2014-Constructing Environments Log Book - Rebecah Wiesner

WEEK 1 Introduction to Materials:

Strength – Is it strong or week?

Some materials are strong in both Compression and Tension.

Stiffness – Stiff, Flexible, Stretchy or Floppy. Nylon ropes are strong, but not stiff.

Shape – Linear, Planar, Volumetric.

Material Behaviours – Isotropic or Anisotropic?

Economy and Sustainability – Cost, Impact on the environment, etc.

Bricks – Strong especially in compression and very stiff

Nylon Rope – Strong in tension, but not stiff

Basic Structural Forces: •

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A force is any influence that produces a change in the shape or movement of a body Forces are considered as vector quantities with both magnitude and direction They are represented as arrows with the length of the arrow proportional to its magnitude.

Tension: Tension is when and external load pulls on a structure causing the particles within the structure to move apart and hence stretch the material.

Compression: Compression is the opposite of tension. It occurs when a force pushes on an object or structure causing the particles within it to compact together resulting in a shortening of the material.

Static Loads: Static loads are loads that are applied slowly. They can be either live or dead loads.

These include people, furniture, rain, building elements and the weight of the structure itself.

Dynamic Loads:

Dynamic Loads are applied suddenly with rapid changes in magnitude and point of application. Examples of dynamic loads are wind and earthquake forces and precautionary measures need to be taken into account when building structures to minimize the effect of these forces.

Ground Pressure:

Ground Pressure is a horizontal force a mass of soil exerts on a vertical retaining structure.

WEEK 2

Frame Structure.

Structural Systems:

Solid Structures – Stone and brick,

strong in compression. Eg, Arches

Surface (Shell) Structures – Planar.

Eg, Sydney Opera House

Skeletal (Frame) Structures – Very efficient for transferring loads

Membrane Structures – Not very common in the built environment, but often used in sports stadiums.

Very efficient in tension

Hybrid – Air is an integral part of the structure

Frame Structure

Solid Structure

Construction Systems: Service Systems – Provide essential services to the building.

Eg, water, electricity, heating.

Structural Systems – To support and transmit loads safely to the ground.

Enclosure Systems – The roof, exterior walls, windows and doors.

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SOLAR PANELS

ESD and Selecting Materials:

Environmentally Sustainable Design features include insulation, solar and wind energy and using local materials as well as shelters for protection from the sun, windows for light, water harvesting and ventilation to moderate temperatures.

Embodied Energy:

Embodied energy is the energy involved in making and transporting products and materials as well as the construction of a building.

Embodied energy and Carbon Emissions can be reduced by using recyclable materials and materials that involve little transportation.

Structural Joints:

Fixed Joint

Roller Joints – Loads transferred in one direction, in other directions the roller will move.

Pin Joints – Allow rotation but no up/down or left/right movement.

Fixed Joints – Allow no movement, which can cause elements to bend easily.

WEEK 3

Structural Elements:

The design of a structural element is based on the loads to be carried, the material used, and the form and shape chosen for the element.

Modular: -­‐ Brick -­‐ Ashlar Stone

Mass Construction Materials

Generally strong in compression, but not in tension, they insulate well and are quite durable.

-­‐ Stone -­‐ Earth -­‐ Clay (Bricks) -­‐ Concrete

Mortar

Masonry Definitions Masonry refers to a building with units of various natural or manufactured products, usually with the use of mortar as a bonding agent.

Bond: The pattern or arrangement of the units Course: A horizontal row of units Joint: The way units are connected

Mortar: A mixture of cement or lime, sand and water used as a bonding agent

Masonry Material -­‐ Stone (slabs, ashlar blocks, rubble) -­‐ Clay (bricks, blocks) -­‐ Concrete (blocks, commons)

Masonry Construction

Vertical Elements: Walls and Columns

Horizontal and Curved Elements: Beams/Lintels and Arches

Bricks

Bricks are made from clay and are a standard size masonry unit. They are made by shaping clay and water and fired in a kiln. They expand over time.

Properties Hard, low ductility, low flexibility, medium fragility, medium density, very durable, high reusability.

Concrete Blocks A standard size masonry unit that shrinks over time; made by mixing, molding and curing concrete, sand, water and gravel. They can be hollow or solid and the holes allow for reinforcement. They can be structural or decorative elements and have similar properties to bricks.

Stone

Igneous stone is formed when molten rock (lava) cools. Eg. Granite, basalt, and bluestone

Sedimentary stone is softer and is formed when accumulated particles are subjected to moderate pressure.

Eg. Sandstone and limestone

Metamorphic stone like marble and slate is formed when the structure of igneous or sedimentary stone changes when subjected to pressure, high temperatures, or chemical processes.

Stone is generally hard, has low ductility and flexibility and is not fragile in thick blocks/slabs.

SANDSTONE

Geometry and Equilibrium

The centre of mass (centre of gravity) is the point about which an object is balanced. The location of the center of mass depends on the objects geometry.

Equilibrium is a state of balance or rest resulting from the equal action of opposing forces.

For equilibrium to exist the sum of the applied and reaction forces must equal zero.

Moment of Forces The moment of a force is the tendency to make an object or point rotate. Moment forces have a magnitude and a sense.

Mo = F x d (force x distance)

Foundations

The foundation is the lowest division of a building – its substructure – constructed partly or wholly below the surface of the ground. Its function is to support and anchor the substructure above and transmit its loads safely to the earth. In Australia the footings are the structure and the foundation is the ground.

Shallow Foundations

Shallow or spread foundations are used when the soil close to the surface has adequate bearing capacity. They are placed directly below the lowest part of the substructure and transfer vertical loads directly to the supporting soil.

Deep Foundations

Deep foundations are used when the soil under a structure is unstable or has inadequate bearing capacity.

They extend down through the soil and transfer the loads to sand, gravel or a more appropriate bearing stratum well below the surface.

WEEK 4

Span – The distance between two

structural supports

Spacing – The repeating distance between a series of similar elements

Spacing of the supporting elements depends on the spanning capabilities of the supported elements.

ROOF BEAMS

Beams

Beams are usually a horizontal structural element. The function of a beam is to carry loads along the length of the beam and transfer them to vertical supports.

Floor and Framing Systems Slabs – Slabs can span one or two ways. The thickness of the slab is usually the span divided by 30.

Steel Framing – It can take various

Timber Systems

Timber flooring/framing systems are very traditional. They use a combination of bearers (primary beams) and joists (secondary beams). The joists are usually the beams closest to the surface (top) of the floor.

forms and can sometimes be combined with concrete slabs. It can be heavy structural steel or light gauge framing.

FLOOR FRAMING

FLOOR FRAMING FOR DECKING

Concrete

Concrete is a fluid before it hardens and is poured into place. Formwork is used to mould the concrete into the desired shape.

Concrete reaches 75% of its compressive strength in 7 days and its finial testing strength in 28 days.

Concrete is an artificial stone. When cement is mixed with water it binds the sand and gravel aggregates to make concrete. It is usually 1 part cement, 2 parts fine aggregates, 4 parts coarse aggregates, and 0.4-­‐0.5 parts water. Too much water creates weak concrete and not enough water makes it unworkable.

CONCRETE SLAB

Properties Concrete is not completely waterproof so it needs sufficient cover or protection.

It is hard, durable and cost effective; it has low ductility and fragility and is medium-­‐high density. Concrete is not easy to recycle.

Reinforced Concrete

REINFORCED CONCRETE

Concrete is strong in compression but weak in tension. To improve the structural performance of concrete, steel (strong in tension) reinforcement in the form of mesh or bars is added.

Cantilevers Cantilevers are created when a structural element is supported at only one end or the overhanging portions of a member are significant.

The function is the same as a beam.

Cantilevers can be horizontal, vertical or angled.

IN SITU CONCRETE

In Situ Concrete In situ concrete is poured into framework and cured on site. There is limited time to cure the concrete before it hardens and becomes unworkable. Air bubbles are removed by vibrating the concrete. It is widely used in footing and retaining walls. Joints in concrete are potential weak points.

Concrete can sometimes be sprayed into place; this is useful for swimming pools and basement walls.

Construction joint – used to divide it into more manageable sections of work

Control joint – Required to absorb the expansions and contractions and the long-­‐term tendency for concrete to shrink.

IN SITU CONCRETE

Pre-­‐cast Concrete Pre-­‐cast concrete is manufactured (fabricated) in factories and transported to site. This allows for the work on site to progress faster and allows for more standardized outcomes. It can sometimes be a higher quality, as the climate doesn’t affect the setting of the concrete.

Using pre-­‐cast concrete usually means more joints need to be used, as the pieces need to be transported to site so they cannot be as big. The type of joint depends on the desired aesthetic outcome.

Pre-­‐cast concrete elements are often associated with the structure of a building and are generally used for retaining walls, walls, and columns.

CONCRETE PANELS

Pre-­‐cast concrete allows for a wider rang of finishes as it is made in a more controlled environment, but can be limited in size.

There are many benefits in using precast concrete. For example, the silicone formwork can be reused (cost effective) and it allows for repetition.

WEEK 5

From Wood to Timber

Early Wood: Has rapid growth at the beginning of the growing season. It has thin, large cells and a lighter colour.

Late Wood: Has slower growth, often limited by lack of water. It has thick, small cells and a darker colour.

It gives the growth ring.

Structural Nature of Wood

The direction of the grain of the wood determines the strength, stiffness and structural performance of the wood. It is generally stronger along, or parallel to the grain.

WOOD GRAIN

Wood to Timber

Seasoning or drying strengthens the timber by removing water to less than 15%. This provides increased dimensional stability.

It can by done by air seasoning that can take from 6 months up to two years but is very cheap or by kiln seasoning that can take from 20-­‐40 hours and is much more common.

SOFT WOOD

Soft Wood – Conifer Species Radiata Pine, Cypress Pine, Hoop pine, Douglas Fir

Hard Wood – Includes all Eucalyptus Species Victorian Ash, Brown Box, Spotted Gum, Jarrah, Tasmanian Oak, Balsa Wood (not a eucalyptus species)

Timber Properties Medium-­‐low hardness (can be easily marked), medium-­‐low fragility (geometry dependant), low ductility, high flexibility, medium plasticity, density can be low or high (depending on type) very durable (can vary depending on type), high reusability, generally sustainable and cost effective.

HARD WOOD

KNOTS

Timber is graded according to its strength. This is used to determine the size of timber needed to support certain loads. Some pieces of timber will be stronger in some points than others, but it is given the grade for the lowest strength it has.

Knots in timber create weak points as it causes a slope in the grain.

Timber can be damaged by water and sunlight. Fungal attacks often occur when the moisture is >20% and water/lack of water can cause swelling/shrinking resulting in cracks.

Direct sunlight can cause excessive drying (fire hazard) and insect attacks. The best way to protect it is to avoid exposure to weather or seal it (often done by painting).

DAMAGED TIMBER

Plywood: Made by gluing and pressing thin laminates together in alternate directions to form a sheet giving two-­‐way strength. Used for floors and bracing/joinery.

MDF: Made by breaking down wood waste into fibers and combining them with wax and resin. It is more dense than ply wood and is used for non-­‐structural applications.

Chipboard and Strandboard:

CHIPBOARD

Made by layering wood residual (chips and strands) in specific orientations with wax and resin and applying high temperatures and pressure. Can be used as part of structural systems such as flooring and cladding finishes.

LVL:

Laminated Veneer Lumber is made from laminating thin sheets of timber with the grain aligned in a longitudinal direction. Very deep and long sections can be made and it has a very high strength. It is often used in structural systems as posts or beams.

GLULAM: Glue laminated timber is made by gluing pieces of sawn timber together (in a longitudinal direction). Often used in structures.

CLT: Cross Laminated Timber is made by gluing and pressing thin laminates together in alternate directions to form a sheet. It provides strength in two directions and is often used as structural panels.

Walls

Walls are used to enclose and separate buildings/rooms, protect the interior from the exterior, insulate, moderate climate and filter out light.

They can be a major structural component and part of the structural system (carry loads).

Structural Frames: Concrete

frames (big city buildings), Steel frames (industrial buildings), Timber frames (post and beam).

Load Bearing Walls: Concrete (many new apartment buildings), Masonry (bricks, etc).

Stud Walls: Light gauge steel

LOAD BEARING WALLS

framing, timber framing (very common in housing).

Concrete Frames: Typically use a grid of columns with concrete beams connecting them.

Steel Frames: Typically use a grid of steel columns connected by steel girders and beams.

Post and Beam/Timber: Typically uses a grid of posts or poles connected to timber beams. Bracing is required to stabilize the structure.

TIMBER FRAMING

Load Bearing Concrete: This can be

achieved using in-­‐situ or precast concrete. The load bearing panels may also provide support for spandrel panels over and link into other structural elements (floor slabs, roof structure, etc).

Masonry: Can be solid or reinforced

LOAD BEARING MASONRY

Metal and Timber Stud Framing Framed walls use smaller sections of framing timber or light gauge steel framing to meet the structural demands of the construction.

Noggins (restraining) prevent long pieces of timber buckling while bracing (cross, diagonal and sheet bracing) is used to prevent the wall from tipping/twisting.

with steel. It is usually made from clay bricks or concrete units.

TIMBER STUD FRAMING

WEEK 6

Roofs are the primary shelter for

ROOF

buildings; they collect rainwater and come in many different forms.

Flat Roofs: have a pitch of 1-­‐3 degrees. If they are completely flat a pond can form increasing the load and causing damage.

Pitched and Slopping Roofs: have a pitch greater than 3 degrees.

Tiles should be pitched at >15°

Concrete Roofs

Concrete roofs are generally flat plates of reinforced concrete (or pre-­‐ cast slabs with a topping of concrete). The top surface is sloped towards drainage points and the entire roof surface finished with applied waterproof membrane.

Structural Steel Framed Roofs Flat steel roofs consist of a combination of primary and secondary roof beams or roof beams and purlins.

Sloping steel roofs consist of beams and purlins and light sheet roofing.

Portal Frames consist of a series of braced, rigid frames with purlins for the roof and grits for the walls.

GABLE ROOF

Light Framed Roofs

Trussed Roofs

Gable Roofs are characterized by a vertical, triangular section with a wall at one or both ends of the roof.

Made from timber/steel it consists of common rafters, ridge beams and ceiling joists.

Hip roofs are similar but also consist of hip rafters, valley rafters, and jack rafters.

Framed roofs constructed from a series of open web type steel or timber elements. Trusses are manufactured to be able to span long distances. The roofing material selected and the functional requirements of the roof often determine the shape of the element.

ROOF TRUSSES

Metals Ferrous – Iron (common and cheap)

Non-­‐ferrous – All other metals (generally more expensive and less common)

Alloys – Combinations of two or more metals

Properties Metals generally have low fragility, high ductility, medium-­‐high flexibility, high plasticity (while heated), high density, good conductivity, high durability and reusability and are cost effective.

Their hardness is varied depending on the type.

METAL

RUSTY METAL

Water Related Damage Oxidation and Corrosion – Metals ions can react with oxygen forming and oxide that can either protect the metal or result in corrosion (rust).

To protect them from corrosion metals should be sealed by enamel or paint, treated chemically (galvanized) or avoid prolonged exposure to moisture.

CORRUGATED IRON

Ferrous Metals Iron: Iron is magnetic, very reactive chemically (easily corrodes) and has good compressive strength.

Wrought Iron: Heated and hammered into desired shape, expensive. (bars/decorative element)

Cast Iron: Melted and poured into moulds with high compressive strength.

Iron Alloys

STEEL

Steel is an alloy of iron with carbon being the primary additional alloy element. It is strong, transfers heat and electricity well, comes in many different shapes and is long lasting.

Steel Sheeting can be used for cladding/roofing but must be protected from weather exposure.

Structural Steel Used for framing, columns, purlins, beams and stud frames.

Hot Rolled steel elements are shaped while hot, use more material and are used for primary structural elements. Cold Formed steel elements are folded from sheet that have been previously produced and used for secondary elements.

Stainless Steel Alloys

STAINLESS STEEL

Chromium is the main alloying element with no less that 12%. It is made into coils, sheet, plates, bars, wires and tubing and is generally used in harsh environments such as kitchens or operating rooms. It is very rarely used in primary structural elements.

Non-­‐Ferrous Metals

Aluminium: Is light, easily formed, expensive and used for handrails, door handles, window frames and cladding

ALUMINIUM

Zinc: Is used to galvanize steel/iron and as cladding

Lead: Is soft and ductile, is a poor conductor of electricity and isn’t very common and it can be poisonous when in contact with water/ingested but was used in roofing/tank lining

ZINC CLADDING

Titanium: Is used in strong,

TIN

lightweight alloys, used for cladding and can resist corrosion. It is light, strong and expensive

Tin: Is very rare in construction, but can often be seen in decorative elements

BRASS

Bronze (copper + tin): Is tough, hard, corrosion resistant and used in bearings, springs and clips

Brass (copper + zinc): Has a low melting point, is easy to cast and is used for locks, gears, screws, valves, and fittings

Copper: Is a good conductor of electricity, very ductile and was traditionally used as roofing material but is now seen in water/heating pipe work and electric cabling

COPPER

WEEK 7

Detailing For Heat and Moisture

For water or air to penetrate into a building all of the following must occur.

-­‐ An opening -­‐ Water/air present at the opening -­‐ A force to move the water/air through the opening

WINDOW SILL TO KEEP WATER AWAY

To prevent water penetrating into a building, three different strategies are employed.

-­‐ Remove openings OR -­‐ Keep water away from openings OR -­‐ Neutralise the forces that move water through the openings One is sufficient but if two or more strategies are pursued there is added security in case one fails.

Openings can be:

Planned elements such as window, doors, skylights, etc.

OR Unplanned openings in the building fabric created by poor construction workmanship or deterioration of materials.

SKYLIGHT

Keeping Water From Openings

Water can be directed away from openings by: -­‐ Grading (sloping) roofs -­‐ Overlapping elements (eg roof tiles) -­‐ Sloping window and door sills -­‐ Sloping ground surfaces Neutralising Forces This is done by using overlaps and slopes so gravity moves the water

Techniques To Remove/Seal Openings

SILICONE SEAL

-­‐ Sealants (e.g. silicone) -­‐ Gaskets (e.g. preformed shapes made from artificial rubbers, etc)

Both techniques rely on correct installation and will deteriorate over time due to weathering

ROOF INSULATION

Controlling Heat -­‐ Heat gain and heat loss occur when: Heat is conducted through the building envelope -­‐ The building envelope/elements are subjected to radiant heat sources -­‐ Thermal mass is used to regulate the flow of heat through the building envelope Effective control saves energy/money

Heat Conduction can be controlled by:

INSULATION

-­‐ Thermal Insulation (reduce heat conduction) -­‐ Thermal Breaks (rubbers and plastics used to reduce heat transfer) -­‐ Double Glazing (air space between glass reduces the flow of heat)

Radiation can be controlled by

reflective surfaces (less heat absorbed) and shading systems (stop radiation striking the building).

Large areas of Thermal Mass can be used to absorb and store heat over time. When temperatures drop the stored heat is released. Materials used include masonry, concrete and water bodies.

Controlling Air Leakage

Strategies to stop air leakage and heat gain/loss include eliminating openings and the forces that move the air through the openings as well as adding weather stripping around doors, windows, etc.

RUBBER DOOR SEAL

RUBBER

Rubber can be natural (sourced from a rubber tree) or synthetic (synthesized in a lab – technically a plastic).

Rubbers can lose their properties when exposed to weather, especially sunlight.

Types and Uses

Natural – Used for seals, gaskets, flooring, insulation, hosing and piping.

Synthetic – EPDM (gaskets), Neoprene (control joints), Silicone (seals)

WINDOW SEAL

Properties

Rubbers have low fragility, high ductility, high flexibility/plasticity, poor conductor, varied hardness (hard resists abrasions, soft provided better seals), very durable, high reusability and are generally cost effective.

PLASTICS Thermoplastics – mouldable when heated, become solid when cooled.

E.g. Polyethylene, poly(methyl methacrylate), polyvinyl, polycarbonate.

PLASTIC OUTDOOR ROOFING

Thermosetting Plastics – can only be moulded once. E.g. Melamine Formaldehyde (laminex), Polystyrene (insulation panels)

Elastomers – Synthetic Rubbers

Properties Medium-­‐low hardness and fragility, high ductility, high flexibility/ plasticity, low density, poor conductors, very durable, high reusability (except thermosetting), generally cost effective.

Considerations

Weather related damage Plastic properties degrade when exposed to weather (especially sunlight) and need to be checked and maintained.

Protection Avoid exposure to weather when possible.

DAMAGED PLASTIC

PAINTS

Paints are liquid until they are applied to a surface forming a film that becomes hard 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 (polyurethanes, polyesters, resins, oils)

Diluents – dissolves the paint and adjusts the viscosity (alcohol, petroleum, distillate, esters)

Pigment – gives the paint colour and opacity. Can be natural (clays, calcium, carbonate, etc) or synthetic

MATT GLOSS FINISH FINISH

Types and Uses Oil Based – Used prior to plastic paints (water based), high gloss finishes can be achieved, not water soluble (turpentine needed to clean brushes).

Water Based – Most common today, durable and flexible, tools and brushes can be cleaned with water.

WEEK 8

Doors and Windows allow light, insulation, views and access. They can be timber, aluminum (common in commercial and office buildings), or steel (used for security purposes).

Curtain Walls are hybrid systems that act as windows and a wall that carries its own load and transfers loads to the concrete structure.

Glass

History

Formers – the basic ingredient that can

1 century BC – Brown Glass

be melted and cooled to produce glass.

11-­‐13th centuries – Sheet Glass (sliced

E.g. Silica

from brown glass)

Fluxes – help formers to melt at lower,

17th century – Lead Crystal (easier to cut)

more practical temperatures. E.g. Soda

17th century – Plate Glass (improved

ash, potash, lithium, carbonate

optical qualities)

Stabilizers – combine with formers/

1910 – Lamination

fluxes to keep the finished glass from

1959 – Float Glass (molten glass is

dissolving or crumbling. E.g. Magnesia

poured over a bath of molten tin)

Glass Properties

Waterproof, medium-­‐high density, transmits heat and light but not electricity, very hard, high fragility, low ductility, high flexibility and plasticity when molten but low when cooled, very durable, very high reusability and recyclability, generally expensive to produce and transport.

Flat Glass – typically sheets of clear or tinted float, laminated, tempered, wired, etc

Shaped Glass – curved, blocks, channels, tubes, fibers

Float Glass – now the most common glass production process in the world

ANNEALED GLASS

Clear Float Glass (annealed glass)

The simplest and cheapest glass product available in the market. No further treatment beyond the float fabrication.

Ideal in low risk, low cost, small size glazing scenarios. Breaks into very sharp and dangerous shards.

Laminated Glass

A tough plastic interlayer (PVB) is bonded together between two glass panes.

This improves the security and safety of the glass product, as even though the glass can still crack, the sharp fragments tend to adhere to the plastic rather than falling apart.

TEMPERED GLASS (shower screen)

Tempered Glass (toughened glass)

Produced by heating annealed glass to approximately 650°C, at which point it begins to soften. The surfaces of this heated glass are then cooled (quenched) rapidly creating a state of high compression in the outer surfaces of the glass.

↓ continued…

As a result the bending strength is increased by a factor of 4-­‐5 times that of annealed glass and makes it break (shatter) into small, pallet shaped pieces rather than sharp shards, improving the safety of the product.

Ideal to used in highly exposed situations (e.g. Facades) or when the size required is particularly large.

WEEK 9

Construction Detailing

-­‐ Movement Joints -­‐ Health and Safety (fire, stairs, ramps) -­‐ Ageing Gracefully (deterioration/decay) -­‐ Repairable Surfaces and Resistance to Damage -­‐ Cleanable Surfaces Constructability

Ageing Copper

Monolithic Materials A single material or materials combined so that components are indistinguishable (e.g. metal alloys).

Composite Materials Created when two or more materials are combined in such a way that the individual materials remain easily distinguishable.

Composite Materials A composite is formed from a: -­‐ Combination of materials that differ in composition or form -­‐ Remain bonded together -­‐ Retain their identities/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 different forms but can be grouped into four main types

-­‐ Fibrous (fibers) -­‐ Laminar (e.g. sandwich panels) -­‐ Particulate (e.g. gravel and resins) -­‐ Hybrid (combinations of two or more composite types)

Fiber Reinforced Cement

FIBERGLASS BATH

Common forms are sheet and board products, pipes and roof tiles. It is water and termite resistant and will not burn, rot or warp.

Fiberglass Used for transparent/translucent roof and wall cladding, pools, baths, etc. It is fire resistant, weatherproof, lightweight, and strong.

TIMBER COMPOSITES (POSI-­‐TRUSS)

Aluminium Sheet Composites Generally come in a honeycomb sheet lined with two external skins of thin aluminium. It is lightweight, unbreakable and weather resistant.

Timber Composites Solid and engineered timber with galvanized steel used for beams and trusses. Min material used for max efficiency and cost effective.

SITE VISIT

KANE Construction’s project in Melbourne’s CBD consists of adding six new levels on top of the 19 floor Owen Dixon Chambers West building.

The building required a tower crane to be positioned on the existing roof with works being undertaken while the building remained occupied.

The structure is formed from a steel frame, concrete and a curtain wall.

In this image part of the frame has been sprayed with fire-­‐rated protection to make sure the building receives the minimal amount of damage and can last longer in the case of a fire.

This image shows part of the newly installed curtain wall. The panels are lifted into place by the crane and the crew then fixes them into place.

The walls in the building are a structural steel frame with beams along the top and bottom and posts positioned vertically. The posts bend quite easily however when fixed in place properly and the walls and plaster are finished they are a lightweight and strong element.

Hebel flooring was used as it provides superior strength, thermal and acoustic properties in a load bearing modular solid aerated concrete flooring system while being lighter in weight than normal concrete panels. This is significant because of the height of the building and load it can support. The hebel is reinforced with steel for strength.

Like the walls, the roof framing is also made from steel. It consists of many different sized beams and trusses. The steel frame supports the roof as well as the hebel flooring and suspended ceilings on other floors.

WEEK 10

Collapses and Failures

Failures can be caused by a variety of different things such as corrosion, warping, twisting, cracking and breaking. This can be caused by exposure to weather and sun, water related damage, unexpected high loads and many other things.

When thinking about design we should choose materials that help to keep a safe and unpolluted environment. We should choose natural and organic materials that will last longer and can be reused to minimize embodied energy, pollution, environmental impact, energy use and waste. We should design for purpose and durability.

CONSTRUCTION WORKSHOP

In our construction workshop we were given two long pieces of plywood and two pieces of pine to make a beam that would span one meter and withstand a point load.

We used one piece of pine as a long beam with one piece of pine attached on each side for extra support as well as smaller pieces of pine in between.

The point load applied to our beam was a big block of wood.

Our beam deflected 38 centimeters and held a load of approximately 300 kilograms before the plywood on each side cracked.

Glossary

Noggin – A horizontal element inserted between

wall studs for strength Brace – Serving to brace (support) a structure

Parapet – A low protecting wall along the edge of Column – An upright, cylindrical pillar that a roof, bridge or balcony supports part of a structure

Point Load – A load which is localised to a specific Compression – The action of compressing or location on a structure being compressed

Purlin – A horizontal beam along the length of the Eave – The part of a roof that meets or overhangs roof the walls of a building

Rafter – A beam forming part of the internal Flashing – A metal strip used to stop water framework of a roof penetrating the junction of a roof with another

surface Retaining Wall – A wall that holds back earth or

water Footing – The supporting base or groundwork of a structure Shear Force – Unaligned forces pushing one part

of an element in one direction and another part in Frame – An open structure that gives shape and the opposite direction support to something

Skirting – A wooden board running along the base Joist -­‐ A length of timber or steel supporting part of an interior wall of the structure of a building, typically arranged

in parallel series to support a floor or ceiling Span – The space or distance between two points

Lintel – A horizontal support across the top of a Stability – The state of being stable door or window

Stress – Pressure or tension exerted on a material Load Path – A path that forces pass through to object the foundations of a structure

Stud – An upright wall framing element Masonry -­‐ The building of structures from

individual units laid in and bound together by Substructure – An underlying or supporting mortar; the term masonry can also refer to the structure units themselves

Tension – A force that tends to stretch an element

References

-­‐ Weekly e-­‐Learning for Constructing Environments, 2014, http://issuu.com/envs10003

-­‐ Constructing Environments Lectures, 2014

-­‐ Francis D.K. Ching, Building Constructed Illustrated, Fourth Edition, 2008