Transcript CONSTRUCTION & STRUCTURES

Project 1
Hannah Merritt, Jacqueline Lyon, Thomas Andrews, Hayley Woda, Jessica Taylor
CONSTRUCTION SYSTEMS
*Portal frame
*Concrete construction
PORTAL FRAME
can be constructed from steel or timber
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The major advantage of this system is the
ability to span large distances; allowing
uninterrupted open spaces.
Steel is pre-fabricated (from universal
columns) erection is fairly easy, requiring
little skilled labour
It is therefore relatively inexpensive
However this system uses a large amount of
steel (in comparison to other systems)
although is not labour intensive so costs are
comparable.
The overall positives of using a portal frame
are inherent in its design principle, as they
use a rigid connection between the column
and rafter. This allows the bending moment
to be transferred, and also has a high
resistance to beam rotation.
Frame united, acting as one; with stress
therefore distributed throughout
Efficient structural solution to long spans
http://www.robertsonbuildings.com/products/frames/bracing/pframes/index.asp
Portal frames
• The portal frame itself can be divided in to 2 sections;
• Primary structure; columns (stanchion) & rafters.
Makes up the solid base of the frame
• Secondary structure; purlins & girts
ties together and unifies the primary structure, adding
strength also serving as bracing for the frame to an
extent.
Types of Portal frames
• Rigid base- doesn’t transfer bending,
bending occurs at ridge, knees & apex
• 2-pin portal-bending occurs at apex &
knees
• 3-pin portal-bending occurs at knees (not
apex or base)
Column & truss
• This structural system is similar to portal frame system,
the difference being that instead of using universal
sections for the rafters, it incorporates a truss system.
• This allows the overall mass of steel used to be kept to a
minimum; possibly proving cheaper.
• The truss system can be said to transfer loads better,
however, fabrication of the trusses is more labour
intensive.
Column & beam
• Beam and column construction
provides a simple means of
transmitting heavy floor loads
down to the foundations of the
building, either steel sections
or concrete and steel, usually
used in conjunction with a
composite floor.
• Positives are that you can work
on a clear grid system.
• This system also frees up the
walls for curtain walling
systems to take panels or
glass walling, easy installation
of composite floor.
This is an image of a timber portal frame showing the column and beam
structure
http://oak.arch.utas.edu.au/tbia/projsrch_rslt.asp?keyaspect+190
Timber portal frame
• Capability of spanning 50m
plus
• Two types of timber that can
be used for portal frame
construction are; Glue lam and
box beam
• Timber is not as elastic as
steel
• Can prove a cheaper
alternative (depending on
sizes and spans required.)
• May also perform better than
steel in the event of a fire
http://oak.arch.utas.edu.au/tbia/projsrch_rslt.asp?keyaspect=190
Rules of Thumb
Rules of Thumb for the Warehouse
Rules of Thumb
Slab/ footings
• A reinforced infill slab is appropriate for the warehouse, as it is
sturdy, robust & difficult to damage (and suitable for the moderately
reactive soil of the site)
• Low maintenance
• Good thermal properties
• Sound proof
• Good working platform (for forklift etc)
• Economical regarding both material and labour costs.
• Future floor plan alterations are difficult and expensive (due to
plumbing etc. located beneath slab)
• Ducted heating/cooling must be laid in ceiling (regarding office)
• Moisture proofing; weather penetration
• Structural damage also costly to repair
• Requires excavation- extra expense
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Flooring
• Using a metal deck like condeck or
bondeck and creating a reinforced
concrete floor is suitable for use in both
steel frame and concrete frame
construction.
• It is also a fire rated system
• Supplies a solid working surface and cover
for underneath.
Envelope systems (office)
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Aerated concrete panels;
Are also fire-rated
Allow easy design and installation
Lightweight; requiring little propping &
siteworks
• cheap
Roofing
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Steel sheet roofing;
Durable
Lightweight (although may also be a disadvantage)
Good fire resistance/ protection
Resistance to wind (uplift) and hail damage
Recyclability
Low maintenance
Wide color and profile choice
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Laserlight
May also be incorporated in the steel sheet roof (in sections or strips)
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Sisilation- used to prevent any water from gaining entry through the roof.
Reinforcing mesh is fixed to the secondary structure (purlins) which
sisilation/ sarking then sits on top of.
Suspended ceiling
• A suspended ceiling system may be used
for the office space, as it is capable of
spanning long distances
• Permits low building costs overall
• Lightweight, non-load bearing
• Panels are suspended from wires, and
have similar flexibility to plaster.
Envelope systems (office)
• Glass walling
• Many structural glass walling systems exist, and range in
complexity and structural makeup depending on what is
desired
• One of the systems available is pilkington planar
• Complete glass walling allows for plenty of natural light
• Expensive and not fire rated
• Although does look good & is best used in conjunction
with other systems
Envelope systems (office)
• Brick veneer
• Perfect for low-scale
office space
• Plenty of available skilled
labour & a wide range of
products in a competitive
market
• Reasonably cost
effective, although may
not be for larger scale
developments.
http://203.20.208.23/docs/project/bricksblocks/project_bricksblocks_1312200
2_092941.asp?site=Boral&AUD=buildingDesignProfessional&toggleItem=pro
jectgallery&menuItem=bricksblocks
Envelope systems (office)
• CSR fibre cement
• Easy to install on either steel or stud
frame
• Not fire rated by itself
• Allows for varied painted finishes
• Inexpensive; regarding both
materials, and labour costs- as
easily installation means skilled
trades are not required.
• Doesn’t look particularly good,
especially in consideration for the
image of a business or company
http://www.csrfibrecement.com.au/technical/techbull/fibrecem/B9C2DCD
EE4104A37B7B2E256E7F1B7C3/wFC126%20ExpressWall.pdf
Envelope systems (office)
• Composite panel systems; metal clad panels
• There are many manufacturers of metal clad panel
systems on the market
• Can be bare or color finished
• As these panels are clad in metal with various different
cores, they have high fire ratings
• Panel sizes are standardised, easing design & the
incorporation of windows and doors.
• Relatively high spanning capabilitie; requires less
structure
• Easy to install
• Give a clean and modern appearance to the building
Envelope systems (warehouse)
• Critical influences
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Cost
Appearance
End use of building- clients and worker demographics
Public exposure- image to be portrayed
Needs of occupants-light, insulation
Envelope systems (warehouse)
• There are two main envelope systems
widely used in the warehouse construction
industry;
• Concrete panels
• Steel sheet roofing
Concrete panels
• Concrete panels can either be can on-site,
called tilt-up concrete
• Or cast off site and ready delivered, called
pre-cast concrete
• In both cases reinforcement (trench mesh)
is spaced accordingly within the formwork,
with concrete then poured over top.
Concrete panels
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The benefits of using concrete panels either tilt-up or pre-cast:
Fire rating possible
Possibility of incorporating windows in the wall of the building
high quality finish
concrete not susceptible to damage from forklifts
System could be used for both warehouse and office
However is more expensive & its use is limited in very large warehouses.
Also is not a complete envelope system alone; metal roofing must also be
used.
Must have enough space on site for temporary formwork to be set up and
panels poured, or alternatively , the capacity for panels to be transported
and craned in.
Allows design freedom; the initial plasticity of concrete allows the casting of
complex shape, as well as the many available colors and textures (achieved
by incorporating aggregate in to concrete mix.)
Concrete construction
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Generally panels are fixed directly to steel supporting structures by clips
(cleats) or to concrete footings by grouted dowels in the cores.
Durability is a major advantage; long lasting and low maintenance
Once lifted in place by crane, temporary supports are put in place until
panels are secure
Also has good thermal properties
Difficult to add to or alter in any way.
High in compression, low in tension
Temporary connections must also be cast in the panels (for crane to attach
to for lifting in to position)
Overall this system can be erected fairly quickly
Cleats welded to primary steel structure and drilled in to concrete to prevent
movement
Concrete
• Load bearing:
• This system is relatively the same as non-load bearing
except for the concrete panels are designed to transfer
the load without the need for columns
• The positives of this system is that fast, cost effective
walls can be produced, which are ready for door and
window installation.
• Eliminates the need for perimeter columns
• Interior walls are easily lined or simply painted and
plates are cast in to take flooring beams, allowing quick
installation of levels.
Steel sheet
• Steel sheet is available in many different
profiles & alloys to suit different locations
and uses.
• Can be used for both roof and walls & is
very popular for this reason.
• Easy to incorporate in to a portal frame
structure
• Cost effective & relatively cheap to install
• Must be properly detailed to resist rust
Construction process
• Site visit: Leopold primary school, indoor neighbourhood centre. For
the housing of the basketball courts there was a requirement for a
column free space, this was achieved by use of the portal frame
system, utilised due to its great spanning capability. It has 39000mm
of clear span with 6800mm column spacing.
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Sequence of construction (from Chris Dywer, Lyons construction)
Sit cut
Services; plumbing, electrical
Foundations- cast in-situ bolts
Reinforced infill slab
Primary steel structure
Secondary steel structure
Sub roofing; mesh and sarking
Sheet metal; roofing & wall cladding
Internal fit out
Schematic design
Schematic design
Schematic design
Schematic design
Schematic design
Schematic design
Schematic design
references
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Blanc, Alan, Architecture and Construction in Steel, E & FN Spon, London, 1993
Brookes, Alan J., The building Envelope and Connections, Reed Educational, London, 1996
Brookes, Alan J, Cladding of Buildings, Longman Group Limited, U.S.A., 1983
BHP; Steel Profile, No. 77., Dec 2001
Ogg, Alan, Architecture in Steel, The Royal Australian Institute of Architects, Australia, 1987
http://oak.arch.utas.edu.au
www.bluescopesteel.com.au
www.lbconstruction.com
www.robertsonbuildings.com
www.tectonicsystems.com
www.steelwebinfo.com
www.onesteel.com.au
www.selector.com.au
www.cement.net.au
www.infolnk.com.au
www.bison.co.uk
www.ab.deakin.edu.au
www.strammit.com.au
Jeremy ham; lecture notes 2004