LOG BOOK- WEEK 2- STUDIO REPORT #2 FRAME TASK: In a group of three we were instructed to construct a stable and sturdy structure that was of length 1500mm and able to bridge this length using one 600mm x 100mm piece of balsa wood. LEARNING OUTCOMES: It was intended for us to learn about the importance of frame construction. How load paths act within frame structures was focused upon as well as structural joints. MATERIAL: We were supplied with a number of materials: •
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One piece of Balsa Wood 600mm x 100mm Glue Pins Blue Tack Cutting Matt Retractable Knife
DESIGN: We spent a few minutes discussing and formulating design plans and our design concept. We decided to sketch our design before cutting our piece of balsa as we realized once it was cut we could not remedy the wood.
IMAGE 1. LOW WARREN TRUSS
IMAGE 2. LOW PRATT TRUSS.FULL SLOPE
We toyed around with a number of designs but narrowed it down to a Truss design; both Warren Truss (IMAGE. 1) and Pratt Truss (IMAGE. 2) were initially considered. We later agreed upon a “Low Warren Truss” concept, as we feared we might not have enough Balsa to achieve a Pratt.
IMAGE 3. FINAL AGREED DESIGN
ARRANGEMENT: Warren Truss Bridge designs are the most commonly used. A Truss frame is most suitable in the construction of bridegs as they can withstand both compression and tension applied by loads. • •
Trusses follow the rule of Newton’s Laws of motion. Truss’ commonly utilize ‘Pin Joints’ (IMAGE. 4)
IMAGE 4. PIN JOINT In our Warren Truss Bridge design, Vertical linear components are in tension whilst Diagonal and top linear components are in compression (IMAGE.5). Central Vertical linear components thus act as support for compression from above and help to prevent buckling.
TENSION COMPRESION COMPRESION IMAGE 5. DEPICTION OF TENSION A ND COMPRESION
RESULTS: Our bridge components were not parallel. And so did not balance and sit between the 1500mm gap as it would simply topple and flip upside down. If we were to do the task again we agreed it would be best if we took more care with the consistency of our components lengths and other dimensions. It was however technically sound and demonstrated the desired learning outcomes.
DECONSTRUCTION: We were pleased to discover that, when held to sit between straight (as our bridge lacked parallel components), it withstood a great deal of weight, a total load of thirteen blocks, before collapsing.
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