WEEK 3 â€“ footings and foundations Structural elements: Strut: a slender element design to carry load parallel to its long axis. -- The load produces compression. Tie: a slender element design to carry load parallel to its long axis. --The load produces tension. Beam: a horizontal element designed to carry vertical load using its bending resistance. -- The combination of compression and tension forces. -- Normally, use reinforced concrete, steel and timber( not easy to break) Slab/plate: a wide horizontal element designed to carry vertical load in bending, usually supported by beams. --The load across the slab will be distributed to the beams. Panel: a deep vertical element designed to carry vertical or horizontal load. Type of timber: Hardwood (gum): use for window desk framing joinery Softwood (pine): useful for timber frame Plantation pine or plantation softwood
Footing and Foundations: What is the difference between footings and foundations? The footing lies on the ground around the base of the structure. The foundation can go below with pilings deep into the ground. Footing is the part of foundation, which transfers the load directly to the ground. Foundations (substructure) are found at the bottom of buildings where the building meets the ground. 1. Shallow Foundation: Shallow or spread foundations are employed when stable soil of adequate bearing capacity occurs relatively near to the ground surface. (Ching, 2008) 2. Deep Foundation: Deep foundations are employed when the soil underlying a foundation is unstable or of inadequate bearing capacity. (Ching, 2008) Considerations of selecting and designing (Ching,2008): Pattern and magnitude of building loads Subsurface and groundwater conditions Topography of the site Impact on adjacent properties Building code requirements Construction method and risk
footing: Under each point of support.
Strip footing: Strip footings are the continuous spread footings of foundation walls.
Mat footing A mat or raft foundation is a thick, heavily reinforced concrete slab that serves as a single monolithic footing for a number of columns or an entire building.
Retaining Wall+Foundation Wall: are used when sites are excavated to create basements or where changes in site levels need to be stabilized. Settlement: over time, buildings compress the earth beneath them and the building tend to sink a little into the earth (bearing capacity).
Free body diagrams: Objects or systems in equilibrium can be represented in diagrammatic form. These materials are the group, which are strong in compression, but weak in tension.
Masonry materials: STONE - Slabs - Ashlar block - Rubble stone
EARTH - Mud bricks (Adobe)
CLAY - Bricks (hard) - Honeycomb blocks
CONCRETE - Blocks
Masonry Definitions: Masonry refers to building with units of various natural or manufactured productsâ€Śusually with the use of mortar as a bonding agent (Ching, 2008). 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 properties: The units together act as a monolithic whole.
Geometry and equilibrium CENTRE OF MASS: The centre of mass is the point about which an object is balanced. EQUILIBRIUM: Equilibrium is a state of balance or rest resulting from the equal action of opposing forces (reaction forces: applied forces must be resisted by equal and opposite forces.) Moments: are measured by the product of the force magnitude and the perpendicular distance between the line of the action of the force and the point (this distance is called the moment arm).
Mo = F x d (i.e. moment = force x distance) Mo (Nm/kNm) Clay Bricks: Main types of Mass materials that use in mass construction: bricks: Early bricks
(handmade)machine molded (pressed)extruded and wire-cut. Clay is a natural material so there is a wide variation in the color of bricks.
Brick can be arranged in various ways to create different bond pattens
Mortar joints (usually is 10 mm): vertical joints: perpends horizontal joints: bed joints Bricks properties: Hardness- medium-high - can be scratched with a metallic object Fragility- medium - can be broken with trowel Ductility- very low ductility Flexibility/Plasticity- very low Porosity/Permeability- medium - becomes soaked only if placed in prolonged contact with water Density- medium (2~2.5 more dense than water) Conductivity- poor conduct of heat and electricity Durability/Life span- typically very durable Reusability/Recyclability - high - can be reused with no change or crushed to be used as recycled aggregate Sustainability and carbon footprint - tend to be locally produced - the firing process (1200 degrees)adds to its carbon footprint Cost- effective but required labour costs should also be considered Bricks are permeable: Advantages: they can be joined with water based mortar If adequately ventilated so that any wetness can escape Disadvantages: -the absorb moisture and expand overtime (expansion joints required)
-Salts and time from the soil can be drawn up through the bricks when contect with the ground (efflorescence!)
Concrete blocks: Concrete blocks are manufactured (mixing, molding and curing)form cement, sand, gravel and water. 4Why do concrete blocks have holes in the middle? Allows reinforcement roads to be installed within the blocks. Uses: used in construction of walls both load bearing and non-load bearing Properties: hardness- medium-high - can be scratched with a metallic object Fragility- medium - can be broken with trowel Ductility- very low Flexibility/Plasticity- very low Porosity/Permeability- medium. - some concrete blocks are sealed to reduce the opportunity for water absorption. Density- medium (2~2.5 more dense than water) Conductivity- poor conduct of heat and electricity Durability/Life span- typically very durable Reusability/Recyclability- medium. Sustainability- inclusion of recycled and waste products from other processes is allowing a positive reduction in carbon footprint and increase in sustainability for many concrete products Cost- effective but labour penalties are often applied as the lager format units Mean construction progresses at a faster rate.
Stone: Igneous stone (granite, basalt and bluestone): is formed when molten rock cools. Sedimentary stone (limestone and sandstone): is formed when accumulated particles are subjected to moderate pressure. (can be carved easily and shaped, because of the softness) Metamorphic stone (marble and slate): is formed when the structure of igneous or sedimentary stone changes when subjected to pressure, high temperatures or chemical processes Properties: Hardness- igneous is hardest, then metamorphic and the sedimentary Fragility- largely geometry dependent Ductility- most stones have very low ductility Flexibility- most stones are rigid Porosity- large range Density- largely depending on stone type Conductivity- poor conduct of heat and electricity Durability- typically extremely durability
Reusability- very high Sustainability- transport energy is the main factor - stone sourcing has a high environmental cost Cost- largely depending on labour
3 ways to make a frame structure stable: 1. Triangulation 2. Joint 3. Shear panels
Class task: Descriptions: to introduce the concept of built scale and to identity the basic structural systems, construction systems and materials of the Pavilion Case Study building and a variety of other buildings on campus.
Steel frame - Concrete on precast concrete - bricks as the base.
Lot 6 CafĂŠ Steel structure And the SPAN (UB) across the open area.
Floor system Old Quad (1854) Underground carpark -The old quad is the oldest part of the TheUniversity reason why the ceiling is designed in this particular -Built in the Tudor Gothic style shape is because there are trees on the top of the parking lot. This kind of shape leaves trees enough space to grow.
Pilaster: to give the appearance of a supporting column and to articulate an extent of wall, with only an ornamental function. In contrast, an engaged column or buttress can support the structure of a wall and roof above.
Art (west) building: Long span. Steel structure + triangulation
-The Beaurepaire Centre at the University of Melbourne was constructed in 1956 -The building has always been an important element in the sporting activities. -Curtain walls Stairs on west end of Union House: -brick frame -Steel frame
Materials: steel(joints to timber(joints to Slabs system: span between
-UB holding up the stairs -The wire rope produces the tension load
North Court Union House This is typical architecture that use tension loads to create certain shape.
concrete , joints) and joints) -used to structural
-One way/two way span Steel system: Steel framing system- in various forms - utilising heavy gauge structural steel and other using light gauge steel framing Sometimes combine with slab system.
Timber system- combination of bearers and joints Bearer- primary beam Joist- secondary beam
Concrete: Common concrete mix 1. Cement - portland, lime 2. Fine aggregates- sand 3. Coarse aggregates - crushed rock 4. Water PS: Too much water added - final concrete will not be strong enough Little water added- concrete mixture will be too stiff and not workable enough
WEEK 4 â€“ Floor systems and horizontal elements Span and spacing SPAN: -the distance measured between two structural supports. -Can be measured between vertical supports (for a horizontal member) or between horizontal supports (for a vertical member). SPACING: - is the repeating distance between a series of like or similar elements. - Is often associated with supporting elements (such as beams, columns etc.) and can be measured horizontally or vertically Spacing of the supporting elements depends on the spanning capabilities of the supported elements Thoughts: The site in the drawing does not make sense to me at first. I could not imaging what the actual building looks like. Then I wen to the site and compared the drawing to the building. Finally, I got an clear idea of what does my site look like. To identify each part of the s I think thetasks: bifference between architectural drawing and structual drawing is scale. Class structure (shown in the Architectural drawing do not need to do in scale and it is not standarized picture ). Descriptions: Structural drawing has to be spcefic, especially some structural details and use of material. Understanding the concept of scale and how it applies to construction documentation. -Joist spacing -Joist -Foundation wall -Cantilever
In situ concrete: In situ concrete is any concrete element that has been poured into form work and cured (hydration chemical processes) on the site. - the fabrication and assembly of the form work, - placing any required reinforcement, Formwork: - the pouring( concrete has beenitpoured, there is a limited time Advantages of concrete: fluidonce and shapeless before hardens. before support its starts to harden and become unworkable) , Formwork: -temporary -vibration( air bubbles removed) and in theplace curing of the concrete. -Moulds used to hold liquid concrete Use- structural footing -Can be purposesbuilt in situ or in factory - retaining walls Reinforcement Concrete: - all bespoke structural elements Because concrete: strong in compression, weak in tension landscapes, swimming pools and basement walls between piers or overhead surfaces ( the concrete is sprayed into Steel reinforcement in the form of using mesh aorpressure bars is added reinforcement concrete place hose( --shotcrete) (Properties in WK3) Joints in in situ concrete To improve
Construction used to divide the construction into smaller and more Beams andjoints: Cantilevers: manageable sections of work Beams: are (mostly) horizontal structural element. Control joints: absorb and contractions that thermal - Carry loads alongthe theexpansions length of the beam variations cause the long term tendency of concrete to and transfer these loads to theand vertical supports. Shrink over time. Beam can be: -proportional the temperature differential, the material - supported at both ends of thetobeam coefficient andalong the dimensions of beam the piece. - supported at numerous points the length of Potential weak points:away control andofconstruction - supported at points fromjoints the ends the beam joints Need to ensure detailed appropriately (water and moisture (creating overhangs / cantilevers beyond the supports) - supported at only onecontrol) end of the beam (these beams are called cantilevers)
Precast concrete: Cantilevers: Precast concrete Is any concrete element that has been fabricated a controlled Cantilevers are created when a structural element is supported atinonly one end (or the environment then transport to site overhangingand portions of a member are significant). Processensure much along more standardized outcome. Cantilevers: carrya loads the length of the member and transfer these loads to faster rate the-much support. Usesstructure bridge or civil works Cantilever can of be:a -building, horizontal - forming part of the primary structure/ self-supporting panel - vertical - footings, retaining walls, walls and columns - angled Some common symbols that we use in a Joints standard drawing Construction joints- joints naturally occur when one precast element meets another.
It helps us to understand each element in Structural joints- structural connections joining the precast the section plan elements to each other and to other parts of the structure are critical for the over all performance of the building. Both depend on the desired aesthetic outcome. Steel: - hot rolled steel (primary structural)