Constructing Environments Logbook Journal Godwin Low
Tutorial #01 of Constructing Environments: Introduction to Construction Definition of key terms learnt this week: Masonry – stonework
Load path – The arc traced by a turn oflogs along a skyline and generally plotted graphically to determine ground clearace. Compression – ‘Pulling’
Point load - A load which is localised to a specific location on a structure
Beam – A long, sturdy, piece of squared timber or metal used to support the roof or floor of a building Structural Concepts: Loads and forces
Construction systems: Construction Overview Materials: Introduction to materials Talks of 3 kinds of forces that happens to buildings was brought in by tutor Wil. It involves: -pushing (tension)
-pulling (compression) -twisting (torsion)
These forces can be largely affected by two other kinds of forces, them being:
-Materials chosen
- Structure system
Forces are defined by direction, sense and magnitude
Compression, tension and torsion are all characteristics of mass construction. Accompanying images also show of diagrams such as how a window is shown on an architectural plan, how certain tiny details are added to buildings to allow for better sustainability, etc.
Introduction to material When selecting materials, there are always few perspectives to consider if the material chosen is appropriate. They are: Strength – Strong in tension/compression, weak in tension/compression Stiffness – Stiff, flexible, stretch, floppy? Shape – Mono-dimensional (linear), bi-dimensional (planar) or tridimensional (volumetric) Material behaviours – isotropic or anisotropic? Economy & sustainability – How expensive? How readily available? What impact does it have on the environment? Does it have to be transported? How frequent does it get used in the construction environment?
Load paths
Red bolded Arrow – Applied Load Yellow Arrows – Load path Red border arrows – reaction forces
ACTIVITY of the week: Tower building Objective: To have a tower built as high as possible with the least amount of blocks used, and an entrance fitting the size of a plastic model of a dinosaur was to be included in said tower Plan: (In image) My group came up with an idea that the tower built should be of a cylinder like shape instead of square/rectangle as it uses the least amount of bricks and at the same time has quite a high stability. The blocks were placed in mind with them having spacing in between to minimize the amount of blocks used and consequently have a simple but efficient design for the look of the tower. Action: There was no change of plan as the idea that my group came up with seems to be efficient and simple enough to carry out. i)
ii)
iii) iv)
Our group first started with the outline of half a circle and as we measured the size of the dinosaur, the doorway was first built to ensure that the model of the dinosaur was able to enter. Our group then proceeded to build up the walls of the tower, the more time passed, the higher the tower was built At the point where the gate was being covered, our group decided to change the position of the blocks. Instead of having it lie down to ensure stability, we had the block standing vertically to focus better on its height. However as the lesson came to an end, the group was told to get rid of any unnecessary blocks, the tutor Wil reached into the base of the tower and pulled out a handful of blocks, surprisingly the tower remained standing.
(Pictures are placed according to number, in a clockwise fashion starting from the top left.)
Sources of pics: Jil Eng
The lesson ended with Wil teaching us about how a door is built in real time and how the weight on the top, and all the other blocks are preventing the tower from falling down. At the end of class, we were given a piece of plywood to cut up in preparation for next weeks classes.
Tutorial #02 of Constructing Environments : Structural loads and forces Structural Concepts: Structural systems and connections Construction Systems: Construction Overview Materials: ESD and Materials Class today focused on load paths and reaction forces, showing how a reaction force and load path interacts. If a weight is not distributed equally on a beam, more of the weight of the objects move closer to the closest support. A reaction force will always go the opposite direction of the load path. As long as a structure is standing, there will always be equal opposite reaction to keep the building standing. Definitions of key terms learnt this week: ESD – Environmentally Sustainable Design
Thermal Mass - Ability for stuff to store heat
Night air purging – When you have built up heat problem and method is used to keep buildings cool by flushing out the hot air, storing cool air at night Frontal Ventilation – Used to control temperature in buildings Services system – water, electric, air, movement Dead load – Consistent Load
Live load – Inconsistent Load
Bracing – Serving to brace a structure, reinforcing it
Structural Joint - A joining of two pieces of material in wood, metal or plastic by mechanical Frame – A rigid structure that surrounds something
Column – An upright pillar, typically cylindrical, supporting an arch, entablature or other structures or standing alone as a monument
Stability – The state of being stable; a level indicated of an objects ability to be able to collapse due to forces out of its control
Structural Systems Solid systems – Structures we might find in ancient buildings (compression is main structure in the system) Shell/surface systems
Frame/skeletal systems – Efficient way of transferring loads to the ground Membrane – Used less commonly in built environment
Hybrid systems – Where there is a structural frame cladded with something Construction systems
Building Construction Illustrated Structural System The structural system of a building is designed and constructed to support and transmit applied gravity and lateral loads safely to the ground without exceeding the allowable stresses in its members -Superstructure is the vertical extension of a building above the foundation -Columns, beams, load bearing walls support floor and roof structures
-The substructure is the underlying structure forming the founcation of a building Enclosure system
The shell or envelope of a building, consisting of root, exterior walls, windows and doors
-Roof and exterior walls shelter interior spaces from inclement weather and control moisture, heat, and air flow through the layering of construction assemblies
-Exterior walls and roofs also dampen noise and provide security and privacy for the occupants of a building -Doors provide physical access
-Windows provide access to light, air and views
-Interior walls and partitions subdivide the interior of a building into spatial units Mechanical systems
-Water supply system provides portable water for human consumption and sanitation
-Sewage disposal system removes fluid waste and organic matter from a building
-Heating, ventilating, and air-conditioning systems condition the interior spaces of a building for the environmental comfort of the occupants -The electrical system controls, meters, and protects the electric power supply to a building, and distributes it in a safe manner for power, lighting, security and communication systems
-Vertical transportation systems carry people and goods from one level to another in medium – and high – rise buildings
-Fire fighting systems detect and extinguish fires
-Structures may also require waste disposal and recycling systems
Performance requirements
-Structural compatibility, integration and safety
-Fire resistance, prevention, and safety
-Allowable or desirable thickness of construction assemblies -Control of heat and air flow through building assemblies
-Control of migration and condensation of water vapor
-Accommodation of building movement due to settlement, structural deflection, and expansion or contraction with changes in temperature and humidity -Noise reduction, sound isolation, and acoustical privacy -Resistance to wear, corrosion and weathering
-Finish, cleanliness, ad maintenance requirements -Safety in use
Aesthetic qualities -Desired relationship of building to its site, adjacent properties and neighbourhood -Preferred qualities of form, massing, colour, pattern, texture and detail Regulatory Constraints
-Compliance with zoning ordinances with building codes Economic Considerations
-Initial cost comprising material, transportation, equipment, and labor costs
-Life-cycle costs, which include not only initial cost, but also maintenance and operating costs, energy consumption, useful lifetime, demolition and replacement costs, and interest on invested money Environmental Impact
-Conservation of energy and resources through siting and building design -Energy efficiency of mechanical systems
-Use of resource – efficient and nontoxic materials Construction Practices Safety requirements
Allowable tolerances and appropriate fit
Conformance to industry standards and assurance Division of work between shop and field
Division of labor and coordination of building trades
Budget constraints
Construction equipment required Erection time required
Provisions for inclement weather ESD and selecting Materials
ESD considerations : Embodied energy is the total energy (oil, water, power) used during oil stages of a material’s life.
Life Cycle begins with the extraction of raw materials from the Earth and ends with the disposal of waste products back to the earth or recycled (partially or totally) into other products Stages Raw Material Acquisition >> Primary Processing and Refining >> Manufacturing >> Delivery >> Construction Use and Maintenance >> Final Disposal
Recyclability is potential for a product/material to be re-used or transformed into new product Carbon Footprint is a measure of the amount of greenhouse gases generated during the fabrication, transportation and use of a particular product. Common ESD STRATEGIES: -Local Materials
-Material Efficiency -Thermal Mass -Night Air Purging -Solar Energy -Wind Energy -Cross Ventilation -Smart Sun Design -Insulation -Water Harvesting Structural Joints 3 main joints to consider
Roller Joints have loads transferred only in one direction, but if there are additional loads being pushed in any other direction, the roller just moves Pin Joints useful in making assumption on how structural system might behave, it works most in a truss
Fixed Joints are most complex joints to calculate as if there’s a load in one member it could cause bending in the joint
ACTIVITY: FRAME
The wood received from last week was told to be cut into slices as thin as possible, and after we were told to construct a building that is as high as possible, but at the same time has to be stable. Unfortunately our class didn’t have enough time to complete the activity due to lack of time. The only time we had for was for ideas. My group came up with the idea that a structure similar to the paris tower should be built as it’s a solid structure with little faults. The closest we got to was building the base of the tower, as we had to wait for the glue to set. The pieces of wood were cut too thinly, and as they were very brittle, it was extremely hard to glue them together in the first place. The following is a picture the closest our group got to by the end of the lesson.
EDIT: The wood skewers were missing in the following we ek, hence the work could not be done. Unfortunately photos were missing too
Tutorial #03 of constructing environments Structural Concepts : Structural Elements/ Geometry & Equilibrium Construction systems : Footings and foundations Materials : Mass and Masonry Materials Todays class focused highly on the walls being built and the geometry that is needed for the building to stay erect and not succumb to the tension it is facing. Extra materials such as having a core filled block wall to prevent it from falling down, hollowed block work so that steel pipes can be fitted in. Force x distance = Moment
Reaction = Opposite of force
Some concrete blocks have holes in the middle because it allows for reinforcement rods to be installed within the blocks Definition of key terms learnt this week Strut – When something is in compression, holding something up (eg steel column, timber beam, etc) Slab on ground – when a foundation slab is laid on the ground without basement Substructure – An underlying or supporting structure Retaining Wall – A wall that holds back earth or water Pad footing – A thick slab-type foundation used to support a structure or a piece of equipment Moment – Relates to the perpendicular distance from a point to a line or a surface Strip foundations – Foundation – A foundation is a base, the area of the building that’s holding it up Perpend – The horizontal area between the bricks where the cement lays Expansion point – The area where foam/rubber (usually) is slipped in between walls to allow for materials to move (due to tension/compression) Ironed mortar joint – The different pattern at the ending of the cement Header face – Elevation of head of brick Stretcher face – Colour/shape of brick Mortar – Made from a mix of hot sand and water 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, The elements from which a structure is mode or assembled have, in engineering or building terms, specific names which are used for convenience
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 : Generally a horizontal element designed to carry vertical load using its bending resistance Slab/plate : A wide horizontal element designed to carry vertical load in bending usually supported by beams Panel : A deep vertical element designed to carry vertical or horizontal load
Footings and foundations Foundations are found at the bottom of buildings where the building meets the ground. The foundations are substructure of the building and their function is to safely transfer all loads acting on the building structure to the ground. Where parts of the substructure are located below the ground, the foundations must also resist the force of the soil pressing against the foundation (or retaining) walls.
Foundations and settlement Settlement : Over time, buildings compress the earth beneath them and the buildings tend to sink a little into the earth Footings and foundations should be designed to ensure that this settlement occurs evenly and that the bearing capacity of the soil is not exceeded
Cracking in a building often occurs with differential settlement
Shallow and deep foundations Shallow footings are used where soil conditions are stable and where the required soil bearing capacity is adequate close to the surface of the ground. Load is transferred vertically from the foundation of the ground Deep foundations are used where soil conditions are unstable or where the soil bearing capacities is inadequate. Load is transferred from the foundations, through the unsuitable soil and down to levels where bed rock, stiff clay, dense sand/grave is found.
Retaining and foundation walls: Retaining walls and foundation walls are used when sites are excavated to create basements or where changes in site levels need to be stabilised. The pressure load of the earth behind the wall needs to be considered to prevent the wall from overturning.
Mass Mass materials: stone, earth, clay, concrete Main properties : hard, compressive strength, good thermal mass, durable These materials are the group which are strong in compression but are weak in tension Mass construction can be: i) Modular: ii) Non-modular -Clay brick -Concrete -Mudbrick -Rammed Earth -Concrete Block -Monolithic Stone -Ashlar Stone (columns and beams) Masonry Masonry materials: stone (slabs, rubble stone, ashlar blocks), clay(bricks, honeycomb blocks), concrete (blocks, commons) Masonry definition: Masonry refers to buildings 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 masonry units Joint: The way units are connected to each other Mortar: Mixture of cement or lime, sad and water used as a bonding agent
Mortar properties: The properties of the unit are to a degree applicable to the built element. In other words, the units together act as a monolithic whole. Masonry Construction –vertical elements 1. Walls
2. Columns/piers Masonry Construction – horizontal and curved spanning elements 1. Beams/lintels 2. Arches
Masonry Construction – Spanning/enclosing elements 1. Vaults 2. Domes
Structural Concepts / geometry and equilibrium Centre of mass
The centre of mass is the point about which an object is balanced. The also can be though of as the point where the entire weight of the object is concentrated. The location of the centre of mass depends on the object’s geometry. This concept is also referred to as Centre of Gravity
Bricks A standard size masonry unit made out of clay. Its proportions may vary slightly depending on types and countries but it will always be a hand sized unit.
Properties of bricks 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 Flexibility and Plasticity Porosity/permeability – Medium – low, becomes soaked only if placed in prolonged contact with water Density – Medium, approximately 2~2.5 more dense than water Conductivity – Poor conductors of hat and electricity Durability – Typically very durable Reusability/recyclability – High, can be used with no change or crushed to be used as recycle aggregate Sustainability & Carbon Footprint – Tends to be locally produced, the firing process adds to its carbon footprint Cost – Generally cost effective but required labour costs should also be considered Clay Bricks Considerations
Bricks are permeable (non-waterproof) Advantages -They can be joined with water based mortar -Adequately ventilated so that any wetness can escape, will not deteriorate
Disadvantages - They absorb moisture and expand overtime >>expansion joint required -Salts and lime from the spoil can be drawn up through the bricks when in contact with the ground. This may cause serious pathologies/ aesthetic problems as efflorescence. Concrete Block Generally it is a standard size masonry unit made out of concrete. It can be extremely heavy weighing around 11kg, compared to a brick that is 3kg. Most of them generally have holes in them, so as to reduce weight, allows insulation, allow for bracing through steel pipes or pouring of cement.
Concrete Block – Provenance Made from cement, sand, gravel and water. The manufacture process involves mixing, moulding and curing.
Concrete Blocks – Units Can be classified as load bearing or non-load bearing. Load bearing block is known as concrete masonry unit (CMU). Typical shapes for concrete masonry units are shown in the adjacent diagrams. The term “face shell” refers to the outside face of the block while the term “web” refers to the interior portions between the hollow cells. Concrete Blocks – Uses Mainly used in the construction of walls both load bearing (structural) and non-load bearing (dividing and decorative walls) TO provide greater structural resistances to lateral loads, concrete masonry units are often strengthened with steel reinforcing bars and then filled with grout.
Concrete Blocks – 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 flexibility and plasticity Porosity/permeability – Medium, some concrete blocks are sealed to reduce the opportunity for some water absorption Density – Medium, approximately 2~2.5 more denser than water Conductivity – Poor conductors of heat and electricity Durability / Life span – Typically very durable Reusability/recyclability – Medium. Sometimes re-used with no change but more often crushed to be used as aggregate in other concrete products Sustainability & Carbon Footprint – Inclusion of recycled and waste products from other
processes allowing a positive reduction in carbon footprint and increase in sustainability for man concrete products Cost – Generally cost effective but labour penalties are often applied as the larger format units mean construction usually progresses at a faster rate Clay bricks vs Concrete Blocks Concrete shrinks over time while cray bricks will expand Concrete blocks shrink for several reasons. The cement paste reduces in volume as it hydrates and drying shrinkage occurs a water is lost to the atmosphere. Clay Bricks tend to absorb moisture from the atmosphere and gradually expand. *Movement Joints are required for each material Stone – provenance – types of stone Igneous stone is formed when molten rock (lava/magma) cools Sedimentary stone is formed when accumulated particles are subjected to moderate pressure. (eg limestone, sandstone) Metamorphic stone is formed when the structure of igneous or sedimentary stone changes when subjected to pressure, high temperatures or chemical processes. (eg marble, slate)
Stone uses As one of the oldest building materials, the uses are very broad. Main uses today include walls (structural and non-structural), paving, cladding aggregates and feature design elements. Stone – properties Hardness – Large range generally igneous is hardest, then metamorphic and then sedimentary Fragility – Largely geometry dependant (thickness to surface area ratio) Ductility – Most stones have low ductility Flexibility/plasticity – Most stones are rigid (very low flexibility and plasticity) Porosity/permeability – Large range (Pumice is very porous, granite is not) Density – Largely depending on stone type, stones are most often used in construction (granite, marble, sandstone, slate, etc) are 2.5 to 3 times more dense than water Conductivity – Stones are generally poor conductors of heat and electricity Durability/life span – Typically extremely durable Reusability/recyclability – Very high, can be re-used with no change or re-worked into new shapes for new uses Sustainability & carbon footprint – transport energy is the main factor (local stones have low carbon footprints) stone sourcing has a high environmental cost Cost – Largely dependant on labour and scarcety (how common/rare the stone is)
Activity: Guided Campus Tour This week, the tutorial groups were taken around the campus and were shown the many different buildings that can be found in Melbourne University. Different architectural styles, designs that were sustainable for the environment, buildings that made it more comfortable for people to reside in, etc. Below are pictures taken during the site alongside with notes made
Low bearing brick wall, there are two types of concretes being used on this wall. One is weather reinforced whereas the other isn’t. This institute has been reinforced with concrete
Here shows of concrete that is being worn away through the harsh weather. The metal inside that has been used to embrace the wall has been exposed due to the concrete being worn away and due to that, even the metal has corroded
In the underground car park, there are many funnel like columns acting as supports, these supports however have water leaking through the concrete and hence the water is reacting with the calcium in the concrete causing the many white like spores can be seen on the metal due to the chemical reaction.
Above these funnel like supports, trees have been planted in the area, it may have been used as a win-win situation where the funnel is able to hold the water for the tree whilst the tree roots are able to hold the column together and keep it from going out of place. However from the picture above it is obvious that one of the inside coatings that separate the water from the metal has been breached and hence water is leaking through.