beams = post-tensioned: yes or no?
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Formwork : Floors
How do we prop this job?
Sketch a cross section to explain the method
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Formwork : Floors
You can see what is to come here: intersecting vaults
How will you construct the double curved formwork?
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Formwork : Floors
Oriental Plaza: Design-Build project by Hawkins Construction
Retail along edges and 6 level Park Garage
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First slab
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Formwork :
Flying Tables
see youtube clip
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Formwork : Beams
 Edge Beam/Floor
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Formwork : Beams
 Beam/Floor
Soffit decking
Soffit framing
Bearer
Side shutters
Tie bolt
Soffit former
Joists & Blocking
Crosshead
Brace
Props
Proprietary
Beam Clamps
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Formwork : Edge Beams
 Edge Beam/Floor
Soffit decking
Brace
Soffit framing
Side shutters
Soffit former
Joists & blocking
Crosstree
Joist/prop
Braces
Prop
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Edge Beam:
Ply formwork detail
constructed on site
Question:
Is early striking of
sides possible without
disturbing the props?
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Doka System for edge beams – striking sequence?
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Doka System: shoring method
Why no cross bracing here?
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Formwork : Sliding
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Formwork : Sliding
Formwork
 Walls – Sliding Formwork
Website link to animation:
http://www.interform.as/website.aspx?displayid=3602
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Formwork : Sliding
 Walls: Multiple lift Jump-Form
 Lifted by crane
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Screwjack selfclimbing platform
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Formwork : Sliding
 Walls: Multiple lift Jump-Form
 Self Climbing
(Hydraulic rams)
Bearing Foot
supports jump
form while
lifting beam is
trailing
Internal face of core before
internal shutters jacked up into
place
Hydraulic ram lifting
jump form against
fixed lifting beam
Refer: Raymond Wong Wai Man, City University Hong Kong
Lifting beam
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Formwork : Sliding
 Walls: Multiple lift Jump-Form
 Self Climbing
(Ratchet jacks)
Refer: Raymond Wong Wai Man, City University Hong Kong
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Formwork : Sliding Case Studies
Sample page ex
website
http://www.cityu.edu.hk/CIVCAL/book/misc_advanced.html
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Formwork : Facade Systems
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Doka facade system:
Jump Form that engages via facade apertures
What about the columns?
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Formwork : Sliding
 Walls: Multiple lift Jump-Form (Auckland Sky Tower, 1997)
‘Dry Wall’ in front of
piled retaining wall
3m thick pad with
12/600Ø X 20m
deep piles under
600m³ of concrete
Formwork for
Elevator shaft pit
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Formwork : Sliding
 Walls: Multiple lift Jump-Form (Auckland Sky Tower, 1997)
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Formwork : Housing Kits
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Formwork : Housing Kits
See video clip of in-situ apartment block = youtube + wallties co
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Formwork : Housing Kits
Textured formliners used to create masonry look
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Formwork : Pools
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Sample extract 1:
(“Formwork for Concrete”)
Diagrams of the 4 basic Formwork
Types and indicating the specific
components of each
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Sample extract 2:
(“Formwork for Concrete”)
A listing in table 14.1 of 8 performance
requirements for formwork, with a brief
discussion of each requirement
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Beam Box: note detail of raking cut to ease striking
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Web Resources & Links:
Acrow Formwork Systems - New Zealand:
http://www.acrow.co.nz/Acrow+Formwork.html
Scaffolding Design Software Demo:
http://www.scaffolding.co.nz/shop/BUY/Scaffolding+Software.html
RMD Kwikform Articles:
http://formula.rmdkwikform.com/
Lansdowne Road Stadium images:
http://www.lrsdc.ie/gallery/photocategory.asp?PCID=34&NCID=0
Hong Kong CIVCAL videos:
http://www.cityu.edu.hk/CIVCAL/tour/AEB/video5.html
Wikimedia formwork images:
http://commons.wikimedia.org/wiki/Category:Formwork
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Formwork : Hybrids
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