CARPENTRY - Unitec

Unit 24363 Suspended Concrete Floor Systems
BUILDING TECHNOLOGY
CARPENTRY
THEORY UNIT 24363
Suspended Concrete Floors
LEVEL 4 CREDIT 2
Purpose
People credited with this unit standard are able to
demonstrate knowledge of proprietary suspended
concrete floor systems.
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Unit 24363 Suspended Concrete Floor Systems
Legislation relevant to this unit standard includes: Health and Safety in
Employment Act 1992 and Health and Safety in Employment
Regulations 1995; Building Act 2004;
Resource Management Act 1991; New Zealand Building Code;
NZS 3109 Concrete construction, available from Standards NZ
(http://www.standards.co.nz).
Demonstrate knowledge of proprietary suspended concrete floor systems.
Range
pre cast systems – hollow core, pre cast beams with timber infill,
flat slab, beam and slab;
permanent formwork.
1.1 Proprietary suspended concrete floor systems are identified and
described in terms of purpose, components and differences
between types.
1.2 Proprietary suspended concrete floor systems are identified in
terms of their location and purpose in a building.
1.3 On site delivery, cranage, storage and protection of proprietary
suspended concrete floor systems is described in accordance with
manufacturer’s specifications.
1.4 Placing and fixing of proprietary suspended concrete floor systems
to manufacturer’s specifications are described.
1.5 Formation of formwork for edges, joints and penetrations to
manufacturer’s specifications is described.
1.6 Placing and setting out of reinforcing for concrete topping to
manufacturer’s specifications are described.
1.7 Procedures for maintaining health and safety requirements when
setting up and dismantling proprietary suspended concrete floor
systems are described.
Range
work methods, plant, equipment, identification of
hazards and controls.
References:
www.cca.org.nz/shop/downloads/IB76.pdf
video.bobvila.com/m/21320441/stem-walls-slab-and-reinforcement-forconcrete-walls.htm
www.sitesafe.org.nz/siteSafePDFs/Falsework_Training_Module_Aug_
2002.pdf
www.migua.com Jointing systems
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Unit 24363 Suspended Concrete Floor Systems
Introduction
In NZ the vast majority of suspended floors are constructed in precast,
prestressed concrete.
Advantages over traditional flooring systems include:
Are manufactured in a quality controlled environment off site.
Engineer designed.
Quicker building time as the members can be manufactured at the
same time as on-site activities.
Long floor spans can be achieved.
May be used with other structural systems- masonry, steel, tilt-slab,
etc.
Co-ordinated on-time delivery. Craned into position from the delivery
trucks
Less labour on site, less congestion on site, less risk to the
environmental.
Pre-cast concrete flooring systems
Flat Slab.
Spans up to 6- 8 metres can be achieved.
75mm seating required.
75mm reinforced concrete slab as base.
75mm topping placed on top once in position and all other reinforcing,
ducting, etc is in place.
1.2m to 2.4m wide sections.
Temporary propping required.
Instant working platform provided once in place.
Excellent fire rating.
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Unit 24363 Suspended Concrete Floor Systems
Rib with Timber Infills
150- 200mm wide precast concrete ribs spaced at 800- 900mm
Timber boards filling in the span between them
Tied together with reinforcing and concrete topping
Temporary propping used until the top poured concrete is able to take
the weight.
Hollowcore
200, 300, 400mm thick hollow- to reduce self weight- precast concrete
May span up to 12meters
Ready made working platform- laid side by side
Propping not usually required
Reinforcing and concrete poured over the top to bind it all together
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Unit 24363 Suspended Concrete Floor Systems
Spaced Hollowcore
Similar to normal Hollowcore except the panels are spread out
Timber inserts placed between the panels
More economical
May require propping
Shell Beam
Precast concrete “U” shaped beams spaced at centres
Reinforcing placed and concrete is poured into them binding the floor
with the beams
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Unit 24363 Suspended Concrete Floor Systems
Double Tee
Photos taken inside the
Wilco Precast concrete factory at 66 Boundary Rd, Papakura,
with permission from Philip Archer, May 2009.
Cast as one then butted up to the next one
200- 600mm deep
May span up to 19m
Reinforced concrete topping cast over the top to bind it all together
2.4m wide but may come in at 1.2- 3.0m wide depending on
Manufacturer
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Unit 24363 Suspended Concrete Floor Systems
Table showing Fire Resistant Rating (FFR), Sound Transmission
Class (STC) and Impact Insulation Class (IIC)
These are rough guides as extra floor coverings, insulation, ceilings etc, will
effect these figures.
Table 2 shows a summary of the benefits of using Precast Concrete Floors.
Taken from: www.cca.org.nz/shop/downloads/IB76.pdf
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Unit 24363 Suspended Concrete Floor Systems
Handling
Site access must be as close to the building structure as possible to
avoid double handling. From truck to insitu, is ideal.
The heavier the unit- the bigger the truck and crane required. It pays to
ensure that the crane is well able to handle the maximum load required
of it.
Sections of the road may need to be cordoned off during delivery. A
Traffic Management Plan may well be needed if normal traffic is
affected during delivery.
Goods should be inspected while on the truck or before delivery in the
yard or during placement.
Ensure at no stage of the craning operation, anybody is under the load.
Tag lines and communication devices may be required to help coordinate
safe transition.
All propping must be in place before the Units are placed. Keep an eye
on the loaded structure during placement.
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Unit 24363 Suspended Concrete Floor Systems
Some details taken from:
/www.cca.org.nz/shop/downloads/ResidentialConcrete.pdf
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Unit 24363 Suspended Concrete Floor Systems
www.layher.co.nz/assets/brochures/layher_propping.pdf
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Unit 24363 Suspended Concrete Floor Systems
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Unit 24363 Suspended Concrete Floor Systems
An example from:
www.sitesafe.org.nz/siteSafePDFs/Falsework_Training_Module
_Aug_2002.pdf
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Unit 24363 Suspended Concrete Floor Systems
WORK SHEET 1
1. In the spaces provided sketch and label the following:
a. Ribs with timber infills
b. Hollowcore
c. Shell beam
d. Double Tee
e. Spaced Hollowcore
2. Outline procedures to maintain Health and Safety on a construction site
where the crane is placing a Shell Beam into position.
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3. What do the following abbreviations stand for and briefly describe what
is meant by each one:
a. FRR
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b. STC
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Unit 24363 Suspended Concrete Floor Systems
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c. IIC
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4. Using sketches and labels show the proper way of installing the
following:
a. Bottom end of a vertical Acrow Prop
b. Top end of the same prop supporting a temporary wooden beam
c. An angle prop supporting a high wall formwork.
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Unit 24363 Suspended Concrete Floor Systems
From: http://www.migua.com/d/25_75/brochures/25/migutrans.pdf Showing
one of many methods for joining floor areas to allow for
expansion and contraction.
Photos taken inside the Wilco Precast concrete factory at 66 Boundary Rd,
Papakura, with permission from Philip Archer, May 2009.
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Unit 24363 Suspended Concrete Floor Systems
Photos from CD “B” CD 11
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Unit 24363 Suspended Concrete Floor Systems
www.nziob.org.nz/index.php?page=gallery&file=139 Northern Motorway
extension- Johnson Tunnels
/www.agm.co.nz/images/pdfs/PB0209_Manukau.pdf Manukau Habour Bridge
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