Elevated Bridge B/C

[Aia]

Obviously that design wasn't anything serious...but that form of lateral bracing isn't very effective. Try X's next time.

I think the toothpicks' length and rigidity provided some limitations there.

[dudeincolorado]

no invataionals here cept for one in C ummm regionals early march states late april

[Earthsci_dude]

I've thought about arching balsa... but it seems very difficult. To get a perfect arch, the balsa would have to be the same density throughout the stick, then multiply that by two for each side. When a friend of mine was competing in gliders, she told me that she baked the balsa somehow to get the arches.

What advantage would an arch give anyways? Would you be gaining strength or losing mass by using them?

Besides the A frame, I've also built a bridge that looks similar to the example on the rulesheet. However, I changed up the crossbeams and main supports to what I thought would be more efficient.

i tried to and arch design for bridges my first year in sci-o (even tried to bend bass) and it worked.. but it was way too much work. we spent like the first 2 months of the season trying to create a way that worked, we ended up with this complex bending devise, but i wouldn't ever try doing that again. (even tho an arch design would make alot of sense for E-bridge this year)

also, if anyone is interested, i got the efficiencies for e-bridge in IL this year (it was a trial event at state)
only like 10 teams ended up entering a bridge.. and alot of them seemed to be put together at the last minute, but the winning score was only about 800-ish (also with diff. rules than these draft rules)

[Pleiades]

The top score was only 800?? thats good!! i was scared after seeing the top boomilever and tower scores and wondering how i'm going to be able to do that with an elevated bridge. I knew they would be lower than the boomilever and tower scores but i didnt know it would be THAT much lower. 800 seems very do-able.
What were some of the other top scores?

[Earthsci_dude]

The top score was only 800?? thats good!! i was scared after seeing the top boomilever and tower scores and wondering how i'm going to be able to do that with an elevated bridge. I knew they would be lower than the boomilever and tower scores but i didnt know it would be THAT much lower. 800 seems very do-able.
What were some of the other top scores?

im pretty sure it will get much higher than that tho... it was only a trial event... so it didn't count. i'd guess that top scores will beat out boomi scores, but maybe not top tower scores? we'll see i guess.

[Aia]

After testing 3 bridges yesterday, I would agree that bridge efficiencies may be higher than boomilever scores.

[Pleiades]

How much did yours hold? How much did it weigh?

[Aia]

Sorry, but I can't post my masses/weight held/efficiencies here. I wish I could, but this event is awfully competitive in my state.

I can say that we've all identified the problem: the distal ends sliding out and away from each other. I tested one bridge that must have deflected 8cm downwards before breaking, in addition to each end sliding 4cm out away from each other. It was really quite the spectacle.

[Pleiades]

That's fine, i understand. I have a feeling this event is also going to be really competitive in my state since the team from my state got 4th place in towers at nats so obviously they know their balsa

[spalding458]

Example bridges from Science Olympiad Camp:

http://i168.photobucket.com/albums/u165 ... 2_1815.jpg

This was my bridge. I used a combination of end and notched joints and for glue I used a medium CA.
http://i168.photobucket.com/albums/u165 ... 0_4265.jpg

This bridge was another design from my team.
http://i168.photobucket.com/albums/u165 ... 0_4266.jpg

I believe this bridge was one of the top three at camp:
http://i168.photobucket.com/albums/u165 ... 0_4292.jpg

This design would've done well, but the bridge was too long and I think they used hot glue:
http://i168.photobucket.com/albums/u165 ... 4_2758.jpg