Elevated Bridge B/C

[bridgebuilder25]

How many PA bridges didn't break? Ours didn't.

the humidity messed with my bridge and caused it to break slightly early. when i tested it back at home it held more than it held at states. (i didnt test it to 15 kg, just to the efficiency that i wanted to make sure it could get) if it had held what i had expected, it would have gotten a 1333 efficiency which would have won the state.

[nejanimb]

Ours broke. We were hoping it wouldn't, but the things I already mentioned about the test apparatus meant it broke at 13kg.

[andrewwski]

I still don't understand the preoccupation with not breaking the bridge. I always want the bridge to break. Unless you're good enough to build a bridge that holds exactly 15.0 kg and no more, you're overbuilding the bridge when it holds all the weight. Because the bridge can hold more then, but you can't load it that much.

And there's nothing different about having a 10 gram bridge that holds 15 kg or a 5 gram bridge that holds 7.5 kg. The efficiency is the same.

I never built my bridges to hold the entire weight, because that's overbuilding and not getting the maximum efficiency possible out of the bridge.

I like to walk home from competition with a bridge that is in a million pieces.

[Aia]

Well, I prefer aiming for 15kg bridges for two reasons: one, I am more consistent at building a heavier bridge that holds more weight rather than a light bridge that holds less weight. I have also found that lighter pieces of balsa aren't as likely to be uniform as heavier pieces. Two, what if your bridge does have a weak spot? Hopefully the extra strength can compromise for any inconsistencies in the wood.

Of course, the best scenario would just be having a super light bridge that takes the 15kg. : )

[nejanimb]

We actually have been aiming for the 14 or so area. If you don't hold most of it, there's no real way to get high scores without running into issues with wood inconsistencies and expense problems (the lightest balsa usually costs more). Of course, when we design our practice bridges to hold about 13 or 14kg, we still always hope the competition bridges hold the whole weight, since that means the scores are higher!

[jander14indoor]

Just FYI, MI state results from yesterday. From the event supervisor (I was running another event). Winning efficiencies were in high 1400 range.

Jeff Anderson
Livonia, MI

[croman74]

I did terrible yesterday. My bridge broke way earlier than expected.

[sxnhe]

Just FYI, MI state results from yesterday. From the event supervisor (I was running another event). Winning efficiencies were in high 1400 range.

I was waching MI elevated bridge yesderday. In C devision, the 1st place was Troy HS with efficiency 2100+. The secend place was West Ottawa at 1500+. These two teams got third and fouth overall place and won't go to the national. The next two teams with efficiency at 1400+ will go to the national.

[croman74]

Troy got 2100? That's amazing! I didn't hear any scores other than mine.

[nejanimb]

Wow - I'm sort of surprised to hear that Grand Haven didn't bring anything 1500+. Congrats to Troy HS on an impressive score... that puts them high up there nationally for best scores. Good for them!

It's somewhat surprising to hear how many top schools seem to have less than fantastic bridges this year... Not sure about Troy in CA, but Grand Haven didn't break 1500, none of the top Ohio teams broke 1500, Fayetteville Manlius in NY didn't, Penncrest in PA didn't, Poudre in CO didn't... maybe they've improved - we'll just have to see at nationals!