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Roofs: Tiles: terracotta, slate, shingles (timber), concrete tiles => lots of holes/ junctions Flat roofs-> you can walk on it o Not very waterproof Pitch of roof = degree Terracotta roofs-> 22° Ceramic and terracotta roofs -> impervious, waterproof substrate=> wet areas Zincalum coating: zinc + aluminium => lasts longer than zinc
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Critical vertical load equation =
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Effective length = kL Types:
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Overlapping to stop water
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Ascot Vale located 5km north-west of CBD
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Located in residential area Steep site which lead to some access issues Architect/designer: Kamara Design Builder: Burkhad Hansen
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Budget was reasonable Main areas of importance: perfect airtightness, seamless insulation, external solar heat gain control, fresh air supply o In the future it could be assumed that these will allow the house to be economically efficient for the residents as the cost of energy will be lower For the steel caissons 6m holes were drilled down with a radius of 0.3m Steel Caissons:
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Hole is deep and measured to fit steel casing Steel caissons are used as foundations which prevent soils beneath building from moving vertically They are deep foundations
The soil was moist and kept condensing Galvanised steel beams were used for wall posts as well as treated pine Double glazed and triple glazed windows were used
Brighton is 11km south-east of the CBD
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Budget was high Budget was much higher than Ascot Vale site Brighton -> relatively affluent suburb which could explain some of the inclusions in the house Project commencement: March 2 storeys with a basement Also includes: movie theatre, gym, wine cellar, indoor pool, private lift and carpark The lift was pre cast o Lifts are often precast and assembled on site, not very common to find in situ lifts o As the lifts were precast would have required cranes on site to assemble lift
Shotcrete pier soldier walls were also used Shotcrete is concrete that has been sprayed through a hose Can be either dry mix or wet mix Guided over structure (such as the pier soldiers) to form even layer
Shotcrete often used for swimming pools, retaining walls cellars, slope stabilisation, storm water retention works and basements
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Flat roofs: pitch= 1°-3° o Ponding tends to occur if concrete slab or roof decking absolutely flat o Increase weight, load on building => leakage o Very flat roofs -> waterproofing membranes required
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Pitched and sloping roofs: pitch= >3° o Timber or steel rafters o Beams & purlins o Trusses
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Decisions about roof slope influenced about roof lining material Tiles need to be greater slope than sheet metal roofing Tiles 15° or higher Concrete roofs o More expensive o Generally flat plates of reinforced concrete (or precast slabs) o Top surface sloped towards drainage points and entire roof surface finished with applied waterproofing membrane
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Structural Steel Framed Roofs o Flat: combination of primary and secondary roof beams for heavier finishes, or roof beams and purlins for lighter o Sloping: consist of roof beams and purlins and lighter sheet metal roofing o Portal frames: series of braced rigid frames (two columns and beams) with purlins for the roof and girts for the walls, walls and roof are usually finished with sheet metal Bending moments large -> material needs to be quite thick
o Trussed Roofs High strength to material ratio Series of open web type steel or timber elements Manufactured from timber or steel components, fixed together to form efficient elements able to span long distances Shape(slope) and material of the structural elements often determined by roofing material selected and functional requirements of roof
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Space Frames 3D plate type structures, long spanning in two directions Linear steel sections of various cross section types are wielded, bolted or threaded together to form matrix-like structures Useful for accommodating two way spans where large amount of glazing needed
Light Framed Roofs Gable roofs o Characterised by a vertical, triangular section of wall at one or both ends of roof o Consists of common rafters, ridge beams and ceiling joists o Where roof overhands the gable end wall outriggers are used o Materials: timber, cold-formed steel sections (& also sometimes heavier steel (UB or PFC) for major beams) o Use less commonly due to trusses
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Galvanic series, order of tendency to give up ions to other metals and corrode
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Ion transfer happens when metals are directly in contact with each other or they are in an environment (water/moisture) that facilitates transmission of ions (electrolysis) Reduce risk of corrosion-> metals separated by an insulator such as rubber gasket or kept away from sitting in moisture Galvanised steel -> coated by thin layer of zinc to protect steel from rusting Water related damage o Oxidation and corrosion o Metals can react with oxygen => oxide which sometimes protects but other instances can result in corrosion of metal o Aluminium oxides to form protective layer
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Hip roofs o Characterised by vertical, triangular section of wall at one or both ends of roof o Roof consists of common rafters, hip rafters, valley rafters, jack rafters, ridge beams and ceiling joists o Materials: timber, cold-formed steel sections
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Rust steel = undesirable corrosion
Aluminium: very light, non-magnetic and non-sparking, easily formed, machined and cast, alloy with other elements, expensive => extruded sections, cast door handles and catches for windows, rolled= cladding panels, heating and air-son systems
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Protect against water to reduce corrosion o avoid prolonged exposure to moisture (e.g. crevices and flat horizontal surfaces) o seal against moisture (e.g. enamel or paint metal surfaces) o chemical treatment (i.e. galvanised steel)
Iron: Very reactive chemically, good compressive strength • Wrought iron: iron heated and hammered • Cast Iron: iron melted and molten metal poured into moulds • Steel = alloy of iron and carbon • Properties: Strong and resistant to fracture,Transfers heat and electricity, Can be formed into many different shapes, Long lasting and resistant to wear ( if properly protected)
Structural Steel • Framing: columns, beams, purlins, stud frames • Hot rolled steel: while metal is hot, primary structural elements, often protected from rusting and corroding by coatings, joints welded or bolted • Cold formed steel: sheets that have been produced and cooled down, secondary structure, protected by hot dip processes, joins bolted or screwed • Reinforcing bars: due to good tensile resistance used w/ concrete = reinforced concrete, deformation on bars assist with bonding concrete
Other • Sheeting: cladding and roffing- must be protected from weather exposure • Stainless steel alloys: Chromium main alloying element (min. of 12%), used harsh environments or where specific inert finishes are required (e.g. kitchens, operating rooms etc.), Wall ties in cavity walls often made from stainless steel due to corrosion resistance, Very, very rarely used as primary structure due to cost (only in harsh environments)
Copper: turns green when exposed to weather forprolonged time (oxidisation), Very malleable and ductile, Good conductor of heat and electricity => roofing material, hot and cold domestic water and heating pipework, electrical cabling Zinc: Lustrous metal, Brittle at ambient temperatures but malleable at 100° to 150°, Reasonable conductor of electricity=> plplating thin layers onto iron or steel (galvanising), production of roofing material Lead: Used less commonly, Very soft, highly malleable, ductile, Relatively poor conductor of electricity, Very resistant to corrosion but tarnishes upon exposure to air=> was used for roofs, flashing strips => TOXIC Tin: Malleable, somewhat ductile, highly crystalline structure, Resists distilled, sea and soft tap water, Attacked by strong acids, alkalis and acid salts ,Oxygen in solution accelerates attack => rare (usually decorative) Titatinium: Excellent corrosive resistance (almost as resistant as platinum), High strength to weight ratio, Light, strong, easily fabricated metal with low density, very expensive=> stron light-weight alloys, attractive and durable cladding Bronze (copper + tin): corrosion resistant but much harder, an be used in engineering and marine applications => Bearings, clips, electrical connectors and springs
Brass (copper +zinc): malleable, low melting point, east to cast, not ferromagnetic => elements in where friction required (e.g. locks, gears, screws), also fittings
Purlin: One of several horizontal structural members that support roof loads and transfer them to roof beams. Alloy: A mixture of two or metals. Soffit: The underside of a part or member of a structure, such as a balcony, beam, stairway or arch.
Cantilever: Structural member supported at one end only.
Top Chord: The top member of a truss Portal frame: Rigid structural frame of two uprights and one cross beam at the top.
Rafter: One of a series of sloping parallel beams used to support a roof covering. Eave: The part of the roof that meets or overhands the walls of a building.
Advanced Precast. (2007). Centrelink national support. Retrieved from http://dev.majestic.com.au/ap01/index.php?option=com_content&view=article &id=128&Itemid=154Ching, F. D. K. (2008). Building Construction Illustrated. (4th ed.). Hoboken: Wiley. Australian Concrete Pumping Logistic. (2014).Shotcreting. Retrieved from http://www.acplwa.com/services/shotcreting-perth/ Crestwood Tubulars Inc. (2014). Caissons: Steel pipe for caisson use. Retrieved from http://www.crestwoodtubulars.com/caissons.html Dictionary of Construction. (2014). Definitions. Retrieved from http://www.dictionaryofconstruction.com/ Google. (2014). Google maps. Retrieved from https://maps.google.com.au/ The Free Dictionary. (2014). Roof purlin. Retrieved from http://encyclopedia2.thefreedictionary.com/roof purlin