APPENDIX
CONSTRUCTION WORKSHOP
CONSTRUCTING ENVIRONMENTS
CHAN JOSHUA TIG HAY 638994
TOOLS REQUIRED 1. Hammer
2. Saw
Definition: an instrument consisting of a solid head, usually of metal, set crosswise on a handle, used for beating metals, driving in nails, etc. (Macquarie Dictionary 2003)
Definition: a tool or device for cutting, typically a thin blade of metal with a series of sharp teeth (Macquarie Dictionary 2003)
Explanation: It is used to drive nails into the wooden planks (probably plywood) such that it can secure 2 pieces of wood together
Explanation: They are used primarily to cut wood in this workshop. There are three types of saws, one is used by pulling the saw to cut wood, one is by pushing and another which can be used be both pushing and pulling.
3. Tape-measure Definition: a measuring instrument consisting of a narrow strip marked in inches or centimeters and used for measuring lengths; "the carpenter should have used his tape measure" (Farlex 2004) Explanation: It is used to measure out smaller segments of wood for cutting.
CONSTRUCTING ENVIRONMENTS
CHAN JOSHUA TIG HAY 638994
STRUCTURAL MODEL Physical Properties Length: 110cm Width: 7cm Depth: 10cm
Composition: Two 160cm long wooden planks sandwiching three layers of shorter wooden planks segments, a piece of plywood is attached at the back of the beam. Structural properties: Strong in compression in the centre of the beam, but with weaker cohesion near the area where there are voids due to the lack of support.
CONSTRUCTING ENVIRONMENTS
CHAN JOSHUA TIG HAY 638994
STRUCTURAL MODEL STRUCTURAL PERFORMANCE
FAILURE MECHANISM During the destruction process, the wooden planks bend in the vertical direction and experienced bending stress while the thin strip of plywood at the side acted as a resisting moment but gradually bended horizontal outwards.
The beam is designed to focus on resisting compression at the centre, and thus it is strengthened by adding three layers of smaller plank segments between the two long strips. Due to the limited amount of resources, only smaller plank segments are available to create the layer leaving voids in between. The thinner plywood which is attached to the back of the beam aims to resist the bending moment that will occur when a force is applied to the centre.
The beam finally failed by breaking into three segments, which are basically the centre part and the two sides where there are three layers of planks. The crack which triggered the failure happened in the plank where the voids were present. Therefore the existence of a void meant that the wooden plank lacked support when it was in tension, causing transverse shearing to occur in the part that is not thickened. (Ching 2008) In addition, the plywood alongside of the beam bended in a horizontal direction and experienced a crack and was detached during the early stage of the destruction process. This was due to the fact that the screws used to fasten the plywood were too thin and short, which made the loosening of the screws much easier.
CONSTRUCTING ENVIRONMENTS
CHAN JOSHUA TIG HAY 638994
DESCRIPTION OF KEY CONCEPTS Span The spanning capability of horizontal elements determines the spacing of their vertical supports. (Ching 2.20)
Flexion Flexure is the bending of a material under load application. (Interactive structures 2008)
Cross section A section formed by a plane cutting through an object, usually at right angles to an axis. (The Free Dictionary, 2004)
Shear A shear force is an effect that is developed from the action of opposing forces. Shear forces produce simultaneous shifting of horizontal and vertical parallel planes of a material, and cause deformation. (Interactive structures 2008)
Strength Strength is a property of a material that affects how applied forces cause deformations to the material. (Interactive Structures 2008) Compression A compression force causes the particles of a material to become more compact among each other. (Interactive Structures 2008) Tension Tension forces stretch and elongate a material. It causes particles composing a material to move apart. (Interactive Structures 2008)
CONSTRUCTING ENVIRONMENTS
Deflection Deflection is the perpendicular distance a spanning member deviates from a true course under transverse loading, increasing with load and span, and decreasing with a increase in the moment of inertia of the section or the modulus of elasticity of the material. (Ching 2.14) Buckling Buckling is the sudden lateral or torsional instability of a slender structural member induced by the action of an axial load before the yield stress of the material is reached. (Ching 2.13)
CHAN JOSHUA TIG HAY 638994
REFERENCES Ching, F.D.K 2008, Building Construction Illustrated, John Wiley & Sons, Inc., New Jersey Farlex 2004, Farlex Inc., Huntingdon Valley viewed 30 August 2013, <http://www.thefreedictionary.com> Macmillan Publishers Australia 2003, Macquarie Dictionary Publishers Pty Ltd, Australia viewed 30 August 2013, < www.macquariedictionary.com.au> Interactive Structures 2008, DVD recording, John Wiley & Sons, Inc., New Jersey
CONSTRUCTING ENVIRONMENTS
CHAN JOSHUA TIG HAY 638994