Week 1 Lecture 1 Key rules: ● Construction principle ● Construction process ● Materials Assessment:: logbook, assignment, exam (open book) and quiz (not so important) Essential equipments: penal, pen, masking tape, a tape measure, yellow trace/ tracing paper, scale ruler (triangle) Experiments in lecture: a piece of paper+ one brick ● Fold
Fold+another shape Star shape
Fold+ shape changes+masking tape
Analysis:The strongest one is the one bonded by masking tape. Masking tape can make the construction stronger (harder structure and construction form). E-learning ● Ching: 02 The building (2.08-2.11) The loads, which imposed on buildings, are dead load, live load, settlement load, occupancy load, static load, ground & water pressure. Important load definitions: Dead load (fixed value): non-lives load, Dead loads are static loads acting vertically downward on a structure, comprising the self-weight of the structure and the weight of building elements, fixtures and equipment permanently attached to it. Eg: roof & floor weight, structural frame weight Live load (can change values): live loads comprise any moving or moveable loads on a structure resulting from occupancy, collected snow and water, or moving equipment. A live load typically acts vertical downward but may act horizontally as well to reflect the dynamic nature of a moving load. Eg: a car is moving on a bridge Occupancy load: it results form the weight of people, furniture, stored material and aother similar items in a building. Settlement load: are imposed on a structure by subsidence of a portion of the supporting soil and the resulting differential settlement of its foundation
Construction overview Case study: Melbourne university design building construction â—?
What do we need to be considered during the construction process? -construction principle -load transfer -material chosen -efficiency -the site process (labors, engineer, who is doing what) -basic science -construction techniques -global language so engineers from different countries can communicate Analysis: Construction is a way of using different materials and construction techniques to make buildings. During the process, we required to consider load transformation (forces). It also must be act under construction principles Materials There are 6 elements we need to take into consideration -strength (strong/weak): Steel is stronger than timber -stiffness (stiff, flexible, stretchy, floppy): concrete (stiff), carpet and rubber (flexible) -shape (mono-dimensional (linear), bi-dimensional (planar), tridimensional): metal (bidimensional), brick/ concrete (tridimensional) -material behaviors (isotropic/ anisotropic) -economy (cheap/ expensive): expensive-transport materials (wood frame is not appropriate in Australia because of the lack of wood resources in Australia) -sustainability â—?
Analysis: local materials are preferred in all the building construction. We are required to think of the properties of materials we needed before starting material chosen Basic structural forces: Compression Tension Load path: Live load
Reaction forces: to be stable with loads (force balance)
Not working towards load
Reaction forces Reaction forces
Analysis: force are always balanced (overall must be zero). Try to avoid unnecessary part, which might cause to material waste
Quiz 1 ●
Compression is a characteristic of mass construction (Mass construction: volume filling the space) Forces defined by direction, sense and magnitude (size). (opposite sense=balance=equal forces ) Why do we use scale? To represent larger elements in smaller format/ to represent smaller elements in a larger format/ for practical reasons Window drawing
Activities in tutorial Materials: medium density timer cube Target: construction: tower
Test 1: triangle base
Reasons: triangle is a very stable structure
The space we cannot fill in
Test 2: circle base Level 1
The shape of circle is easier to be built by using timber cubes
Leave space in order to save more materials Level 2 Cubes in level 2 is to fill the space left in level 1. it is able to main the stability of the building
Analysis: this model eventually failed to catch up with other groups in our class due to the over-large base. We seek for more stable base, which results in slow speed and material waste.
Repeating to fill in space in next level
Destroy this unfinished model Useless part. The cubes in this part may not contribute to the stability of the tower. Similar to the case study in e-leaning video, these cubes does not work towards load. A lot of materials are wasted in this part
Joining other group and make closure At the top, we need to close the column slowly
Level 2 Level 1
Cubes moved towards inside
Analysis: We moved cubes to closer to the center in order to close this column. However, we need to do it gradually. Otherwise, the downward load might be greater than the support load (reactive load). The 'new roof' of the column might fall
On the top We do this to try to get height in the condition of lacking materials
Horizontal + Vertical It can make the structure more stable
Compare with other groups wide
narrow This way can reduce material waste and improve efficiency
They tried different ways of making model. It gain the stability of the tower and enrich patterns
Week 2 E-learning Structural system -Solar system -Frame system (it may be included efficient transfer load to the ground) -Membrane system (catch wind, structural frame, air pocket) Eg. sails, ETFE(a plastic membrane) used in Beijing Olympic -Hybrid system -Surface structural -Solid structure (Materials:mud, brick ans stones & compression forces) ●
Construction system -system: it can be defined as an assembly of interrelated or interdependent parts forming a more complex and unified whole and serving a common purpose -enclosure system (facade, envelop system): it is the shell of envelop of a building, consisting of the roof, exterior walls, windows and doors -structural system: it is designed and constructed to support and transmit applied gravity and lateral load safely to the ground without exceeding the allowable stresses in its members -mechanical system/service system: the mechanical systems of a building provide essential services to a building. eg. water supply system, sewage disposal system , heating and ventilation system, electrical system and fire-fighting system -performance requirement: performance for comfort, insulation, rain, acoustic and maintenance -Aesthetic Qualities (face quality, proportion and color) -economic considerations: affordability, which is included initial cost, maintenance cost and embodied energy -environmental impact ●
ESD and selecting materials -Embodied water: it is total energy (oil water, power) used during all stages of a material's life Eg. household item, transporting, sale & storing them Life cycling: it begins with the extraction of raw materials from earth and end with the disposal of waste products back to the earth or recycled (partially or totally) into other products (Raw material acquisition> primary processing and refining>manufacturing >delivery >construction used and maintenance>final disposal) sourcing>manufacturing>distribution> use> recovery/disposal Recyclability (it always links to resue): it is potential for a product/material to be re-used or transformed into a new product. Carbon footprint: it is measure of the amount of greenhouse gases generated during the fabrication,transportation and use of particular product. (the larger the product, the more positive impacts it has,the less detrimental effect it has) EBS strategies: local material, material efficiency, thermal mass, night air purging, solar energy, wind energy, cross ventilation,smart sun design, insulation and water harvesting ●
Structural joint. -roller joint: ●
Load transferred only one direction. Vertical load only
-pin joint It has two directions on the planar.
-fixed joint (solid joint)
Lecture 2 The definition of force: Force is defined by sense, magnitude and direction. Experiment in the lecture Materials:straws Ex1. Push one straw.
The value of force indicated: 500
Ex2. 4 straws are holding together
The value of force indicated: 200
Analysis: this is due to force diffusion. The force on the 4 straws are only balanced Ex3. Straws are bonded with a plastic lid
The value of force indicated: 300 Downward force
Analysis:the lid act as a fixed joint, which bonded all the straws to force them to work towards on direction. It reduces diffused forces Ex4. Straws have slight angle
The value of force indicated: 500
When straws have slight angle, straws will be able to take more
Analysis: to have slight angle on straws can make the forces work towards one point. It can further reduce the effect of force diffusion. To respond to the stronger downward forces, the reactive force from the ground will larger. It is due to the balance between forces (downward force-reactive force= zero) Ex5. Try different shapes of straw bases
The value of force indicated: 800
Triangle shaped straw base
Analysis: the straw id folded to form a triangle shape. Downward forces are also separated by the foots to work towards different points on the ground. The stability of triangle base and force separation cause the model to take more
The value of force indicated: 200
Analysis: the foots are too separated. The failure of bonding foots together will cause force diffusion Ex7.
The value of force indicated: not work
Analysis: there are only two foots bonded. It will cause force to go two different different directions. This is why it fall, when pressure is imposed to the lid Ex8.
The value of force indicated: ideal
The base is formed by two triangles
Analysis: fixed joint, slight angle of straws and the stability of triangle will make this model very stable. It allows the model to take more. Quiz ● ● ● ●
Cross-ventilation is an ESD strategy, but not frontal ventilation Facade is envelop, which is enclosure system . A fixed joint can restrict any movement, including vertical horizontal and rotation load transformation
Union house (compression and tension)
Tutorial practice Material: basalt wood Target: a tower Plan 1: circle+ fixed joint
Analysis: this plan does not work eventually because the property of the material. Basalt wood is not sufficient flexible and stretchy to make a circle. Many basalt wood breaks when I attempt to make a Circle. However, fixed joint is still a good idea to maintain the stability of the model. It can prevent force diffusion and many movements Plan 2:triangle+ fixed joint triangle
Analysis: in this plan, triangle is chosen due to its stability. On the higher level, I place the higher triangle in different position to test more possibility and patterns
Top view To the top
Testing the model
The corner, which three pieces of basalt wood are connected, are very strong. Compare to that, the basalt wood stick is weaker. The stress imposed by tutor breaks the thin wood stick
Analysis: at the corner, we uses the stability of triangle to stabilize the connecting stick The connecting point are surrounded by 3 small sticks in the model, which forms a triangle
Weak connecting point, which effect the stability of the model
strong connecting point. It is made by two overlapped sticks. Overlapping gains the strength of the materials
Week 3 Lecture -buildings must be fit to the surrounding landscape. Landscape is a very important element in design and construction. Eg. London Olympics Parks -Olympic stadium (the combination of many elements) , which is related to material chosen and engineering solutions -Engineering solutions.
e-learning 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 â—?
-strut (compression):a slender element design to carry load parallel to its long axis. The load produces compression -tie (tension): a slender element design to carry load parallel to its long axis. The load produces tension -beam (both compression (above) and tension(below)):Generally a horizontal element designed to carry vertical load using its bending resistanceâ€”tend to curve -Slab/plate (force distribution): a wide horizontal element designed to carry vertical load in bending usually supported by beam -panel (wall (vertical force)/ shear diaphragm (horizontal force)): a deep vertical element designed to carry vertical or horizontal load Footing and foundations (basement design) -Foundation is the substructure of the building and its function is to safely transfer all loads acting on the buildings structure to the footing system. Foundation must be underground in order to support super structure -shallow footings (normal): they are used where soil condiyion 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 to the ground eg. pad footings, strip footings and raft footings -deep Footings (over-heavy building/ unstable soil): they are used where soil condition are unstable or where the soil bearing capacity is inadequate. Load is transferred from the foundations, through the unsuitable soil and down to levels where bed rock, stiff clay, dense sand/ gravel is located. (distribute building weight) eg. end bearing piles, friction piles (piling system) -retaining walls/ foundation walls/ basement wall â—?
Masonry(basement design) -Masonry (bond, course, joint and mortar) refers to buildings with units of various natural or manufactured products...usually with the use of mortar as a bonding agent. (properties: the units together act as a monolithic whole) ●
Equilibrium is a state of balance or rest resulGng from the equal acGon of opposing forces. In other words, as each structural element is loaded, its supporGng elements must react with equal but opposite forces This means that the sum of the applied and reacGon forces must be zero in order for equilibrium to exist. 1. If the object or system is not moving up or down, then the sum of the verGcal forces must be equal to zero. ∑V=0 2. If the object or system is not moving side to side, then the sum of the horizontal forces must be equal to zero. ∑H=0 3. If the object is not rotaGng, then the sum of the moments must be equal to zero. ∑ M = 0
Published on Mar 20, 2014