CONSTRUCTION WORKSHOP
35mmĂ—35mm Radiata Pine produced in Australia: - Advantages: because the section of this material is a square, the load could be applied uniformly on the material. - Disadvantages: each piece of this kind of timbers has several knots on it that could largely decrease the stability and special consideration need to be made to these points to prevent breaking.
W07 CW REPORT lď Ź MATERIAL & TOOLS Bench hook: tools used to fix the material that needs to be cut and protect the table from other kinds of cutting tools, e.g. saw. Hammer: really heavy! Use hand to fix the nail for the first several trials in order to ensure the direction of the nail is correct. Need great efforts!
Drill: it could be used for producing holes on material or nailing. There are 2 gier, and one is faster than the other one; very efficient, and it could ease the nailing process This tool is used to measure the cutting angle and than draw the angle on material.
Saw: using this tool to cut material need to consider the material loss. Dangerous.
42mmĂ—18mm Radiata Pine produced in New Zealand: - Advantages: there is no apparent knot on it, which could increase the strength of the material. - Disadvantag es: relatively weak in the vertical direction due to it is not thick enough
Plywood sheets: This material is made by thin laminated timber sheets that are glued or pressed in alternative directions (envs10003, w5 m3). Therefore, the material overcomes the disadvantages that timber is weaker in the direction perpendicular to the grain than the direction parallel to the grain (envs10003, w5 m1).
lď Ź STRUCTURAL ANALYSIS NO. 1 TRIANGLE TRUSS
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Failure Mechanism: 1. Wrong material selection: Plywood is weak in compression; however, it is used as the material to experience compression in this structure. If adjustment that to switch the material used in these 3 sides, more load could be borne.
Shape: Triangle Trussďź?a rigid shape and is pretty stable Failure load: 150 kg; Max deflection: 12cm Structural performance: when load is applied to this structure, it will be transferred through 3 directions, the vertical column in the middle that is made by structural timber, and two beams (the sides of this triangle) that are made by plywood. Besides this, 2 reaction forces also act at the basic angles. In this case, tension force is applied to base and compression force is applied to the other sides. Joint: fixed joints: using nails to connect 2 separate pieces
Some adjustments that can be made
2. The structure finally broke on the bottom beam at a short grain,
1m
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No. 2 OUR STRUCTURE
Shape: two beams with bracing between them, and a sheet bracing made by plywood at the outside. Failure load: 180 kg; Max deflection: 15cm Structural performance: because of the unfamiliar with the tools, the final finished structure is not the same as the design. If the structure is finished, the bottom beam will experience tension while the top beam will experience compression Joints: fixed joints made by nails. Because of this structure is pretty incomplete, the material efficiency is not very good. The real load-bearing structure is just the original material. Failure mechanism: the structure was broken at the place where nails were drilled in. The holes created by nails weaken the stability of the whole structure. When force is applied to the structure around the hole, it will break down
1m
No. 3 STRONGEST STRUCTURE
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Failure Mechanism: the bending of the top beam caused by compression force,
Shape: two beams with column between them, and there is a sheet bracing made by plywood at the outside Failure load: 450 kg; Max deflection: 36cm Structural performance: when load is applied to this structure, reaction force will be applied to the structure; therefore, tension force is applied to bottom beam and compression force is applied to top one. During the destroy process, the bending of the top beam cause by compression force and the bottom beam caused by tension could be observed. Joint: Fixed joints fixed by nails
lď Ź MODEL V.S. ACTUAL MATERIAL Model making material: - relatively smaller and lighter - they are usually easy to put together by using small pins and glues. - Can only bear small amount of load
Actual constructing material: - heavy and big. - It is very to build the joint between different part of the structure by just human efforts, and tools are very necessary in this case. - can bear a lot of load
W07 02_REFERENCE LIST Envs10003. (2014, April 1). W05 m1 From Wood to Timber [Video file]. Retrieved from http://www.youtube.com/watch?v=YJL0vCwM0zg&feature=youtu.be Envs10003. (2014, April 1). W05 m3 Engineered Timber Products [Video file]. Retrieved from http://www.youtube.com/watch?v=0YrYOGSwtVc&feature=youtu.be