WEEK 1 Mass Construction Tower This is a challenge in which students are supposed to build the tallest building possible using a wooden block called the Medium Density Fibre (MDS). Components inside MDS are wood dusts (usually gotten from wood chopping left overs) and resin, compressed into a preferable density. This material has light color and is relatively lightweight: enabling the structure of the building to stand firm and not easily blown away by the wind.
An elephant figurine was used in order to develop the ability of students to plan ahead in terms of size and shape of the building. The category was the elephant should be able to enter and move around the building, along with the competition with other groups to make the tallest and most stable building. Below are some notes taken in the building process:
Image 1: steps on how the tower was built
WEEK 1 It is suggested that in making the door for the elephant figurine should be done in the last step after the building is completed, as the blocks in the upper side would have enough weight for the bottom blocks to support the hole (unsupported blocks) in the doorway. Dome-shaped side is less stable compared to straight side; this makes it easier for the door hole to be made in the domeshaped side. The amount of blocks taken out depended on the size of the figurine (Image 2).
Image 2: steps on how the doorway was formed
In regards of the stability between the domeshaped side and the straight side, it is noted from Ching (2008) that the load will always move downward towards the ground (Image 3). This proves that the straight side of the building supports more weight compared to the domeshaped side (Image 4). Thus, if the doorway is made at the straight side of the building, the whole tower is likely to collapse.
Image 3: how loads work on a figure
Some other examples made by other group are shown below:
Image 4: load path of the tower
Image 5: other examples of the tower
WEEK 1 Paper Pedestal Paper has an amazing strength for a material with high flexibility. It is shown by the ability of a paper to be bent easily, and its ability to hold up a brick when it is formed in certain ways. Paper has strands of fibres within that help it to be flexible without breaking apart unless a large force pulling it apart. Students were challenged to form a pedestal made out of paper to hold up a brick, not less that 10cm high, in order to show the strength of strands in the paper.
WEEK 2 Balsa Frame Tower Students are challenged to build the highest frame tower using strips of balsa wood. Balsa wood is a type of wood that is low in density, very lightweight and has long fibres. According to Robinson et al (2004), wood is an example of anisotropic material, as its properties depended on the way that the wood is cut (along or across the fibres). The fibres have supported the wood gain its strength; therefore it has to be cut along the fibres and not across. It is, too, important to prevent splinters while cutting or working with the wood.
It is important that the base should have a strong support for the whole tower as the tower is going to be tall. Started out with 3 legs for the building and woods are set across each legs to help the base to stand still firmly (Image 1). The base should be wide enough for it to hold up the weight of the tower.
Below are the comparison of tower A, B, and C observed in the tutorial group (Image 2). Balsa tower A and C has similar structure. The only difference is that the size of the triangular frame is bigger in tower A than C. As the result, tower A can stand for a longer time compared to tower C that collapsed within several minutes. This is resulted by the inability of the triangular frame to support the weight of the long rod glued at the top. Tower B, however, cannot be compared with both tower A and C as it does not have the same height compared to other towers.
Image 1: first step in making tower A
Image 2: graphical comparison of 3 models
Image 3: real photo of tower A, B and C
WEEK 2 Compared to all towers, tower A has the least firm structure. It is proven by the bending in the joint of the frame that happens in tower A but not in other towers (Image 4). One reason is that tower A has jointed wood strips (Image 5) whilst other towers do not. Secondly, the way by which the two wood strips are joined together is not strong enough for it to hold the weight of its load within the triangular frame structure (Image 6). And finally is the thickness of the strip used as the it goes up the tower; middle part uses thinner strip compared to upper part, making the centre of the structure to collapse as the thin strip cannot hold up the weight (Image 7). In tower B, it is presumably to be the strongest structure because each wood strip supported securely by putting another strip at the centre of each strip; this helps the frame reduce its tendency to move and thus it is less flexible. Tower C has similar structure with tower A. However, the small size of the structure has made the strips to be strong enough for it to hold the load within the triangular frame structure.
Image 4: bending of the frame in tower A
Image 6: joint needs extra support for it to stay straight
Image 5: the way of taping the jointed wood strips
Image 7: the tower collapsed – the middle strip couldn’t support the upper weight
WEEK 2 Water Tank Structure The task in this activity is to build the strongest support for a “water tank� by using 4 straws and needles. The strength is measured by how much weight can the structure support, which is done by pushing the structure downward towards the weight measurer underneath it. The first attempt made by the lecturer was to measure the approximate weight that a straw and a set of straws can hold. It is important that in order to reach the maximum strength, the straws have to stand straight, as the load will be transferred down the plastic straw and not to the space in the middle or outside.
KNOWLEDGE MAP Strength: Measured in regards of compression and tension
Behaviour: Properties of a material that defined in the direction of its components (isotropic and anisotropic)
Shape: Classified into monodimensional (linear), bidimensional (planar) or tridimensional (volumetric)
Stiffness: State of a material that is flexible or stiff
Static: 1. Accumulated slowly without fluctuating rapidly in magnitude or position 2. Deformation occurs when static force reaches a peak 2. Live loads – comprise any moving or movable loads, may act vertically downward and horizontally 3. Dead loads – comprise self-weight of the structure and building elements permanently attached, acting vertically downward
Fixed: Resists movement, but it can bend as some materials can expand
Pin: Takes out moment forces, relies on tension between joint and material
Structural Joint
Roller: Allows load to move in one direction, usually for expansion and contraction
Construction Material
Dynamic: 1. Applied suddenly, rapid changes in magnitude and point of application 2. Structure develops inertial forces in relation to its mass 3. Maximum deformation does not correspond to maximum magnitude of applied force 4. Wind loads – kinetic energy of a moving mass of air 5. Earthquake – series of longitudinal and transverse vibration in earth’s crust
Loads Construction: 1. Performance requirements 2. Aesthetic qualities – desired relationship of building to its site in terms of form, massing, color, pattern, texture and detail 3. Regulatory constraints – compliance with zoning ordinances and building codes 4. Economic considerations – initial cost and life-cycle cost 5. Environmental impact – conversation and efficiency of resources and energy 6. Construction practices – sets of safety standard Enclosure: 1. Shell or envelope of a building 2. Consist of roof, exterior walls, windows and doors 3. Protect from moisture, heat, airflow and noise 4. Access for light, air, views and people
Mechanical: 1. Provide essential services to a building 2. For water supply, sewage disposal, heating, ventilating, air-conditioning, electrical, vertical transport, fire-fighting, waste disposal and recycling
Building System
Structural: 1. Support and transmit applied gravity and lateral loads to the ground 2. Vertical extension of a building above the foundation
KNOWLEDGE MAP Water Harvesting
Insulation
Thermal Mass
Local Material
Material Efficiency
Environmentally Sustainable Design Night Air Purging
Wind Energy
Smart Sun Design
Solar Energy
Cross Ventilation
GLOSSARY Load path
The interconnection of all wood framing elements of the lateral and vertical force resisting systems, which transters forces to the foundation
Masonry
Stonework or brickwork
Beams
Rigid structural members designed to carry and transfer transverse loads across space to supporting elements
Reaction force
A force having equal magnitude and the opposite direction along the same line of action as the original force
Point load
A load concentrated over a tiny area
Compression
The state of being compressed, or being shortened by a force
Structural joint
Connectors used to joint the structural elements in the form of a point, a line, or a surface
Stability
The resistance of a structure or element thereof to withstand sliding, overturning, buckling or collapsing
Tension
The state or condition of being pulled or stretched
Frame
The timberwork or steelwork that encloses and supports the components of a building
Bracing
Structural elements installed to provide restraint or support (or both) to other members, so that the complete assembly forms a stable structure
Column
A relatively, slender structural compression member such as post, pillar, or strut, supporting a load, which acts in (or near) the direction of its longitudinal axis
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BIBLIOGRAPHY Ching,!F.!D.!K.!(2008).!Building(Construction(Illustrated((4th!ed.).!Danvers,!MA:!John!Wiley!&! Sons,!Inc.! ! Harris,!C.!M.!(2006).!Dictionary(of(Architecture(and(Construction!(4th!ed.).!United!States:! McGrawJHill.! ! Robinson,!R.!B.;!Kerr,!J.;!Noschese,!F.;!Klein,!N.;!Belasen,!A.!(2004).(Cracking(Dams.!Retrieved! from!http://www.simscience.org/cracks/glossary/isotropic.html! ! WebFinance!Inc.!(2014).!Continuous(load(path.!Retrieved!from! http://www.dictionaryofconstruction.com/definition/continuousJloadJpath.html!