Chapter 8 formwork Bách Khoa

Chapter 8. Concrete
formwork

Construction methods and management


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Chapter 8. Concrete
formwork
8.1 General requirements for formwork
8.2 Classification of formwork
8.3 Typical formwork (footing form, wall
form, column form, beam and slab form)
8.4 Shores and scaffolding
8.5 Concrete form design
8.6 Formwork inspection and acceptance

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Causes of failures of
formwork
• Improper or inadequate shoring
• Inadequate bracing of members
• Lack of control of rate of concrete
placement
• Improper vibration or consolidation

of concrete
• Improper or inadequate connections
• Improper or inadequate bearing
details
source: Peurifoy và Oberlender, 1996, tr.156

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Causes of failures of
formwork
•
•
•
•
•
•

Premature stripping of formwork
Errors in placement of reshoring
Improper or lack of design of formwork
Inadequate strength of form material
Failure to follow codes and standards
Modifications of vendor-supplied
equipment
• Negligence of workers or supervisors
source: Peurifoy và Oberlender, 1996, tr.156

©2010 của Đỗ Thị Xuân Lan , GVC. Ths.

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Chapter 8. Concrete formwork

GENERAL REQUIREMENTS FOR
FORMWORK
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Formwork/concrete life
cycle

source: Hanna, 1999

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Objectives in building and
designing formwork
• Quality— must be designed and built with
sufficient stiffness and accuracy so the
size, shape, position, and finish of the cast
concrete are attained within the required

tolerances.
• Safety— must be built with sufficient
strength and factors of safety so they are
capable of supporting all dead and live
loads without collapse or danger to workers
and to the concrete structure.
• Economy— must be built efficiently,
minimizing time and cost in the construction
process
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Principles in building and
designing formwork
Each component of the forms must be
able to support its load from two points
of view:
• Strength: based on the physical
properties of the material used
• Serviceability: the ability of the selected
sections to resist the anticipated loads
without exceeding deflection limits

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General requirements for
formwork
• Be strong enough to withstand the
pressure of plastic concrete and to
maintain their shape during the concrete
placing operation
• Be tight enough to prevent wet concrete
from leaking through joints and causing
unsightly fins and ridges
• Be simple to build
• Be easy to handle on the job
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General requirements for
formwork
• Form sections must be of a size that can be
lifted without too much difficulty and
transported from one job to another if
necessary
• Be made to fit and fasten together with
reasonable ease
• Be designed such that the form may be
removed without damage to the concrete or
to themselves
• Be made so that workers can handle them
with safety
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Chapter 8. Concrete formwork

CLASSIFICATION OF
FORMWORK
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Formwork classification

Formwork
classification

The material
used

The structural
component
molded

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The way of using

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Formwork classification

The
material
used

•
•
•
•
•
•
•

Lumber
Plywood ,
Steel,
Aluminum
Steel-framed plywood panel
Plastic,
Concrete, brick …

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Formwork classification

Brick form

Source: HCMUT student

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Formwork classification
Steel-framed plywood panel
Plastic

source:

Source: HCMUT student

Plywood

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Formwork classification

Source: HCMUT student

Steel

source: doosong vina

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Aluminum
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Formwork classification

catio

Plywood and lumber
Source: HCMUT student

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Formwork classification
Wood

Metal

Aluminum

Plastic(FUVI)

5 – 10 times

20 – 50 times

Over 100 times

Over 100 times

Surface quality

Good , degrades
rapidly

Good, degrades (rust
& deformation)

Excellent

Excellent

Weight/manage
ability

Average(10 kg/m²)

Heavy(+/- 31kg/m²)

Lightweight
(+/- 20kg/m²)

Very lightweight

(7kg/m²)

Average

Dangerous

Good

Excellent

Maintenance
cost

N/A

High

Average

Low

Recyclability

Cannot be recycledwasteful and difficult
to dispose of

Limited

At least 20%

At least 20%

Store inwarehouse
to prevent
weathering

Store inwarehouse to
prevent weathering

Store inwarehouse
to prevent
weathering

No warehouse
required

Specification
Reusability

Safety

Storage

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source: />

Formwork classification

•
The
•
structural
component •
molded
•
•

Forms for beams
Forms for floor slabs
Forms for walls
Forms for columns
Forms for footings

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Formwork classification

The
way of
using

•
•
•
•

•
•
•

Built-in-place forms
Prefabricated panel systems
Slip forms
Jump forms and Climbing forms
Travelling forms
Flying deck forms
Formwork for architectural concrete

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Built-in-place forms

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Prefabricated panel
systems

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Formwork for architectural
concrete

source: />
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Travelling forms
Travelling
forms
were
used at
Dong Nai
2 Brigde
Project by
CC1

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