WEEK 1 Construction Overview
Key idea-----how the design ideas get translated into the built form Learning ways: o Experimentation o Observation o critique What is responsible? 1. structural principles----the way that the buildings are supported how loads are transported to the ground 2. materials 3. cranes & labour 4. basic science & engineering principles (tension compression, bending torsion & standard construction techniques)
Materials Introduction
strength: weak/strong stiffness: stiff/flexible/stretchy/floppy shape: mono-dimensional(linear)/bi-dimensional(planar)/tridimensional(volumetric) material behaviours: isotropic/anisotropic sustainability & economy
Melbourne’s bluestone (basalt—from volcano) Lane:
wheel ruts water damage & impact damage from trucks stiletto heels damage
Flinder Street:
modern bluestone damaged by modern vehicles
Sydney-----sandstone Perth----clay for bricks & limestone
Basic Structural Forces A FORCE is any influence that produces a change in the shape or movement of a body
Ching ‘Building Construction Illustrated’ – Page 2.11
-Tension forces stretch and elongate the material When an external load pulls on a structural member, the particles composing the material move apart and undergo tension.
Lecturer: Clare Newton
-COMPRESSION FORCES produce the opposite effect of a tension force When an external load pushes on a structural member, the particles of the material compact together.
Lecturer: Clare Newton
Load Path Diagrams The applied loads have a reaction which means that the whole structure is stable.
https://www.youtube.com/watch?v=y__V15j3IX4&feature=youtu.be
TUTORIAL ACTIVITY—BUILD A TOWER AS TALL AS POSSIBLE At first, we made a square foundation, leaving a half-brick space between each bricks.
Then, to build a closed tower, we make the square into a circle.
At last, we decided to make a gate, so we put the bricks one by one as close as possible to avoid the tower being damaged. Not very stable and beautiful is the gate…
SUMMARY: we need to plan well before we build something because not any time we can succeed by accident like this. We didn’t mean to turn the square foundation into a circle…only because we want a closed tower during the constructing. Therefore, our tower didn’t have a particular style and a beautiful looking, although we call it abstract by ourselves. Also we didn’t need to build a gate. A much easier way is just pulling some bricks out after we build a stable tower.
Week 2 Key terms
Structural joint Stability Tension Frame Bracing Column
CHING: 02 the building (2.02_2.04) BUILDING SYSTEM
Structural system the superstructure-----the vertical extension of a building above the foundation columns, beams, and loadbearing walls support floor and roof structures the substructures----the underlying structure forming the foundation of a building. Enclosure system o Shelter interior spaces o Dampen noise and provide security & privacy o Doors provide physical access o Windows provide access to light, air and views o Interior walls subdivide the interior of a building into spatial units Mechanical system The water supply ----human consumption and sanitation The sewage disposal system Heating, ventilating and air-conditioning systems The electrical system Vertical transportation systems Fire-fighting systems Recycling systems
Factors should be taken into consideration
Performance requirements Aethelic qualities Regulatory constraints Economic consideration Environmental impact Construction practice
ESD and SELECTING MATERIALS
CONSTUCTION JOINTS ROLLER JOINTS Transfer loads only in one direction
PIN JOINTS
FIXED JOINTS
STUDIO TASK “FRAME”
W03
A slender element design to carry load parallel to its long axis. The load produces compression.
Tension
SLAB/PLATE: A wide horizontal element designed to carry vertical load in bending usually supported by beams.
A horizontal element designed to carry vertical load using its bending resistance.
Panel: A deep vertical element designed to carry vertical or horizontal load.
Hardness
Bricks Medium-high
Blocks Medium-high
Fragility
medium
medium
Ductility Flexibility/plasticity Porosity
Very low Very low Medium-low
Durability Recyclability Density Conductivity sustainability
Very durable High Medium poor Tends to be locally produced. The firing process adds to its carbon footprints.
cost
Labour cost
Very low Very low Medium-low (some concrete blocks are sealed to reduce the opportunities for water absorption) Very durable medium Medium poor Inclusion of recycled & waste products from other processes is allowing a positive reduction in carbon footprint and increase in sustainability for many concrete products. Labour cost
stone Igneous>metamorp hic>sedimentary Geometry dependent Low Very low Large range (pumice is very porous, granite is not.)
Extremely High Large range Poor High environment cost, transport cost (local stone have low carbon footprints)
Depend on labour and scarcity
A
brick is a standard size masonry unit made out of clay. 3 main types: Extruded and wire-cut Machine moulded (pressed) Handmade (convict-made) USES: walls, arches & paving JOINTS-mortar joints-10mm-perpends (vertical) -horizontal (horizontal) Advantages:
Can be joined with water base mortar. Adequately ventilated-any wetness can escape, will not deteriorate. Disadvantages: Absorb moisture and expend overtime-expansion joints required. Salts and lime from the soil can be drawn up through the bricks when contact in the grounserious pathologies /& aesthetic problems such efflorescence.
A concrete
block is a standard size masonry unit made out of concrete.
-are manufactured from cement, sand, gravel & water. USES-walls-load bearing (structural) -non-loading bearing (dividing & decorative walls)
Concrete shrinks overtime while clay bricks will expand. Movement joints are required for each material.
STONE TYPES-igneous (bluestone & basalt), sedimentary (limestone & sandstone) and metamorphic (marble /slate) USES-walls, paving, cladding, aggregates & feature design elements.
WALK AROUND CAMPUS
FRANK TATE PAVILION
http://www.timberawards.com.au/media/k2/items/cache/aaa036e4cb16038f90e128d8e39c714f_XL.jpg
https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=v6KpkqRBJIOX8M&tbnid=9_Ih8TqN0oE_DM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.findfood.c om.au%2F3010%2Funiversity-melbourne%2Flot-6&ei=mxt3U4m2EsX28QXQxoCQBQ&bvm=bv.66917471,d.dGc&psig=AFQjCNE5X4b8QgmWoCugLCheT_FITNoPUw&ust=1400401175764066
LOT 6 CAFÉ
UNDERGOUND CAR PARK
Bibliography https://www.youtube.com/watch?v=wQIa1O6fp98&feature=youtu.be https://www.youtube.com/watch?v=PAcuwrecIz8&feature=youtu.be Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008 Hunt, T., Tony Hunt’s Structures Notebook, Architectural Press, 2003 Vassigh, Shahin, InteracGve Structures Version 2.0, Wiley & Sons, Inc., 2008 DVD-ROM
FLOOR SYSTEMS AND HORIZONTAL ELEMENTS SPAN AND SPACING SPAN 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.
SPACING SPACING is the repeating distance between a series of like or similar elements. SPACING is often associated with supporting elements (such as beams, columns etc.) and can be measured horizontally or vertically. SPACING is generally measured centre-line to centre-line.
SPAN and SPACING SPACING of the supporting elements depends on the
SPANNING capabilities of the supported elements
BEAMS A BEAM is a (mostly) horizontal structural element. The function of a BEAM is to carry loads along the length of the beam and transfer these loads to the vertical supports. A BEAM can be: - supported at both ends of the beam - supported at numerous points along the length of beam - supported at points away from the ends of the beam (creating overhangs / cantilevers beyond the supports) - supported at only one end of the beam
CANTILEVERS A CANTILEVER is created when a structural element is supported at only one end (or the overhanging portions of a member are significant). The function of a CANTILEVER is to carry loads along the length of the member and transfer these loads to the support. A CANTILEVER can be: -horizontal -vertical -angled
FLOOR AND FRAMING SYSTEMS CONCRETE Slabs of various types are used to span between structural supports. These can be one-way or two-way spans.
TIMBER Timber floor framing systems combination of bearers (primary beams) and (secondary beams). The of the bearers determines the spacing of the or stumps and spacing of the bearers equals the span of the joists.
STEEL Steel framing systems take various forms, with some utilising heavy gauge structural steel members and other using light gauge framing. Sometimes combine with concrete slab systems to where the particular benefits of steel framing and shallow depth floor slab systems are desired. The spanning capabilities of the particular materials help to determine the spacing requirements of the support.
use a
joists span
piers the
CONCRETE A common concrete mix is 1 part cement, 2 parts fine aggregate, 4 parts coarse aggregate and 0.4~0.5 part water. PROCESSES:
HYDRATION (cement powder + water): -too much water –weak -too little water -unworkable
FORMWORK-hold the liquid concrete in place until it become hard CURING PROCESS-needs to be supported by using props and bracing of various types.
REINFORCED CONCRETE: concrete is very strong in compression but is weak in tension. To improve its structure performance, steel (very strong in tension) reinforcement in the form of MESH or BARS in added. COSIDERATIONS:
Aesthetic and structural degradation of the concrete. Concrete is permeable, which make the steel bars which too close to the surface cannot be protected from moisture and oxidation. The air bubbles compromise the structural performance of the elements and in a worst case scenario, resulting in the element failing.
PRE-CAST CONCRETE -is any concrete element that has been fabricated in a controlled environment and then transported to site for installation. -ensure a much more standardised outcome that avoids many of the quality control issues associated in situ concrete. -a much faster rate. USES: retaining walls, walls and columns. Rarely used in footings. CONSIDERATIONS: can be limited in size due to transport. On site changes are very difficult to incorporate.
KNOWLEDGE MAP
BIBILIORGRAPHY https://www.youtube.com/watch?v=scYY-MMezI0&feature=youtu.be https://www.youtube.com/watch?v=c3zW_TBGjfE&feature=youtu.be https://www.youtube.com/watch?v=otKffehOWaw&feature=youtu.be Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
W05 WALLS, GRIDS AND COLUMNS STRUCTURAL FRAMES -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 grid and beams -TIMBER FRAMES (POST AND BEAM) -typically uses a grid of timber POSTS or POLES connected to timber beams. -bracing of members between bays at the corners of post/ beam junction is required to stabilise the structure.
LOAD BEARING WALLS -CONCRETE 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 slabs, roof structure etc.). -MASONRY
REINFORCED MASONRY
REINFORCED MASONRY load bearing walls can be constructed from CORE FILLED hollow concrete blocks or GRID FILLED 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
SOLID MASONRY load bearing walls can be created with single or multiple skins of concrete masonry units or clay blocks. The skins of masonry are joined together using a block (with HEADER showing in face of wall) or with metal WALL TIES placed within the mortar bed.
CAVITY MASONRY
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 WALLS -LIGHT GAUGE STEEL 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. The 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 PLY BRACING. - TIMBER FRAMING
-BRICK VENEER CONSRUCTION Combinations of 1 skin of non-structural masonry and 1 skin of structural frame wall are widely used in the construction industry
FROM WOOD TO TIMBER
TYPES Different woods have different properties, which based on their biological provenance (and not based on their strength or density) SOFTWOODS In Australia common softwoods include all conifer species: -radiata pine -cypress pine -hoop pine -douglas tir HARDWOODS Native Australian hardwoods include all eucalyptus species: . Victorian ash . brown box . spotted gum . jorrah . Tasmanian oak . balsa wood (not an eucalypt nor an Australian timber but, surprisingly, a hardwood)
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 - cheap but slow - 6 months to 2 years per 50 mm thickness -kiln seasoning - typically 20-40 hours to dry to 12% -solar kiln seasoning - less expensive to run
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 to coatings -lower width shrinkage on drying -less cupping and warp than other cuts -can be successfully reconditioned Disadvantages -slower seasoning -nailing on face mare 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
SHORT AND LONG COLUMNS COLUMNS are vertical structural members designed to transfer axial compressive loads. ALL columns are considered SLENDER MEMBERS and for axial loads, they can be classified as either the SHORT or LONG. SHORT COLUMNS are shorter (length) and thicker (cross-section). LONG COLUMNS are taller (length) and slimmer (cross-section). LONG COLUMNS
Columns are considered long if the ratio of effective column length to the smallest cross section dimension is greater than 12:1. For example: a 6000mm tall column with a 450mm x 300mm cross-section will have a ratio of 20:1. Therefore it would be considered a long column. Long columns become unstable and fail by buckling. The shape of the 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 of the different fixing methods. The effective length is measured between the points of contraflexure.
Short columns Columns are considered short if the ratio of effective column length to the smallest cross section dimension is less than 12:1. For example: a 3000mm tall column with a 450mm x 300mm cross-section will have a ratio of 10:1. Therefore it would be considered a short column. 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).
Engineered Timber Products TIMBER-PROPERTIES-can greatly differ depending on type. Generally: -medium-low hardness. Most timbers can be seasonably easily marked. -medium-low fragility. Geometry dependent, generally will not shatter or break. -low ductility. Some timbers in their green state can be manipulated in to a range of shapes. -high flexibility and medium plasticity. -high porosity. Varies depending on seasoning, finishing (protection) and fixing. -density extremely varied depending on timber type. -poor conductor of heat and electricity -can very durable. Varies depending on type, seasoning, finishing (protection) and fixing. -very high recyclability. Second hand timber is very desirable. -very low embodied energy. Fully renewable if correctly sourced. -generally cost effective. Labor dependent for on-site work. But also suited to highly efficient factory based manufacturing processes. 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 6.0 m - 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 DURABUTY -GOOD PRACTICE WATER related DAMAGE fungal attack often occurs when moisture content of wood >20% swelling, shrinkage con cause cracks PROTECTION against water avoid exposure (when possible) seal against moisture movement â&#x20AC;&#x201C; point particular care is needed with end grain - seal 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 USES-mainly structural (beams, post, 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 USES-mainly structural (beams, post, portal frames) CLT - CROSS LAMINATED TIMBER Made by gluing and pressing thin laminated together to form a sheet, laminate grain laid in alternate directions (90 degrees), provides strength in two directions. USES - structural panels (horizontal and vertical)
ENGINEER TIMBER - SHEET PRODUCTS PLYWOOD - made by gluing and pressing thin laminated together to form a sheet, grain in laminated in alternate directions strength in two directions. USES - 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 was and a resin binder by applying high temperature and pressure. MDF is generally more dense than plywood. USES - non-structural applications (joinery)
CHIPBOARD & STRANDBOARD Made by layering hardwood or softwood residuals (chips, strands) in specific orientations with was 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 rationable 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
ACTIVITY----------STRUCTURAL CONCEPTS We used cardboard to make loading wall for the lower level and used sticks to build the frame on the upper floor. The scale is 1:200. We use tapes and glue to connect the joints, which make it like a flexible frame. Also it seems too flexible and fragile, so that it cannot bearing too much.
BIBILIORGRAPHY Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘Walls, Grids and Columns’ http://www.youtube.com/watch?v=Vq41q6gUIjI&feature=youtu.be Clare Newton, ‘From Wood to Timber’ http://www.youtube.com/watch?v=YJL0vCwM0zg&feature=youtu.be Clare Newton, ‘Timber properties and considerations’ http://www.youtube.com/watch?v=ul0r9OGkA9c&feature=youtu.be Clare Newton, ‘Engineered Timber Products’ http://www.youtube.com/watch?v=0YrYOGSwtVc&feature=youtu.be
W06 SPANNING AND ENCLOSING SPACING TRUSSES -A truss is a structural frame based on the geometric rigidity of the triangle and composed of linear members subject only to axial tension or compression.
FOOTING STRATEGIES AND SYSTEMS ROOF SYSTEMS -FLAT ROOFS (PITCH: 1째~3째) -PITCHED AND SLOPING ROOFS (PITCH: >3째)
CONCRETE ROOFS: Are generally flat PLATES of reinforced concrete (or precast slabs with a topping of concrete). The top surface is sloped towards drainage points and the entire roof surface finished with applied waterproof membrane.
TRUSSED ROOFS: TRUSS roofs ore framed roofs constructed from a series of OPEN WEB type steel or timber elements. Trusses are manufactured from steel or timber components. Fixed together to form efficient elements able to span long distances.
The shape (slope) and material of the structural elements is often determined by the roofing material selected and the functional requirements of the roof.
STRUCTURAL STEEL FRAMED ROOFS: FLAT structural steel roofs consist of o combination of primary and secondary ROOF BEAMS for heavier roof finishes such as metal deck/ concrete; or ROOF BEAMS and PURLINS for lighter sheet metal roofing. SLOPING structural steel roofs consist of ROOF BEAMS and PURLINS and lighter sheet metal roofing. PORTAL FRAMES consist of a series of braced RIGID FRAMES (two columns and a beam) with PURLINS for the roof and GIRTS for the walls. The walls and roof ore usually finished with sheet metal).
SPACE FRAMES: Are 3D PLATE type structures that are long spanning in two directions. Linear steel sections of various cross section types are welded, bolted or threaded together to form matrix-like structures.
LIGHT FRAMED ROOFS: GABLE ROOFS are characterised by a vertical, triangular section of wall at one or both ends of the roof. The roof consists of COMMON RAFTERS, RIDGE BEAMS and CEILING JOISTS. Where the roof overhangs the gable end wall OUTRIGGERS ore used. MATERIALS timber cold-formed steel sections (and also sometimes heavier steel (UB or PFC) for major beams).
HIP ROOFS are characterised by a vertical, triangular section of wall at one or both ends of the root. The roof consists of COMMON RAFTERS. HIP RAFTERS. VALLEY RAFTERS. JACK RAFTERS, RIDGE BEAMS and CEILING JOISTS. MATERIALS timber, cold-formed steel sections.
METALS METALS â&#x20AC;&#x201C; TYPES FERROUS (from Latin, ferr(um) = iron): IRON is the fourth most common element in the Earth (relatively cheap) NON-FERROUS: All other metals -Generally me expensive (less common). Less likely to react with Oxygen (to oxide) and superior working qualities. ALLOYS-Combinations of two or more metals (ferrous alloy if it contains iron, non-ferrous alloy if it does not)
METAL-ROPERTIES -can greatly differ depending on type. Generally: -hardness depending on type. (Lead is very easy to scratch, gold is not) -low fragility. Generally will not shatter or break. -high ductility. Due to their atomic composition -medium-high flexibility and high plasticity while heated -generally impermeable. Used for guttering, flashing etc. -high density -very good conductors of heat and electricity. -can very durable. Depending on type, treatment, finishing and fixing. -high recyclability -very high embodied energy. Recyclable and renewable if correctly managed. -generally cost effective.
CONSIDERATIONS Metals will react with other metals by giving up/taking on another metal's ions.
Ion transfer will happen when the metals ore directly in contact with each other or they are in an environment (water/moisture) that facilitates the transmission of the ions (electrolysis). WATER related DAMAGE Oxidation and corrosion. Metal ions can react with oxygen forming on oxide which can sometimes protects the metal but in other instances it can result in the corrosion of the metal. Aluminium oxidises to form a protective layer. Rusty steel is an example of undesirable corrosion. PROTECT against water to reduce corrosion -avoid prolonged exposure to moisture (eg crevices and flat horizontal surfaces) -seal against moisture (eg enamel or point metal surfaces) -chemical treatment (i.e. galvanised steel)
IRON - DISTINCTIVE PROPERTIES Significant and important MAGNETIC properties VERY REACTIVE chemically (easily corrodes through rusting) Good COMPRESSIVE strength -IRON - TYPES & USES Wrought Iron Used from circa 1000BC. Wrought won is formed when Iron is heated and hammered into the desired shape. In construction it was widely used in bars for windows and doors and for decorative elements. Still used today (but is expensive as it is labour intensive). Cost Iron Widely used in the 19th century and the beginning of the twentieth century. Cost iron is formed when iron is melted and the molten (liquid) metal is poured into moulds to cool. As port of this process. Cast iron acquires a very high compressive strength. Very rarely used in contemporary construction due to its weight and brittleness. Is generally only used for compression elements (e.g. columns). Is still found in older buildings and mode to order for restored constructions.
IRON ALLOYS - STEEL Steel is an alloy of IRON with CARBON being the primary additional alloy element. Other alloying elements include manganese. Chromium, boron and titanium among others. Different proportions and combinations result in different types of steel, where each type has slightly different properties.
STEEL - DISTINCTIVE PROPERTIES Very STRONG and resistant to fracture Transfers HEAT and ELECTRICITY Can be formed into MANY DIFFERENT SHAPES (from wires to panels to beam and columns) LONG LASTING and resistant to wear (if properly protected) - TYPES AND USES 1. STRUCTURAL steel FRAMING - columns, beams, purlins, stud frames. We will refer to different 'steel sections' or profiles depending on the shape of the structural element. There are two main types: - Hot rolled steel - Elements are shaped while metal is hot. More material is required for this type of process. Generally used as PRIMARY structural elements - Often protected from rusting and corroding by coatings (paint or hot dipped galvanising) - JOINTS are WELDED or BOLTED - Cold formed steel - Elements ore FOLDED from SHEETS that have been previously produced and cooled down. Used as SECONDARY structure - Protected by hot dip processes (GALVANISATION) JOINTS are BOLTED or SCREWED - REINFORCING BARS - Due to its good TENSILE resistance, steel is used in conjunction with concrete to produce reinforced concrete. Deformations on the bars assist bonding with the concrete.
2. Steel SHEETING CLADDING and ROOFING (corrugated iron or other sheet profiles) - must be protected from weather exposure (PAINT, ENAMELLED FINISHES, GALVANISATION) 3. STAINLESS steel alloys - Chromium is the main alloying element (minimum 0112%) - The alloy is milled into coils, sheets, plates, bars, wire, and tubing. Generally used harsh environments or where specific inert finishes are required (e.g. kitchens, operating rooms etc.) Wall ties in cavity walls are often made from stainless steel due to its corrosion resistance. - Stainless steel is very, very rarely used as primary structure due to cost (only in harsh environments)
ALUMINIUM - DISTINCTIVE PROPERTIES Very LIGHT compared to other metals Non-magnetic and non-sparking Easily formed, machined and cast Pure aluminium is soft and lacks strength, but alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties (including STRUCTURAL CAPABILITIES). - 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 o very fine layer of oxide that keeps it horn further oxidation giving it that matte natural finish. Other finish treatments con 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 o 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) - USES Traditionally used as ROOFING MATERIAL, 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 150CC. 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 o 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: Tin extraction and use can be doted to the beginnings of the Bronze Age around 3000 B.C. where it added to copper to make Bronze Present use in construction: Very rare today (generally only decorative). Tin was used in building for lining lead pipes (TOXIC), and occasionally as a protective covering for won plates and for small gas pipes I 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 top water, but is attacked by strong acids, alkalis, and acid salts. Oxygen in solution accelerates the attack.
TITANIUM History: Titanium was discovered in Cornwall, England, in 1791 by amateur geologist and pastor William Gregor. Starting in the early 1 950s, titanium began to be used extensively for military aviation purposes, particularly in high-performance jets. 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 as 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 'pillowy' 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. 2000 BC) Present use in construction: Bronze parts ore tough and typically used for bearings, clips, electrical connectors and springs. Bronze was often used for external applications, 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 cost. It is not ferromagnetic.
Bibliography:
Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘Introduction to Metals’ https://www.youtube.com/watch?v=RttS_wgXGbI&feature=youtu.be
Clare Newton, ‘From Wood to Timber’ http://www.youtube.com/watch?v=YJL0vCwM0zg&feature=youtu.be
Clare Newton, ‘Ferrous Metals’ https://www.youtube.com/watch?v=SQy3IyJy-is&feature=youtu.be
Clare Newton, ‘Non Ferrous Metals’ https://www.youtube.com/watch?v=EDtxb7Pgcrw&feature=youtu.be
W07 Detailing Strategies 1 Detailing for Heat & Moisture Detailing For Moisture For water to penetrate into a building all of the following three conditions must Occur: -An opening -water present at the opening -a force to move water through the opening Remove any one of the conditions and water will not enter.
Three different strategies: -remove openings -keep water away from openings -neutralise the forces that move water through openings One is sufficient but if two or more strategies are pursued then there is added security in case on fails. Openings can be: Planned elements such as windows, doors, skylights etc. Unplanned openings in the building fabric created by: -poor construction workmanship -deterioration of materials -remove opening Common techniques used to remove openings to prevent water penetration Include seal the openings with: -sealants (e.g. silicone) -gaskets (e.g. preformed shapes made from artificial rubbers etc.) Both sealants and gaskets rely heavily on correct installation and will deteriorate over Time due to weathering. -keep water away from openings is a commonly used strategy construction detailing This means that water is directed away from any potential openings in the building by: Grading (sloping) roofs so that the water is collected in GUTTERS which then discharge the water to DOWNPIPES and STORM WATER SYSTEMS -Overlappng cladding and roofing elements (e.g. WEATHERBOARDS and ROOF DIE) - Sloping window and doef SILLS and roof/wall FIASHINGS -Sloping the ground surface away from the walls at the base of buildings (to allow any water to run away from the building)
NEUTRALISING THE FORCES: The most secure strategies for keeping water out of buildings are those based on neutralising the forces which move water. The forces to be considered include: Gravity Surface tension and capillary action Momentum Air pressure differential
-Gravity strategies: Typically use slopes and overlaps to carry water away from the Building using the force of gravity.
-Surface tension and capillary action strategies: Use a drip and a break between surfaces to prevent water Clinging to the underside of surface (such as a window sill Or parapet capping).
-Momentum Windblown rain, moisture and snow can move through simple gaps. To inhibit this movement, the gaps are often constructed in more complex labyrinth shapes.
The complex shape slows the momentum of the moisture and helps to deflect the water away from the gap entry.
-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 equalisation chamber (PEC) is created and the water is no longer 'pumped' to the inside of the assembly.
DETAILING FOR HEAT: CONTROLLING HEAT: Heat GAIN and heat LOSS occur when: - Heat is CONDUCTED through the building envelope. -The building envelope and building elements are subjected to RADIANT HEAT sources. -THEMAL MASS is used to regulate the flow of heat through the building envelope.
Effective control of heat gain and heat loss saves energy, saves money and increases comfort levels for building occupants.
Conduction: can be controlled by using: -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 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. 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 envelope.
Thermal Mass: Large area 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
Controlling air leakage: -the principle of airtight detailing is similar to watertight detailing. If a building has: ď&#x201A;ˇ an opening ď&#x201A;ˇ air present at the opening ď&#x201A;ˇ a force to move air through the opening -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.
Knowledge MAP
Bibliography: Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘Detailing for heat and moisture’ https://www.youtube.com/watch?v=Lhwm8m5R_Co&feature=youtu.be Clare Newton, ‘Rubber’ https://www.youtube.com/watch?v=OPhjDijdf6I&feature=youtu.be Clare Newton, ‘Plastics’ https://www.youtube.com/watch?v=5pfnCtUOfy4&feature=youtu.be Clare Newton, ‘Paints’ https://www.youtube.com/watch?v=WrydR4LA5e0&feature=youtu.be
W08 STRAGETIES FOR OPENINGS KNOWLEDGE MAP
DOOR AND DOOR FRAME TERMINOLOGY
Deflection -is the perpendicular distance a spanning member deviates from a true course under transverse loading, increasing with load and span, and decreasing with an increase in the moment of inertia of the section or the modulus of elasticity of the material.
Shear force -Vertical -resist transverse shear, having a maximum value at the neutral axis and decreasing nonlinearly towards the outer faces. -Horizontal â&#x20AC;&#x201C;prevent slippage along horizontal planes of a beam under transverse loading, equal at any point to the vertical shearing stress at that point.
Moment of inertia -is the sum of the products of each element of an area and the square of its distance from a coplanar axis of rotation. -it is a geometry property that indicates how the cross-sectional area of a structural member is distributed and does not reflect the intrinsic physical properties of a material.
STRESS
1:1
Bibliography Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘Doors & Windows’ https://www.youtube.com/watch?v=g7QQIue58xY&feature=youtu.be Clare Newton, ‘Glass’ https://www.youtube.com/watch?v=_I0Jqcrfcyk&feature=youtu.be
W09 DETAILING STRATEGIES MOVEMENT JOINTS
CONSTRUCTION DETAILING
HEALTH AND SAFETY
AGEING GRACEFULLY
REPAIRABLE SURFACES AND RESISTANCE TO DAMAGE
CLEANABLE SURFACE
MAINTENANCE ACCESS
CONSTRACTABILITY
COMPOSITE MATERIALS-TWO OR MORE THAN TWO MATERIALS COMBINED (MONOLITHIC MATERIAL-A SINGLE MATERIAL)
FIBRE REINFORCED CEMENT (FRC)
FIBREGLASS
ALUMINIUM SHEET COMPOSITE
TIMBER COMPOSITE
FIBRE REINFORCED POLYMERS
STRESS & STRUCTURAL MEMBERS -External forces create internal stresses within structural elements. -Kern area is the central area of any horizontal section of a column or wall within which the resultant of all compressive loads must pass if only compressive stresses are to be present in the section. A compressive load applied beyond this area will cause tensile stresses to develop in the section. FINISH WORK-interior walls should be resistant to wear and be cleanable; floors should be durable, comfortable, and safe to walk on; ceilings should be relatively maintenance-free. -surface finishes have a critical influence on the aesthetic qualities of a space.
Knowledge map
Bibliography Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘Construction Detailing’ https://www.youtube.com/watch?v=yqVwAV7yJCI&feature=youtu.be Clare Newton, ‘Composite Materials’ https://www.youtube.com/watch?v=Uem1_fBpjVQ&feature=youtu.be
W10 WHEN THINGS GO WRONG STATUE OF LIBERTY: GALVANIC CORROSION THE PROBLEM Over time, the shellac-impregnated cloth become 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 built up of corrosion products (rust) expanded and pulled the rivets away from the copper skin. INITIAL CONNECTION DETAIL CONSIDERATION Galvanic corrosion between the copper skin and iron frame (DISSIMILAR METALS) was considered at the time 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. COPPER OXIDISATION When copper is exposed to the atmosphere, it reacts with oxygen. The copper starts to dull, first becoming a darker brown then forming a green copper oxide patina. THE SECOND SOLUTION: To overcome this problem, the original iron armature frame was replaced with o Tefloncoated 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.
DYNAMIC LOADS Two types: wind loads & earthquake loads
Wind loads are the force exerted by the kinetic energy of a moving mass of air, assumed to come from any horizontal direction. -the structure. Components, and cladding of a building must be designed to resist wind-induced sliding, uplift, or overturing.
-wind exerts positive pressure horizontally on the windward vertical surfaces of a building and normal to windward roof surfaces having a slope greater than 30째. -wind exerts negative pressure or suctions on the sides and leeward surfaces and normal to windward roof surfaces having a slope less than 30째.
Earthquake loads
-the natural period of a structure varies according to its height above the base and its dimension parrallel to the direction od the applied forces. Ralatively stiff structures oscillate rapidly and have short periods while more flexible structures oscillate more slowly and have longer periods.
-base shear is distributed to each horizontal diaphragm above the base of regular structures in proportion to the floor weight at each level and its distance from the base.
-any lateral load applied at a distance above grade generates an overturning moment at the base of a structure. -a restoring moment is provided by the dead load of a structure acting about the same point of rotation as the overturning movement.
Knowledge map
Bibliography Ching, Francis D.K., Building Construction Illustrated. Wiley & Sons, Inc., 2008
Clare Newton, ‘A tale of corrosion’ https://www.youtube.com/watch?v=2IqhvAeDjlg&feature=youtu.be