Bridge designing
today i am sharing my project on bridge making, which i made for a techfest competition and completed in just two days. My friends had decided to visit iit guwahati for a techfest, at that time i was not interested to participate but then i saw a project/competition for a bridge making but the problem was that when i decided to go for it i had only three days. First day passed in general planning and searching of the materials. I decided to make a truss bridge using popsicle sticks. Task for the competition was like this
Task:
To design a bridge (from home
and not on the spot), made out of Balsa wood, popsicle wood, ice-cream sticks,
tooth pick glue, thread and other materials specified below.
Bridge Specifications:
1. The deck width may vary between a minimum of 250 mm to a maximum of 300 mm.
2. The deck length should be at least 700 mm and no more than 750 mm.
3. There should be a clear space of 250 mm X 250 mm in the mid span of the bridge to apply loads.
4. Construction should not exceed 150 mm below the deck of the bridge.
Materials to be used:
1. Wood (maximum length 200mm and maximum size of the cross section be 15mm x 15mm). Any type of wood can be used.
2. Synthetic white adhesive (polysynthetic resin adhesive) or single component cyano-acrylate adhesive.
3. Thread (only cotton, no other material is allowed).
5. The adhesive should be used only at joints. It should not be applied on the free surface of the member to increase its strength; doing so may lead to penalty of points (penalty will be 20% of your score) or even disqualification.
6. Weight of the structure should not exceed 3.00 Kg.
Testing:
The bridge will be loaded on the mid span.
The minimum load will be 5.00 kg and will be increasing uniformly up to failure.
Take a look at this video.
P.S Failure is defined as: Any physical failure
link for the task http://www.techniche.org/techniche12/#
I got
excited to see a task like this...i started searching for balsa wood near my
institution but was not able to find it there. Then i decided to go my home
town for the completion of task at my
home itself. On first day i collected the materials. Still i was not able to
find the balsa wood i buyed popsicle sticks about half a kg, then collected
some old plywood. Plywood is made by three layers of wood two thin and continuous
and in between it has rough woods and then stuck together. I unsticked those
layers and cut the upper thin layer in 150 mm*15mm size then sticked icecream
sticks on them in a truss pattern with a continuous effort of about 15 hours i
was able to built the main span(beams) only. I had to pick train for guwahati
the same day, i had about two hours to complete the finishing work...
I put these
beams(main span) supported on two tables and then started joining them, took help
of my youngster for the final finishing. Somehow managed to build &
complete the robust task in only 2 days that was the best part of the bridge
building.
Moral of the story is that if you are working difficult task just, be confident that you can do it. And with a continuous & focoused effort u can complete your task in a satisfactory way
Finally the results that matters the most ;
It weighted 0.7kg and holded a weight of 27.7kg before the first failure when tested under the load....
