Construction AS Alchemy PDF

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CONSTRUCTION AS ALCHEMY LECTURE NOTES PASS: https://canvas.lms.unimelb.edu.au/courses/14068/pages/pass-sessions LECTURE 1 ● ● ● ●

Material principles Building systems Structural principles Detailing

Garden Wall House - Expansion joints in concrete and brick walls to stop cracking when parts get hot Ruckers Hill house Structural Systems - Solid systems: have structure to them Compression action, arches - Shell/Surface systems: Oprah House - Frame/Skeletal systems: Very efficient in transferring loads (eiffel tower) - Membrane systems: efficient in tension - Hybrid systems: Structural frame with others, e.g. The eden Project, ETFE membrane hybrid Materials - Strength: Steel is stronger in compression and tension than timber - Stiffness: Characteristic, flexibility, floppy, stretchy - Shape: Mono-dimensional (linear), bi-dimensional (planar), tridimensional (volumetric) - Material Behaviours: Isotropic or anisotropic? - Issues around economy; Expensive, readily available? Impact on environment, ease of transport, efficient? - Sustainability Construction systems - Performance Requirements: age gracefully, easy maintenance, easily repainted or replaced - Aesthetic qualities: proportion, colour, surface qualities, - Economic efficiencies: affordability, initial cost and life cycle costing (longevity and performance)

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Regulatory constraints: hospitals and kitchens needs materials that dont harbour bacteria easily Environmental impacts: embodies energies, material efficiency, lighting, air conditioning Structural compatibility

Studio 1 - Wall Assignment - Site plan (1:100), Plan, Elevation (external finishings), Section (cut elevations) - TIM (timber - AL (aluminium - Diamond shape - external finish - Circle shape - doors and windows - BLK - blockwork - Hexagon - J WEEK 2 9.81m/s2 = gravity Key points: material strength, durability, tension and compression, structure Dead loads - Static - Permanent - Weight of materials Openings ● To hold an opening open, we use a lintel ● Assignment 1 - Steel lintel either flat or angled ● Hold the weight above the opening so the opening doesnt start to sag ● E.g. biblioteca Tiraboschi, Italy by Mario Botta 2004 - massive structural device holding the building up ● Chau Chak Wing building UTS, Sydney Australia Live loads - Temporary - Dynamic - Things that can move, or can be moved (occupants, furniture) - Consideration for very heavy things - Adding things to space Scale - Do all plans and elevations at the same scale

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Label Put a scale Squiggly lines - insulation Clip lock roof

E LEARNING 2 Site Observations and Drawings - Dark black BOLD outlining highlight existing building and or site dimensions - Lines must connect always - Hatching must be associated with a key - Survey points - Datum - Cardinal Directions - Dash lines in circle indicates demolished tree, solid circle shows trees still standing - New trees have a plus in circles, old have an ‘o’ - Dotted line is council line, shows where you can and can’t build on Footings and foundations - Buildings need to be stable and not move - Bits below the ground hold down the building as foundations - Foundations - substructure of the bilding and their function is to safely transfer all loads acting on the building structure to the ground - Foundations support the superstructure - Loads need to be transferred into the footing of the building, if loads are too heavy the building will sink into the ground and cease to be static. - Dead (static loads permanently attached to building) and live loads (moving loads, wind earthquakes, people, furniture) - Design must respond to shape weight material of superstructure - Shallow footing (used when soil conditions are stable) and deep foundations (used when soil conditions are unstable) systems - Geotechnical engineers that test the conditions Types of Shallow footings ● Pad footings/Isolated footings - spread a point load over a wider area of ground ● Strip footings - used when loads from a wall or series of columns is spread in a linear manner ● Raft foundation/Raft slab - provides increased stability by joining the individual strips together as a single mat

Retaining and foundation walls - used when sites are excavated to create basements or where changes in site levels need to be stabilised. Pressure load of earth behind the wall needs to be considered to prevent the wall from overturning. Types of Deep foundations ● End bearing piles - extend the foundations down to rock or soil that will provide support for the building loads ● Friction piles - rely on the resistance of the surrounding earth to support the structure To construct these driving lon timber, steel or concrete members can be used Drill holes in ground then fill with concrete (metal cages will be installed already) Mass Materials -

Stone: Temples, Walls , pryamids Earth: earth walls Clay: bricks, shaped and cut, roman architecture Concrete: more recent 1900-

Very strong in compression, weak in tension Hard and resist abrasion Good thermal mass and tend to be durable ●

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Modular - Clay brick - Mud brick (adobe) - Concrete block - Ashlar stone Non Modular - Concrete - Rammed Earth - Monolithic stone (columns and beams)

Masonry Bond the pattern or arrangement of the units Course a horizontal row of masonry units Joint the way units are connected to each other Mortar mixture of cement or lime, sand and water used as a bonding agent Masonry is a particular subset of mass construction made from smaller units of various natural or manufactured materials, usually within the use of mortar as a bonding agent (Ching 12.06) Can be made from:

Stone - Slabs, Ashlar blocks, rubble stone, beams, lintels, arches - Vaults and domes Earth - Mud bricks Clay - Bricks, honeycomb blocks Concrete - Blocks, commons Stone -

Sedimentary: formed when accumulated particles are subjected to moderate pressure (limestone, sandstone), prone to damage by water and stone, easily carved and shaped Igneous: formed when molten rock cools (granite, basalt, bluestone), impervious to water Metamorphic: formed when sedimentary or igneous is subjected to pressure or high temperatures and chemical processes (marble, slate) Monolithic - large individual stones forming beams and columns Ashlar - when stones are carved into smaller modular units, flat faces Rubble: stones used as they are found

Properties: - Hardness - Fragility - Ductility - Flexibility/Plasticity - Porosity - Density - Conductivity - Durability/Lifespan - Sustainability - Cost - Reusability/Recyclability Brick Standard size 230 x 76 x 110 Clay bricks - Manufactured from clay or shale - Can be 1. Extruded and wire cute 2. Machine moulded ( pressed )

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3. Handmade (convict made) Variation in brick colours as clay is natural, depends on amount of iron (more pink), grey and brown with magnesium Porous (draws in moisture) Stretcher course, header, brick on edge, soldier Mortar joints are 10mm Vertical joints are called perpends, horizontal called bed joints Efflorescence: When moisture that has been absorbed, and start to evaporate and leave a sandy texture on unfinished brick Finishings 1. Raked 2. Ironed 3. Weather struck 4. flush

Properties: - Hardness: medium/high, can be scratched with metal - Fragility: medium, can be broken with trowel - Ductility: very low ductility - Flexibility/Plasticity: low - Porosity: medium-low - Density: medium - Conductivity: poor - Durability/Lifespan: very - Sustainability: local, firing process adds to carbon footprint - Cost: locally produced but labor costs - Reusability/Recyclability: can be reused Adv ● Can be joined with water based mortar ● If ventilated well, wetness can escape and they won't deteriorate Disadv ● Absorbs some moisture and expand overtime, expansion joints required every 10m ● Salts and lime from soil can be drawn up through the bricks when in contact with the ground. This may cause serious pathologies and or aesthetic problems as efflorescence Concrete blocks -

Two handed Typically have holes in them to reduce weight and increase insulation and helps make it easier to carry Manufactured from cement, sand, gravel and water. Process involves mixing moulding, and curing.

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Can be hollow or solid Carry particular tensile loads

Properties: - Hardness: medium/high, can be scratched with metal - Fragility: medium, can be broken with trowel - Ductility: very low ductility - Flexibility/Plasticity: low - Porosity: medium, they are sealed to stop absorption - Density: medium - Conductivity: poor - Durability/Lifespan: very - Sustainability: reusing allows increase in sustainability. Positive reduction in carbon footprint - Reusability/Recyclability: medium - can be crushed to be use as rock aggregate in other concrete processes - Cost - generally cost effective but labour penalties come in Bespoke designs Key points - Clay bricks expand overtime, whereas concrete shrinks - Cement paste reduces in volume as it hydrates and drying shrinkage occurs as water gets lost to atmosphere - Clay bricks absorb moisture from atmosphere and therefore expand - Movement joints required for each material. Steel is good in compression and tension Brick, stone, masonry, concrete are good at resisting compression loads Bridges are good in tension loads Timber is anisotropic Steel, glass is isotropic FMS - flat m steel, larger the section the more loads it can transfer LECTURE 3 Beams 1. Cantilever 2. Simply supported 3. Overhanging 4. Fixed 5. continuous

Trusses 1. Eames House (1949) has a series of trusses that give stability to the building Structural systems depend on: - Function - Materials - Location - Local weather - Height - Design intent (aesthetic) - Budget - Expertise of design team - Expertise of the construction team Cantilevers - Canada white tower: tallest inclined structure in the world - Grand canyon cantilever - Museum between austria and italy - Beijing CMG tower Exoskelton E LEARNING 3 -

Structural elements 1. Strut - compression element E.e. columns 2. Tie - tension element E.g. in bridges 3. Beam - supports a load, top part tension, two sides compression E.g. bridge 4. Slab/plate 5. Panels, walls can carry and transfer loads, also act as bracing systems 6. Shear diaphragm - or a bracing system that consists of struts and ties

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Concrete 1. Components: 1 part cement, 1 part fine aggregate, 4 part coarse aggregate, 0.4-0.5 part water 2. Too little water - stiff, too much water - too weak 3. When cement powder and water are mixed, chemicxal reaction takes place and heat is released - hydrations 4. Adv - plastic fluid before it forms, it is flexible and can be used in formwork

5. Formwork can be built on site or precast 6. Wall formwork -- spreaders, ties, timber studs, steel plate, bracing 7. Bracings and props are used during curing processes - concrete is heavy while setting 8. Concrete reaches 75% of its compressive strength in 7 days Reinforcement - Mesh and bars used to reinforce concrete using materials strong in tension (steel)

PROPERTIES - Hard - Low fragility - Low ductility - Low flexibility and plasticity -

Medium porosity Meium- high density Very durable Hard to recycle but element can be recrushed Cost effective

Concrete is permeable, main problem - Steel bars too close to surface will be unprotected from moisture and oxidation Concrete may be set with poor vibration - Air bubbles may not all be dealt with, lessening structural performance In Situ Concrete - Concrete cast in place an cured on site - Takes shape of which it is laid - Requires assembly of formwork and reinforcement, the pouring, vibration and curing of the concrete. - Use floats to get a flat finish (by hand) - Limited time before concrete sets - Usefu in footings, retaining walls and all bespoke structural element -

Can also be prayed using a pressure house (shotcrete), good for landscape architecture Construction joint - when we need to divide the construction in smaller and more manageable sections Control joint - required to absord the expansion and contraction that thermal variations cause and the long term tendency for concrete to shrink. Elongation/

shrinkage is proportional to the temperature differentialm the material coefficient and dimensions of space Both joints are potential weak points and must be detailed appropriately, especially in terms of water and moisture control. PreCast concrete - Paels being craned, precast panels - Precast: fabricated in a controlled factory environment and then transported to site - More standardised outcome, avoids quality control issues - Allow faster construction progress Uses -

Needs to be supported in place until remaining structure is put in Rarely used in footingsm but used in columns, retaining systems, walls

Precast joint - Construction joint: the panel/elemental nature of precast concrete means that joints naturally occur when one precast element meets another - Structural joint: the type and performance of hte structural connections joining the precast elements to each other and to other parts of the structure are critical for the overall performance of the building Joints depend on desired outcome - Patch plate can be hidden or shown Finishes can be done more detailed Precast - limited in size, and onsite changes are hard to incorporate Benefits in repetitions E LEARNING 4 1. Structural forces Force - any influence that produces a change in the shape or movement of a body. - Vector quantity (magnitude and direction) - Arrow representation is proportional to the magnitude of the force and orientation shows the direction - Linear forces → straight line - Vector sum - algebraic sum of magnitudes of the forces -

Compression forces 1. Produces opposite effect of a tension force 2. Compression forces result in the shortening of the material.

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Tension forces 1. When an external load pulls on a structural member, particles composing the material spread apart and undergo tension 2. Tension forces stretch and elongate the material 3. Amount of elongation depends on material stiffness, cross sectional area, and the magnitude of the load

Structural Joints 1. ROller Joints - Vertical load in just one direction 2. Pin joint - Modes of actions can be in more than one direction 3. Fixed joints - If load occurs at one point, it can cause a bending at a joint - Transfers moment Beams and Cantilevers -

Beam: a mostly horizontal structural element 1. Function - to carry loads along the length of the beam and transfer these loads to the vertical supports. 2. Can be supported at both end of the beam 3. Supported at numerous points along the length of the beam 4. Supported at points away from the ends of the beam (creates overhangs/cantilevers beyond the supports) 5. Supported at only one end of the beam (these beams are called cantilevers)

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Cantilever: created when a structural element is supported at only one end (or the overhanging portions of a member are significant) 1. Function - to carry loads along the length of a member and transfer these loads to the support 2. Can be horizontal, vertical or angled.

Load paths Load path - represent loads as arrows with direction and scale, load paths travel down the support structures (e.g. bricks, cranes) At the ground, applied loads have a reaction to mean the structure is stable. Action and reaction forces are equal. (equilibrium)

Span and spacing - Span: distance measured between two structural supports 1. Can be measured between two vertical supports (for a horizontal member) or between two horizontal supports (for a vertical member) 2. Span is not necessarily the same as length of a member -

Spacing: the repeating distance between a series of like or similar elements 1. Often associated with supporting elements (like beams and columns) 2. Can be measured horizontally or vertically 3. Generally measured centre line to centre line

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

Geometry and Equilibrium Centre of mass - The point about which an object is balanced 1. AKA the point where the entire weight of the object is concentrated 2. Location of COM is dependant on the objects geometry 3. Also sometimes referred to as the centre of gravity Equilibrium - state of balance or rest resulting from the equal action of opposing forces. 1. AKA as each structural element is loaded its supporting elements must react with equal but opposite forces 2. For an object to be in equilibrium, any applied forces must be resisted by equal and opposite forces. These forces are called reaction forces 3. In building structures, the reaction forces are developed in the supporting elements. Free body diagrams - Real life appearance of elements is replaced by simple lines with symbols showing the types of structural connections used (roller, pin and fixed joint) - Applied forces (F) and reaction forces ® are represented by arrows Equilibrium = object / system at rest - If object or system isnt moving up or down, v=0 - If object or system isnt moving side to side, h=o - If object isnt rotation, sum of moments is M=0 Moment of forces Moment - the tendency to make an object or a point rotate

A force will only produce a moment about a point if it is applied at a distance from that point along a line of action that does not pass through a point Moments are measured by the product of the force magnitude and the perpendicular distance between the line of action (moment arm) Mo=Fxd unit Nm or kNm (clockwise = -ve moment, anti clockwise = +ve moment Deck Design fundamentals Frame system ● ● ● ●

36sqm single level deck 1:20 @ a3 600mm high platform At least 150mm clear underneath to stop timber decay - timber needs ventilation, so it doesnt mold, rot and decay

Beams, cantilevering Cantilever - no more than 200mm Continuous beam system ______________ ^ ^ ^ Think about how material ill start to behave with live loads Stress grades - F14 1. 2. 3. 4.

Footings - hold our structure to the ground Bearers - attach to the footings Joists Decking boards across the top

Structural stability across a range of elements so system doesn't wobble 4.5kN (light pedestrian traffic)- point load - 1kN = 1000N - Gravity on earth = 9.81 m/s^2 Deicking board size: 35x120 Allowable decking span is 450

Unseasoned timber Continuous span Maximum riser height of 190 Minimum tread of 240

E LEARNING 5 Stress and structural members -

When structural members resist loads = the materials of these members experience stress Depending on member type and type of load applied, different types of INTERNAL STRESSES are created For most applications the most essential requirement is that maximum stresses do not exceed allowable strength of the material.

Stresses that should be considered when determining how members will behave: 1. Tensile and compressive forces 2. Shear stress 3. Bending stress 4. Torsional stress TENSILE AND COMPRESSIVE FORCES AXIAL STRESSES ● Occur when structural members experience a pulling force (tensile) or pushing force (compressive) along the length of the member. - STRUT ELEMENTS Short columns, compression members in trusses and horizontal spacing members. 1. Compressive stress results in shortening - TIE ELEMENTS Tie rods, tension members in trusses, tie beams and cables 1. Tensile stress results in the lengthening of the member Tensile and compressive stress are measured as a factor of the load applied and the cross sectional area of the member (i.e. the area perpendicular to the length of the member). Stress (MPa) = Load (N) / area (mm^2)

SHEAR STRESS ● Occurs when structural members experience opposing forces close together - these cause the particles of material in the member to slide against each other - STRUT ELEMENT...