LOGBOOK Week 1 In the first week, we built a building with the material ‘MDF’. It is medium density fibreboard. MDF is an engineering wood product, it is stronger and much denser. This is a very common material, we can find it everywhere.
In order to finish this building in one and a half hour, my team decided to use solid structural system to build up this model building so that our building will not collapse easily. Our design is based on the Roman amphitheatre. Therefore, the enclosure system and aesthetic qualities can be acceptable. The exterior walls interior spaces from noise and provide security and privacy. Here is the base of our building. The size of the building is actually big enough to maintain a person. The piece of MDF which
was put in the middle is a centre point so that we can make sure that the diameters all had the same length.
. We made a entry for the dinosaur to come in. Here is the door. The door provide physical access. My job is basically add up the material.
This is our enclosure system, the exterior walls proivdes security and privacy. After we finished this part, we found that we were running out of time and material. We spent too much time and half box of material on the base. However, our goal was to build as high as we can, so I brought up a point which is, in fact, our building are not stipulated to be even, therefore, eventually we decided to force on one side in order to reach the highest.
This was what we continuous to do afterwards. The building was gradually losing shape.
This building was untimately finished. While my team members were trying to reach as higher as possible, I added a window for our building. As an enclosure system, windows probide access to light, air, and views. However, for this particular building design, windows are actually not necessarily needed. Because our building had no roof. Finally we were not able to reach our goal because we were running out of materials. We wanted to use less material to make a great impact. So we turned the way to put our materials. Though the hight got higher, it became easier to collapse. Here is our building. The economic considerations are satisfied beause first of all, the material is not expensive. Secondly this building doesn’t need a lot of equipment/
Week 2 Last week, our team did another building which was built by sticks. This time, we choose to use trangle as base. Because trangle can maintain the shape quite well. And then add three sticks vertically. And then on the top of three sticks, we put a star opon it. It not only can prefectly maintain the shape but also can increase the Aesthetic Qualities. We just keep repeating the same work. As the same as last time, our goal is to reach the highest point.
Sticks and stars are dead load, they acted vertically doward on this structure. However, we ignored the dynamic load, it seem like the structure was shaking and varying. That why we added the extra stricks on three sides of the structure.
We were all trying to glue the stick. This is the view from the top of the structure.
Week 3
CLAY BRICKS – JOINTS Mortar joints are usually 10 mm (vertical joints are called perpends and horizontal joints are called bed joints). There are a range of joint finishing profiles which are selected depending on the type of brick, weather exposure and aesthetics.
PROPERTIES Hardness Fragility
BRICKS Medium-high. Can be scratched with a metallic object Medium- can be broken with trowel
Ductility
Very low ductility
Flexibility / plasticity
Very low flexibility and plasticity
Porosity / permeability
Conductivity
Medium-low. Becomes soaked only if placed in prolonged contact with water. Medium. Approximately 2-2.5 more dense than water. Poor conductors of heat and electricity
Durability / life span
Typically very durable
Reusability / recyclability
High. Can be re-used with no change or crushed to be used as recycled aggregate. Tends to be locally produced
Density
Sustainability & Carbon footprint Cost
Generally cost effective but required labour costs should also be considered
CONSIDERATIONS Bricks are permeable (non – waterproof) Advantages: -
They can be joined with water based mortar If adequately ventilated so that any wetness can escape, they will not deteriorate.
Disadvantages: -
They absorb moisture and expand overtime >>expansion joints required Salts and lime from the soil can be drawn up through the bricks when in contact with the ground. This may cause serious pathologies and / or aesthetic problems such as EFFLORESCENCE.
Concrete Blocks – Provenance Are manufactured from cement, sand, gravel and water. The manufacture process involves mixing, moulding and curing.
USES: Mainly used in the construction of walls both load bearing (structural) and non-load bearing (dividing and decorative walls)
To provide greater structural resistance to lateral loads, concrete masonry units are often strengthened with steel reinforcing bars and then filled with grout.
PROPERTIES HARDNESS Fragility
CONCRETE BLOCKS Medium-high. Can be scratched with a metallic object. Medium. Can be broken with trowel.
Ductility
Very low ductility.
Flexibility / Plasticity
Very low flexibility and plasticity
Porosity / permeability
Conductivity
Medium. Some Concrete blocks are sealed to reduce the opportunity for water absorption. Memedium. Approximately 2-2.5 more dense than water. Poor conductors of heat and electricity
Durability / life span
Typically very durable.
Reusability / Recyclability
Medium. Sometimes re-used with no change but more often crushed to be used as aggregate in other concrete products. Inclusion of recycled and waste products from other processes is allowing a positive reduction in carbon footprint and increase in sustainability for many concrete products. Generally cost effective but labour penalties are often applied as the large format units mean construction usually progresses at a faster rate.
Density
Sustainability & Carbon footprint
Cost
CLAY BRICKS VS CONCRETE BLOCKS: Concrete shrinks over time while clay bricks will expand. Concrete blocks shrink for several reasons. The cement paste reduces in volume as it hydrates and drying shrinkage occurs as water is lost to the atmosphere. Clay Bricks tend to absorb moisture from the atmosphere and gradually expand. Movement joints are required for each material.
Stone: PROPERTIES Hardness
STONE Large range generally igneous is hardest, then metamorphic and then sedimentary Largely geometry dependant (thickness to surface area ratio) Most stones have very low ductility
Fragility Ductility Flexibility / Plasticity
Most stones are rigid (very low flexibility and plasticity) Large range
Porosity / permeability Density
Largely depending on stone type, stones most often used in construction. Are 2 ½ to 3 times more dense than water Stones are generally poor conductors of heat and electricity Typically extremely durable
Conductivity Durability / Life span Reusability / recyclability
Very high. Can be re-used with no change or reworked into new shapes for new uses. Transport energy is the main factor. Stone sourcing has a high environmental cost. Largely dependant on Labor and scarcety.
Sustainability & carbon footprint Cost
Igneous
Type of stone
Sedimentary
Metamorphic
Week 4 1. 2. 3. 4. 5.
Spacing and Span Floor and framing systems Concrete In situ concrete Pre-cast concrete
SPAN AND SPACING Span is the distance measured between two structural supports. Span can be measured between vertical supports (for a horizontal member) or between horizontal supports (for a vertical member) Span is not necessarily the same as the length of a member.
SPAN AND SPACING Spacing of the supporting elements depends on the spanning capabilities of the supported elements
Concrete
FLOOR AND FRAMING SYSTEMS:
Steel
Timber
1. Concrete systems: SLABS of various types are used to span between structural supports. These can be one-way or two-way span.
2. STEEL SYSTEMS: Steel framing systems take various forms, with some utilising heavy gauge STRUCTURAL STEEL members and other using LIGHT GAUGE steel framing. In many instances a combination of member types and materials are combined (eg. Heavy and light members) depending on their structural function. Girders (main beams) and joists are shown below.
Steel framing systems sometimes combine with concrete slab systems to where the particular benefits of steel framing and shallow depth floor slab systems and desired. The spanning capabilities of the particular materials help to determine the spacing requirements of the supports.
Timber systems: Traditional TIMBER FLOOR FRAMING systems use a combination of BEARERS (primary beams) and JOISTS (secondary beams). The span of the bearers determines the spacing of the piers of stumps and the spacing of the bearers equals the span of the joists.
CONCRETE – PROVENANCE When the cement powder and water are mixed, a chemical reaction takes place and heat is released. This process is called hydration. During this process crystals are formed that interlock and bind the sand, crushed rock and cement/water paste together.
If too much water is add to the concrete mix, the final concrete will not be strong enough. (Weak) If too little water is added, the concrete mixture will be too stiff and it will be very difficult to work with (unworkable)
PROCESS: One of the great advantages of concrete is that it is fluid and shapeless before it hardens. It can be formed in to any shape we desire. FORMWORK is the term used for the temporary support or moulds used to hold the liquid concrete in place until it becomes hard. Formwork can be built at the building site –IN SITU- or in a factory –PRE CAST- out of a range a different materials – timber, metal, plastic, formply etc.
WALL FORMWORK: -
Spreaders – keep formwork apart Formwork ties Plywood sheathing Inner surface of panels leaves an impression on concrete Timber studs Horizontal walers reinforce the vertical members Sill plate Bracing
During the curing process the formwork needs to be supported as the weight of the wet concrete is very heavy. This is achieved by using props and bracings of various types.
Concrete generally reaches 75% of its compressive strength in approximately 7 days with testing for the required strength occurring at 28 days
Once the concrete is hardened and strong enough, the formwork is carefully removed. Formwork is often removed, stored and reused or it may stay in place forever (sacrificial formwork)
Sand-blasted Exposed aggregate
CONCRETE – FINISHES
Raked finish Bush hammered Board marked Board & Batten
Concrete – REINFORCEMENT Concrete is also known as ‘artificial stone’. The suggests that the properties of concrete and stone are similar. Concrete is very strong in compression but is weak in tension. To improve its structural performance, steel (very strong in tension) reinforcement in the form of MESH or BARS is added. The resulting material is what we know as REINFORCED CONCRETE.
Properties Hardness
Concrete High. Can be scratched with a metallic object
Fragility
Low. Can be chipped with a hammer
Ductility
Very low ductility
Porosity / permeability
Conductivity
Medium-low. Depending on proportions and components. Medium-high. Approximately 2.5 more dense than water Poor conductor of heat and electricity
Durability / life span
Typically very durable
Reusability / recyclability
Medium-low. Can be partially re-used when crushed to be used as aggregate for new concrete elements. High embodied energy. NON-RENEWABLE. Long lasting. Generally cost effective. Labor dependant for formwork & pouring.
Density
Sustainability & Carbon Footprint Cost
CONCRETE – CONSIDERATIONS Concrete is permeable (not completely waterproof). This is one of the main sources of problems in concrete. If the steel bars are too close to the surface they will not be protected from moisture and oxidation. This will cause both aesthetic and structural degradation of the concrete.
Another common cause of problems is poor vibration of the concrete during the pouring process. Concrete is vibrated to get rid of the air bubbles that get caught during the pouring process. These bubbles can compromise the structural performance of the element and, in a worst case scenario, result in the element failing.
In situ concrete: is any concrete element that has been poured into formwork and cured on the building site. This process includes the fabrication and assembly of the FORMWORK, placing any required REINFORCEMENT, the pouring, vibration and the curing of the concrete.
Uses: in a great many applications, it is generally used for structural purposes. (either self supporting or as primary structure) Widely used in footings, retaining walls ,and all bespoke (not standard) structural element.
Sometimes concrete is sprayed into place using a pressure hose (SHOTCRETE). This is useful for landscapes, swimming pools, basement walls between piers or overhead surfaces Construction joints
Joints
Control joints
divide the construction into small
proportional to the temperature differerntial, The material coefficient and the dimensions of the piece
Both
potential weak points
Pre-cast concrete- uses: Widely used in many different applications. It is often associated with the structure of a building, bridge or civil works, forming part of the primary structure or self-supporting panel type elements. Rarely used in footings, common in retaining walls, walls and columns.
Construction joints JOINTS Structural joints
Construction and structural joints will greatly depend on the desired aesthetic outcome.
CONSIDERATIONS: Pre-cast concrete elements can be limited in size due to transport. On site changes are very difficult to incorporate.
Week 5 1. Columns 2. Wall system 3. Timber
Columns:
Short columns: Columns are considered short if the ratio of effective column length to the smallest cross section dimension is less than 12:1
Short columns will be structurally adequate if the load applied to the column cross section does not exceed the compressive strength of the material. Compressive Strength (pa) = Load (N)/ area (mm2) Short columns become shorter when a compressive load is applied and then fail by crushing (shear) when the compressive strength is exceeded (either by applying too great a load or if the cross-section is too small).
Long columns: Columns are considered LONG if the ratio of effective column length to the smallest cross section dimension is greater than 12:1.
Long Columns become unstable and fail by buckling. The shape of column cross-section determines the direction of the buckling. The actual length of LONG COLUMNS and how they are fixed at the top and bottom of the columns determines how they will buckle and how much load the column can carry. The EFFECTIVE length of the column is changed because the different fixing methods. The effective length is measured between the points of CONTRALIEXURE.
Concrete frames Structural Frames
steel frames Timber Frames (post and beam)
Wall systems:
load bearing walls
Concrete Masonry
Stud walls
Light gauge steel framing Timber framing
Concrete Frames typically use a GRID of columns with concrete beams connecting the columns together. Steel Frames typically use a GRID of steel columns connected to steel girders and beams.
Timber Frame (POST AND BEAM) typically uses a grid of timber POSTS or POLES connected to timber beams. BRACING of members between bays or at the corners of post/beam junction is required to stabilise the structure.
Load bearing walls: CONCRETE load bearing walls can be achieved using either in situ or precast elements. The load bearing PANELS may also provide support for SPANDREL PANELS over and link into other structural elements. (Such as floor stabs, roof structure, etc)
Reinforced Masonry load bearing walls can be constructed from CORE FILLED hollow concrete blocks or GROUT FILLIED cavity masonry. BOND BEAMS over openings can be created using special concrete blocks which are filled with concrete to bond the individual units together. After the concrete has cured, the temporary propping can be removed, leaving only the appearance of the concrete block wall. Bond beams are used as an alternative to steel or concrete LINTELS.
Solid masonry load bearing walls can be created with single or multiple skins of concrete masonry units or clay bricks. The skins of masonry are joined together using a brick (with HEADER showing in face of wall) or with metal WALL TIES placed within the mortar bed.
Cavity Masonry walls are typically formed from two skins of masonry. Advantages of this construction solution include: Better thermal performance and opportunities for insulation within the cavity. Better waterproofing (ability to drain water from the cavity) and the opportunity to run services within the wall cavity The presence of a DAMP PROOF COURSE and WEEP HOLES in a wall are indicators that the wall is a cavity wall rather than a solid wall.
Stud framing: Metal and timber stud framed walls use smaller sections of FRAMING TIMBER or LIGHT GAUGE FRAMING STEEL to meet the structural demands of the construction.
This smaller sections mean that the structural members are repeated at smaller intervals and require restraining along their lengths with rows of NOGGINGS to prevent the long thin members from BUCKLING.
Stud framing generally consists of TOP PLATES, BOTTOM PLATES, VERTICAL STUDS, NOGGINGS, CROSS BRACING and PLYBRACING.
BRICK VENEER CONSTRUCTION: Combinations of 1 skin of non-structural masonry and 1 skin of structural frame wall are widely used in the construction industry.
Wood to Timber: Outer bark Inner bark Provenance:
Cambium cell layer Sapwood Heartwood
Early wood: Rapid growth at beginning of growing season. Thin, large cells-lighter colour
Late wood: Slow growth, often limited by lack of water. Thick small cells-darker colour Gives the growth ring
Growth: generally one ring per year/ some climates may have more than one growth season per year/ fires or disease may produce an extra ring.
Direction, strength and stiffness:
Grain direction: determine the structural performance of wood.
Strong parallel to grain & stiff parallel to grain
Weak perpendicular to grain:
Seasoning (Drying):
WHY is timber seasoned? -
To adjust the moisture content so the timber is appropriate for the intended use To provide increased dimensional stability
WHAT moisture is removed from the wood? -
Free moisture (voids in cells) Bound moisture (cell walls)
HOW is the moisture removed? Timber is generally seasoned in one of three ways: -
Air seasoning (drying) – Cheap but slow – 6 months to 2 years per 50 mm thickness Kiln seasoning (drying) – Typically 20-40 hours to dry to -12% Solar kiln seasoning (drying) – less expensive to run
Moisture in wood cells Fibre saturation
100%
Unseasoned timber
Partially 25% seasoned timber
Seasoned timber
15%
TYPES: Different woods have different properties. We group them based on their biological provenance (and not based on their strength or density)
Softwoods: In Australia common SOFTWOODS include all conifer species: -
Radiate pine Cypress pine Hoop pine Douglas fir
Hardwoods: Native Australian HARDWOODS include all eucalyptus species: -
Victorian ash Brown box Spotted gum Jarrah Tasmanian oak Balsa wood (not and eucalypt nor an Australian timber but, surprisingly, a hardwood)
Green sawing: Quarter sawn – Growth rings parallel to short edge.
Advantages: -
Best grain shows on face Good wearing surface for floors, furniture Radial face preferred for coatings Lower width shrinkage on drying Less cupping and warp than other cuts Can be successfully reconditioned
Disadvantages: -
Slower seasoning Nailing on face more prone to splitting
Back sawn – Rings parallel to long edge of piece
Advantages: Season more rapidly - Less prone to splitting when nailing - Wide sections possible - Few knots on edge -
Disadvantages: - Shrink more across width when drying - More likely to warp and cup - Collapsed timber more difficult to recondition
Radial sawn – Face is always a radial cut
Advantages: - Dimensional stability - Less prone to warping, cupping - Less wastage in milling
Disadvantages: - Wedge shaped cross section - More difficult to detail - More difficult to stack
Properties Hardness
Timber
Fragility
Medium-low. Geometry dependant, generally will not shatter or break.
Ductility
Low. Some timbers in their green state can be manipulated into a range of shapes.
Flexibility / plasticity
High flexibility and medium plasticity
Porosity / permeability
High. Varies depending on seasoning, finishing (protection) and fixing.
Density
Extremely varied depending on timber type.
Conductivity
Poor conductor of heat and electricity
Durability / life span
Can very durable, varies depending on type, seasoning, finishing (protection) and fixing.
Reusability / recyclability
Very high. SECOND HAND TIMBER is very desirable.
Sustainability & carbon footprint
Very low embodied energy. Fully renewable if correctly sourced.
Cost
Generally cost effective. Labour dependant for onsite work. But also suited to highly efficient factory based manufacturing processes.
Medium-low. Most timbers can be reasonably easily marked.
Specifying & Handling Design detailing can and should minimise exposure to hazards. Always specify timber for a particular use /scenario, CONSIDER:
Size – depth x breadth - Make sure size is available before specifying - Length (0.3 metre increments) common maximum 6.0m – longer lengths in limited sizes
Strength Grade F-grade & MGP gradings are commonly used to identify the strength of particular timber elements.
Moisture content Seasoned < 15% Any timber > 15% is sold as unseasoned
Species of wood – different timber types provide variations in performance and appearance
Treatment or insect repellent treatments will be required
Availability – not all timber types or sizes are available in all locations.
Considerations: Knots – Weak points // cause slope of grain
Arris Knot
Centre Knots
Edge knot
Slope of grain
Durability – Good practice Water related DAMAGE Fungal attack often occurs when moisture content of wood > 20% Swelling, shrinkage can cause cracks
PROTECTION against water AVOID exposure (when possible) SEAL against moisture movement – paint Particular care is needed with end grain – seat before assembly
Isolate timber from INSECT attack (termites and borer etc) Chemical barriers / physical barriers between ground and timber
Protect timber from sunlight and heat direct sunlight can cause excessive drying. Shrinkage direct sunlight breaks down wood / cellulose light colour paints are best.
Other Hazards -
Fire Chemical exposure
Engineered Timber – solid products
LVL – laminated veneer lumber Made from laminating thin sheets of timber, Most laminates with grain aligned to longitudinal direction, Very deep and long sections possible, High strength USE – Mainly Structural (beams, posts, portal frames)
GLULAM – GLUE LAMINATED TIMBER Made from gluing pieces of dressed sawn timber Together to form a deep member Most laminates with grain aligned to longitudinal direction, USE – Mainly structural (beams, posts, portal frames)
CLT – CROSS LAMINATED TIMBER
Made by gluing and pressing thin laminates together to form a sheet, Laminate grain laid in alternate directions (90 degrees) Provides strength in two directions USES – structural panels (horizontal and vertical) LOOKE AT: the forte building – Melbourne Docklands
Engineered Timber – sheet products
PLYWOOD – made by gluing and pressing thin Laminates together to form a sheet, Grain in laminates in alternate directions Strength in two directions, USE – Structural bracing / structural flooring / Formworks/ joinery/ marine/ applications
MDF – MEDIUM DENSITY FIBERBOARD Made by breaking down hardwood or softwood waste into wood fibres. Combining it with wax and a resin binder by applying high temperature and pressure. MDF is generally more dense than plywood. USES – Non-structural applications (joinery)
CHIPBOARD & SRANDBOARD
Made by layering hardwood or softwood residuals (chips, strands) in specific orientations with wax and a resin binder by applying high temperature and pressure. USES – As part of structural systems (e.g. flooring) / cladding finish
ENGINEERED TIMBER – OTHER MANUFACTURED PRODUCTS The rationale to the following set of products lies in their ability to use materials very efficiently and their ability to accommodate services within their depth.
I BEAMS – Timber / LVL flanges, plywood / OSB webs lightweight, suitable for medium spans USES – floor joists / rafters
BOX BEAMS – timber / LVL flanges, two plywood / OSB webs suitable for larger spans, torsionally stiff, can use decorative plywood USES – floor joists / rafters/
TIMBER FLANGED STEEL WEB JOISTS – lightweight, open webs give access for service webs by light tubes, solid rounds, corrugated sheets USES – floor joists / rafters/
I BEAMS
TIMBER FLANGED STEEL WEB JOISTS
BOX BEAMS
This week, we did an activity which is called ‘modelling case study structural details’ during the tutorial. Here is our class’s structural detail. It is a STEEL FRAMING ISOMETRIC. We are separated by small groups and required to build a part of this structure.
Here is the part which our group did. This structure is called ‘CANOPY STRUCTURE’.
Initially, we drew an amplifying structure. The ratio is 1:5. Then we sticked the timber stick upon the line which we just drew by super glue.
Here is the finished one of the initial part.
Then we used a blade to get the whole part into separate parts.
Then we carefully used the blade to hollow out the white part so that the shape can be more obvious.
Then we sticked the separate parts into a big structure.
Eventually, our part of the big structure is done.
Week 6 1. 2. 3. 4. 5.
Steel trusses Roof system Metal Ferrous Metals and alloys (containing iron) Aluminium, zinc, copper, lead, tin, titanium, Bronze, Brass
Uses: Extruded sections are common for window frames and other glazed structures such as balustrades/handrails. Cast door handles and catches for windows Rolled aluminium is used for cladding panels, heating and air-conditioning systems. Aluminium reacts with air creating a very fine layer of oxide that keeps it from further oxidation giving it that matter natural finish Other finish treatments can also be applied. The most common treatments are power coating and anodisation.
Copper: distinctive properties: The first metal used by humans in around 7000BC. Can be found as pure deposits in nature. Copper is reddish with a bright metallic lustre when polished and turns green when exposed to the weather for a prolonged time. (Oxidisation) Very malleable and ductile. Good conductor of heat and electricity (second only to silver in electrical conductivity but is less expensive)
Copper â&#x20AC;&#x201C; uses: Traditionally used as ROOFING MATERAL, natural weathering causes copper to develop a green coloured patina over time. It is also widely used for hot and cold domestic water and heating PIPEWORK. And electrical cabling.
Zinc: Present use in construction: Plating thin layers of zinc on to iron or steel is known as galvanising and helps to protect the iron from corrosion. This is particularly useful in the production of roofing material.
Zinc is also used on its own as a CLADDING material for both roofs and walls.
Distinctive properties: Zinc is a bluish-white. Lustrous metal. It is brittle at ambient temperatures but is malleable at 100 to 150°. It is a reasonable conductor of electricity.
LEAD: History: lead pipes bearing the insignia of Roman emperors, used as drains from the baths, are still in service today.
Present use in construction: lead was used frequently for roofs, cornices, tank linings and flashing strips for waterproofing. It is less commonly used to day because it is now known to be toxic to humans. When absorbed into the body in high enough doses, lead
can be toxic.
Distinctive properties: Lead is a bluish-white lustrous metal. It is very soft, highly malleable, ductile, and a relatively poor conductor of electricity. It is very resistant to corrosion but tarnishes upon exposure to air.
TIN: History: Tine extraction and use can be date to the beginnings of the BRONZE AGE around 3000BC, where it added to copper to make Bronze.
Present use in construction: Very rare today (generally only decorative). Tine was used in building for lining lead pipes (TOXIC), and occasionally as a protective covering for iron plates and for small gas pipes/tubing.
Distinctive properties: Ordinary tin is a silvery-white metal, is malleable, somewhat ductile, and has a highly crystalline structure. Tin resists distilled, sea, and soft tap water, but is attacked by strong acids, alkalis, and acid salts. Oxygen in solution accelerates the attack.
Titanium: Present use in construction: Titanium is used in strong light-weight alloys, making an attractive and durable cladding material, though it is often prohibitively expensive. Distinctive properties: Titanium is well known for its excellent corrosion resistance (almost resistant as platinum) and for its high strength-to-weight ratio. It is light, strong, easily fabricated metal with low density. In thin sheets, it is not very stiff and appears as â&#x20AC;&#x2DC;pillowyâ&#x20AC;&#x2122; rather than flat.
Bronze (copper + tin) History: A small amount of tin added to copper made a new, harder metal called bronze. This was the first copper alloy. (Circa, 2000BC)
Present use in construction: Bronze parts are tough and typically used for bearings, clops, electrical connectors and springs. Bronze was often used for external application, prior to the discovery of aluminium, due to its toughness and resistance to corrosion.
Distinctive properties: Bronze is a particularly important alloy of copper and tin. Like copper it is corrosion resistant but it is much harder and can be used in engineering and marine applications.
Brass (copper + zinc) History: Although alloys of copper and zinc have been in use for over 2000 years, direct brass alloying was only introduced around the 16th century.
Present use in construction: Brass parts are tough and typically used in elements where friction is required such as locks, gears, screws, valves. It is also commonly found in fittings. (Knobs, lamps, taps, etc)
Distinctive properties: Brass is malleable and has a relatively low melting point and is easy to cast. It is not ferromagnetic.
Week 7 1. 2. 3. 4. 5.
Detailing for moisture Detailing for heat Paints Rubber Plastics
-
Upturned edges and sloping surfaces use gravity to lead water to the outside
-
Drips and cavities form capillary breaks between two surfaces wide enough to prevent the capillary action of moisture through the space.
-
Interlocking seams form a labyrinth that inhabits the passage of water.
-
Water can penetrate a joint through surface tension and capillary action
-
Capillary action is a manifestation of surface tension by which the greater adhesion of a liquid to a solid surface than internal cohesion of the liquid itself causes the liquid to be elevated against a vertical surface.
Turn up 2â&#x20AC;&#x2122; (51)
Head flashing
Sill Flashing
-
Threshold
Slope paving 1%
Base course flashing
Detailing for moisture: Neutralising the forces:
Gravity strategies Air pressure differential strategies Surface tension and capillary action strategies
1. Gravity strategies: -
Typically use SLOPES and OVERLAPS to carry water away from the building using the force of gravity.
2. Air pressure differential strategies: With gusts of wind, water can still be moved through a complex labyrinth if there is a difference in the air pressure between the outside and inside. The water is ‘pumped’ from the HIGH pressure to the LOW pressure.
Rain screen assemblies: If an AIR BARRIER is introduced on the internal side of the labyrinth, a ventilated and drained PRESSURE EUQALISATION CHAMBER (PEC) is created and the water is no longer ‘pumped’ to the inside of the assembly.
3. Surface tension and capillary action strategies: Typically use a DRIP or a BREAK between surfaces to prevent water clinging to the underside of surfaces (such as a WINDOW SILL or PARAPET CAPPING)
These gaps and breaks prevent water reaching and entering openings because the surface tension of the water is broken at the drip/gap location. Instead, the capillary action movement of the water stops and the water is released in drop form.
Drips and cavities form capillary breaks between two surfaces wide enough to prevent the capillary action of moisture through the space.
Detail for Heat:
Radiation Conduction
Controlling Heat: Thermal Mass Controlling air leakage
1. Controlling Heat â&#x20AC;&#x201C; Radiation Radiation can be controlled by using:
-
Reflective surfaces such as low-e glass, reflective materials to reduce building elements from becoming warm/hot.
-
Shading systems like verandahs, eaves, solar shelves, blinds, screens and vegetation to prevent radiation striking the building envelop.
2. Controlling Heat â&#x20AC;&#x201C; Conduction: -
Thermal insulation to reduce heat conduction.
-
Thermal Breaks made from low conductive materials like rubbers and plastics to reduce the heat transfer from outside to inside (and also inside to outside) when using highly conductive materials like metals.
-
Double Glazing or triple glazing so that the air spaces between glass panes reduces the flow of heat through the glazed elements.
3. Controlling Heat â&#x20AC;&#x201C; Thermal Mass: Large areas of exposed thermal mass can be used to absorb and store heat over a period of time. When temperature drop, the stored heat is released. This system works well when there are large differences in temperatures between day and night. Materials traditionally used for thermal mass include: - Masonry
-
Concrete
-
Water bodies
4. Controlling Air Leakage: The principle of airtight detailing is similar to watertight detailing. If a building has:
-
An opening Air present at the opening A force to move air through the opening
Air will move through the building and the spaces will become drafty in cold weather, uncomfortable and it will be difficult to maintain adequate levels of heating because air is leaking out of the building envelope.
Strategies to stop air leakage include:
-
Eliminating any one of the causes (above). Wrapping the building in polyethylene or reflective foil SARKING to provide an AIR BARRIER. WEATHER STRIPPING around doors and windows and other openings.
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The use of a vapour retarder is generally recommended to protect the insulation layer of flat roof assemblies in geographic locations where the average outdoor temperature in January is below 40째 F (4째c) and the interior relative humidity in winter is 45% or greater at 68째F (20째C).
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When a vapour retarder is present, topside vents may be required to allow any trapped moisture to escape from between the vapour retarder and the roofing membrane. Consult roofing manufacturer for recommendations.
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Vapor retarders should have a flow rating of one perm or less and be installed with all seams at joints and openings lapped and sealed. In this case, a vapor retarder is sometimes referred to as an air barrier.
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Exterior sheathing, building paper, and siding should be permeable to allow any vapor in the wall construction to escape to the outside.
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Over unheated spaces, the vapor retarder is placed on the warm side of the insulated floor. The vapor retarder may be laid on top of the subfloor or be integral with the insulation.
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A moisture barrier, such as polyethylene film, is usually required to retard the migration of ground moisture into a crawl space.
Paints: 1. PROVENANCE & COMPOSITION 2. TYPES & USES 3. PROPERTIES – wide range depending on type. Provenance & Composition: Paints are liquid until they are applied on a surface forming a film that becomes solid when in contact with the air. Their main purpose is to protect (and colour) a particular element. Clear paints are called lacquers or varnishes.
Components: Binder – the film-forming component of the paint (polyurethanes, polyesters, resins, epoxy, oils) Diluent – dissolves the paint and adjusts its viscosity (alcohol, ketones, petroleum, distillate, esters) Pigment – gives the paint its colour and opacity. Can be natural. (Clays, talcs, calcium carbonate, silicas) or synthetic
2. Types & uses: 1.
Oil Based Used prior to PLASTIC PAINTS (water based) Very good High Class finishes can be achieved Not water soluble (brushes to be cleaned with TURPENTINE)
2.
Water based Most common today (except where particular finishes are desired) Durable and Flexible Tools and brushes can be cleaned with water.
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Properties – wide range depending on type. Generally: Colour consistency – The colour of the paint should resist fading, especially when outside in ultra-violet light (sunlight). Red dyes tend to be less stable in sunlight.
Durability – paints need to resist chipping. Cracking and peeling. Exterior painted surfaces have to resist the effect of rain, air pollution and the ultra-violet light in sunlight. Newer paint technologies such as power coating and PVF2 are harder and more durable.
Gloss – surface finishes can range from matt through to gloss.
Flexibility/plasticity – water based latex paint is more flexible than oil based paint. Gloss – surface finishes can range from matt through to gloss.
Rubber 1. 2. 3. 4.
Provenance Properties Types & uses Considerations
1. Provenance: Nature Rubber was first used by the Mayas and Aztecs in South America (13th century)
Synthetic Rubber was first made in the beginning of the 20th century. (Has a PETROCHEMICAL origin)
Source: It can be naturally sourced from the Rubber Tree (it is the treeâ&#x20AC;&#x2122;s sap) or It can be synthesised in a laboratory generating a range of variations (technically a PLASTIC)
Hardness – Harder rubbers resist abraision. Softer rubbers provide better seals. Fragility – low. Generally will not shatter or break. Rubber:
Ductility – High (when in heated state). Varied (in cold state).
Flexibility/plasticity – High flexibility, plasticity and elasticity
2. Properties:
Properties:
Rubber
Porosity/permeability
All rubbers are considered waterproof
Density
Approx 1.5x density of water
Conductivity
Very poor conductors of heat and electricity (ie useful insulators)
Durability/life span
Can very durable
Reusability/recyclability
High
Sustainability & Carbon Footprint
Embodied energy varies greatly between natural rubber (very low) and synthetic rubbers (medium). Renewable if correctly managed.
Cost
Generally cost effective.
3. Types & uses
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Natural rubber â&#x20AC;&#x201C; some of most common uses are: Seals Gaskets & control joints Flooring (for use in adverse conditions such as laboratories) Insulation (eg. Around electrical wiring) Hosing & piping
Synthetic – MAIN TYPES:
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EPDM – mainly used in GASKETS and CONTROL JOINTS NEOPRENE – mainly used in CONTROL JOINTS SILICONE – seals
Considerations: Weather related damage: Rubbers can lose their properties when exposed to weather (especially sunlight)
Protection: avoid or minimise sun exposure (when possible)
Plastics: 1. 2. 3. 4.
Provenance Properties Types & uses Considerations
1.
Provenance Sourcing- the plastics we use today are made from elements such as: carbon, silicon, hydrogen, nitrogen, oxygen and chloride combined by chemical reactions into monomers. The monomers combine with each other to form polymers. Polymers are long chains of monomers (molecules) that make the substances we call PLASTICS.
2. Properties: - wide range depending on type. Generally:
Properties
Plastics
Hardness
Medium low. Depending on TYPE.
Fragility Ductility
Low medium. Generally will not shatter or break. Sunlight and high temperatures can degradate some plastic quite quickly. Can be fragile in degraded state. High (when in heated state). Varied (in cold state)
Flexibility/plasticity
High Flexibility and plasticity
Porosity/permeability
Many plastic are waterproof
Density
low (0.65x Density of water for polypropylene to 1.5x for PVC) Very poor conductors of Heat and electricity
Conductivity Durability/life span
Can very durable, varies depending on type, finishing (protection) and fixing
Reusability/recyclability
High for thermoplastics and elastomers/very limited for thermosetting plastics
Sustainability & Carbon Footprint Cost
Embodied energy varies greatly between (recycled/not recycled). Plastic are petrochemical derives so not a renewable resource. Generally cost effective.
Considerations: Weather related damage: Plastic properties DEGRADE when exposed to weather (especially sunlight) and need to be checked and maintained.
Protection & Management: Avoid or minimise sun exposure. (When possible) Some plastics have very high expansion/contraction coefficients.
3. Types & uses: 1.
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Thermoplastics – mouldable when heated and become solid again when cooled. Can be RECYCLED.
Polyethelyne (polythene) Polymethyl methacrylate (Perspex, acrylic) Polyvinyl Chloride (PVC, vinyl) Polycarbonate
2. Thermosetting plastics – can only be shaped (moulded) once: -
Melamide Formaldehyde (laminex) – widely used for finishing surfaces.
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Polystyrene (styrene) – mostly used in insulation panels.
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3. Elastomers (synthetic rubbers) – refer to separate e-MODULE EPDM Neoprene Silicone
Week 8 1. Door & Door Frame Terminology 2. Window operation 3. Materials: glass
Door & Door Frame Terminology
Wood rail-and-stile doors consist of a framework of vertical stiles and horizontal rails that hold solid wood or plywood panels, glass lights, or louvers in place. The stiles and rails may be solid softwood or veneered hardwood.
Batten doors consist of vertical board sheathing nailed at right angles to cross strips or ledgers. Diagonal bracing is nailed between and notched into the ledgers. -
Used primarily for economy in rough construction Usually site-fabricated Tongue-and-groove sheathing is recommended for weathertightness. Subject to expansion and contraction with changes in moisture content.
Hollow Core Doors: Hollow core doors have a framework of stiles and rails encasing an expanded honeycomb core of corrugated fibreboard grid of interlocking horizontal and vertical wood strips. They are lightweight but have little inherent thermal or acoustic insulation value. While intended primarily for interior use, they may be used for exterior doors if bonded with waterproof adhesives.
Solid Core Doors: Solid core doors have a core of bonded lumber blocks, particleboard, or a mineral composition. Of these, the bonded lumber core is the most economical and widely used. The mineral composition core is lightest but has low screw-holding strength and cutouts are difficult. Solid core doors are used primarily as exterior doors, but they may also be used wherever increased fire resistance, sound insulation, or dimensional stability is desired.
Special Doors: -
Fire-rated doors have mineral composition cores. B-label doors have a 1 hour or 1-1/2 hour UL-approved rating. C-label doors have a 他 hour UL-approved rating. Sound-insulating doors have faces separated by a void or damping compound. Special stops, gaskets, and thresholds are also required.
Grades and Finishes -
There are three hardwood veneer grades: premium, good, and sound. Premium grade veneers are suitable for natural, transparent finishes. Good grade veneers are for transparent or paint finishes. Sound grade veneers are for paint finishes only; they require two coats to cover surface defects. Hardboard face panels are suitable for paint finishes. High-pressure plastic laminates may be bonded to the face panels. Flush doors may also be factory-finished partially with a seal coat or completely including prefitting and premachining for hinges and locksets.
Aluminium Windows Aluminium window frames are relatively low in cost, lightweight, and corrosion resistant, but because they are such efficient conductors of heat, synthetic rubber or plastic thermal breaks are required to interrupt the flow of heat from the warm to the cool side of the frame. Aluminium frames may have anodized, baked enamel, or fluoropolymer resin finishes.
Steel windows Steel window frame and sash sections are manufactured from hot-rolled or cold-rolled steel. Because steel is stronger than aluminium, these sections are more rigid and thinner in profile than aluminium sections, offer narrower sightlines, and allow larger lights to be installed in a given rough or masonry opening. Steel also has a lower coefficient of heat transfer than aluminium and therefore steel window frames do not normally require thermal breaks.
Wood windows Wood frames are thicker than aluminium or steel frames, but they are also more effective as thermal insulators. The frames are usually of kiln-dried, clear, straight-grain wood, factory-treated with a water-repellant preservative. The wood may be stained, painted, or primed for painting on site. To minimize the need for maintenance, the majority of wood frames are now clad with vinyl or bonded to acrylic-coated aluminium sections that require no painting.
Week 9 1. 2. 3. 4. 5.
Construction detailing: Movement joints Repairable surfaces & resistance to damage Cleanable surfaces Maintenance access Materials: Monolithic or composite?
Compressed
Construction detailing: Movement joints
As installed
Elongated
To provide an effective seal against the passenger of water and air, a joint sealant must be durable, resilient, and have both cohesive and adhesive strength. Sealants can be classified according to the amount of extension and compression they can withstand before failure.
Cleanable surfaces: Butt cove for resilient flooring Cleanable surfaces
Straight base for carpeted floors Top set cove for any flooring type Cove and cap strips
Maintenance access: Integrated ceiling systems incorporate acoustical, lighting, and air-handling components into a unified whole. The suspension systems, which typically form a 60’’x60’’ (1525x1525) grid, may support rather flat or coffered acoustical panels. Air-handing components may be integral parts of modular luminaires and disperse conditioned air along the edges of the fixtures, or be integrated into the suspension system and diffuse conditioned air through long, narrow slots between the ceiling panels.
MAIN RUNNERS are the principal supporting member of a suspended ceiling system, usually consisting of sheet-metal tees or channels suspended by hanger wires from the overhead structure.
CROSS TEES are the secondary supporting members, usually consisting of sheet-metal tees carried by the main runners.
EXPOSED GRID SUSPENSION SYSTEMS support the acoustical titles with inverted tees.
RECESSED GRID SUSPENSION SYSTEMS support acoustical tiles within rabbeted joints.
CONCEALED GRID SUSPENSION SYSTEMS are hidden within kerfs cut into the edges of the acoustical titles.
LINEAR METAL CEILINGS consist of narrow anodized aluminium painted steel or stainless steel strips. The slots between the spaced strips may be open or closed. Open slots permit sound to be absorbed by a backing of batt insulation in the ceiling space. Linear metal ceiling systems usually incorporate modular lighting and air-handling components.
Materials: Monolithic or composite? Monolithic materials are: -
A single material or Materials combined so that component are indistinguishable. (eg. Metal alloys)
Composite materials are created when: -
Two or more materials are combined in such a way that the individual materials remain easily distinguishable.
What are composite materials? -
Combination of materials which differ in composition or form Remain bonded together Retain their identities and properties Act together to provide improved specific or synergistic characteristics not obtainable by any of the original components acting alone
TYPES Composite materials come in many forms, but they can be grouped in to four main types: -
Fibrous Laminar Particulate Hybrid
eg. Products containing discontinuous or continuous fibres eg. Sandwich panels eg. Gravel and resins eg. Combinations of two or more composite types.
Fibre reinforced cement Fibreglass Composite materials
Aluminium sheet composites Timber composites Fibre reinforced polymers
Composite materials Fibre reinforced cement
Made From Cellulose (or glass) fibres, Portland cement, sand & water)
Common forms Sheet & board products (commonly called FC sheet) and shaped products such as pipes, roof titles etc
Common uses Cladding for exterior or interior (wet area) walls, floor panels. (under tiles)
Fibreglass
A mixture of glass fibres and epoxy resins. (glass fibres often used in a fabric or tape form)
Flat and profiled sheet products and formed/shaped products
Aluminium sheet composites
Aluminium and plastic
Plastic core of phenolic resin (or a honeycomb sheet) lined with two external skins of thins aluminium sheet.
Transparent or translucent rood/ wall cladding and for preformed shaped products such as water tanks, baths, swimming pools etc As a feature cladding material in interior and exterior applications
Timber composites
Combinations of solid timber, engineered timber (solid and sheet), galvanised pressed steel
Timber top on bottom chards with gal, steel or engineered board/ plywood webs
Beams (floor joists and roof rafters) and trusses.
Fibre reinforced polymers
Polymer (plastics) with timber, glass or carbon fibres.
Often associated with moulded or pultrusion processed products.
Decking (& external cladding), structural elements such as beams and columns for public pedestrian bridges using glass or carbon fibres, carbon fibre, reinforced polymer rebar.
Benefits Fibre cement building materials will not burn, are resistant to permanent water and termit damage, and resistant to rotting and warping. It is a reasonably inexpensive material. Fibreglass materials are fire resistant, weatherproof, relatively light weight and strong.
Reduced amounts of aluminium are required and lighter weight, less expensive sheet can be produced which are weather resistant, unbreakable and shock resistant. A variety of finishes can be specified and â&#x20AC;&#x2DC;seamlessâ&#x20AC;&#x2122; details can be achieved with careful cutting, folding, bending and fixing. Minimum amount of material is used for maximum efficiency. Cost effective easy to install, easy to accommodate services. High-strength FRP materials with glass or carbon fibre reinforcements provide a strengthto-weight ratio greater than steel. FRP composite materials are corrosion-resistant.
Week 10
Statue of liberty: Galvanic corrosion History: The stature of Liberty was designed by Auguste Bartholdi. The copper skin is supported on an iron skeleton designed by Gustave Eiffel.
Copper oxidisation: When copper is exposed to the atmosphere. It reacts with oxygen. The copper starts to dull, first becoming a darker brown colour and then forming a green copper oxide patina.
Initial connection detail consideration: Galvanic corrosion between the copper skin and iron frame (DISSIMILAR METALS) was considered at the same of construction and a solution that allowed for the separation of the two metals was devised.
The first solution The two materials were separated at their junctions by a layer of shellac-impregnated cloth.
ANODIC END
Magnesium Zinc Aluminium Structural steels Iron Tin Copper, Brass, Bronze Nickel (passive) Titanium Stainless steels
CATHODIC END
The problem: Over time, the shellac-impregnated cloth became porous and actually held moisture at the joint between the two different metals. This provided good conditions for galvanic corrosion and the iron began to corrode.
What happened? The connection system started to fail as the build up of corrosion products expanded and pulled the rivets away from the copper skin.
The second solution: To overcome this problem, the original iron armature frame was replaced with a Teflon-coated stainless steel structure. The selection of stainless steel was made after extensive corrosion resistance testing and consideration of the physical properties of the stainless steel and how well it would work with the existing copper skin.
The future: The new system still includes two different metals and so will require ongoing inspections and maintenance.