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viraj30

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I have an upcoming assessment in Civil Structures. I have to make a bridge out of balsawood (5mm x 5mm) with the help of PVA glue, pins, hacksaw, silicon carbide paper. Suggest length is 350 mm. It has to be STRONG and LIGHT..which designs should I use??
 

Shadowdude

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I have an upcoming assessment in Civil Structures. I have to make a bridge out of balsawood (5mm x 5mm) with the help of PVA glue, pins, hacksaw, silicon carbide paper. Suggest length is 350 mm. It has to be STRONG and LIGHT..which designs should I use??
You're the Engineering studies student.

May I suggest a suspension bridge?
 

viraj30

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how would u make suspension cables? using balsawood sticks would make it weak because they are already bent wudnt it???
 

viraj30

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balsawood and paper? ugly combination..i am thinking of truss bridges cuz triangles are strong
 

Shadowdude

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(I'm playing devil's advocate)

Truss bridge, eh? That sounds good. Interlocking triangles... yeah, and you can make it pretty too.
 

viraj30

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now i have to think of best design that would distribute the weight most uniformly!
 

emamab

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do a warren truss, they are the easiest and wont bend/twist as easily, remember that is what breaks most bridges. were making ours out of paddle pop sticks :D:D:D
 

lusiv

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I used the warren truss bridge it was 32cm long, weight was 55 grams and held 9kg (moving load) but I used gorilla glue, dries in seconds :)
 

D94

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Warren Truss bridges with proportionally and accurately cut pieces of balsa wood with cardboard gusset plates.
 

mitchy_boy

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Just get some steel and weld it together, then stick some balsawood on the outside.

NO ONE WILL EVER KNOW
 

viraj30

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^^its gonna make it heavy! and how will u drill a balsawood piece through 5mm x 5mm??
 

big crocodile

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Do you have any wood that kinda flexible that can be use as an arch? Coz I think arch is kinda strong. My assessment dued last thursday, I had 4 arch for my bridge my bridge supported over 149 kg.
 

viraj30

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Do you have any wood that kinda flexible that can be use as an arch? Coz I think arch is kinda strong. My assessment dued last thursday, I had 4 arch for my bridge my bridge supported over 149 kg.
how much did it weigh??? and can u upload a pic that resembles your design?
 

big crocodile

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how much did it weigh??? and can u upload a pic that resembles your design?
there you go. IMG_1122.jpg

Its just made out of wood and glue (gluegun) but apparently its not balsa wood. Its supposed to have towers as well but I ran out of time. Kinda messy. My advice is spend your time wisely cause most pple in my class ran out of time too.
 

big crocodile

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looks reallyy heavy..


yeah but other bridge were pretty much the same weight e.g IMG_1126.jpg

the thing is how much load your bridge can support. My bridge came first with 149kg and its not even broken yet. The second one was 99kg. You may not believe me but yeah, my bridge looked simple yet strong. It reckon because of the arch.
 

Aquawhite

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Do you have any wood that kinda flexible that can be use as an arch? Coz I think arch is kinda strong. My assessment dued last thursday, I had 4 arch for my bridge my bridge supported over 149 kg.
Balsa wood arches seem to work extremely well. I've seen the design before reinforced with a few other pieces of balsa and paper. It's a strong design.
 

big crocodile

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Balsa wood arches seem to work extremely well. I've seen the design before reinforced with a few other pieces of balsa and paper. It's a strong design.
see :D

still, you should do what you like best. cus the most important thing is you should enjoy doing the bridge otherwise its not gonna work.
 

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