Elevated Bridge B/C

Re: Elevated Bridge B/C

Postby Aia on Fri Jul 17, 2009 5:18 pm

Has anyone seen the draft rules for Elevated Bridge for the coming season?
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Re: Elevated Bridge B/C

Postby Balsa Man on Tue Jul 21, 2009 7:57 am

Sorry 'bout dropping into a black hole for the last.....few weeks; way too busy at work, but in these economic times that's a good thing I guess.

Skimming over postings, a few quick things-

I will get a picture up of the 3 load-point bridge up within the next couple weeks.

On the safety tower - Jeff, thanks for the.....appreciation of what it allows you to do. Its the closest thing to magic I've found over the years. Clarification, its not so much that it slows failure down so you can see it, but that it stops it right after it ocurrs. You can/should adjust the length of the upper chain (the slack in the chain) so the block can fall.....just enough to allow failure. With a very rigid bridge a 16th or just a tad more is enough; if its more flexible, a little more;maybe up to 1/8th. When we tested Peter's State bridge to failure, we were at about a 16th. One of the upper compression members (top cross pieces) broke - right at the edge of the load block - at the point of highest compression load, where the diagonal compression truss member from below joins the top compression member. 1/8th square stock, one end of the break displaced down - the ends of the break are actually still connected w/ wood fibers. Jeff has it exactly right - in terms of using this tool - where you would go from this point; fixing, and continuing to test the same bridge. In this case, carefully pulling the break back in line, putting "splint" pieces on - and splinting/strengthening the .....corresponding places - the other three places where the top member and compression truss pieces join. With those places strengthened, the next loading will a) more than what caused failure the first time - with that area/member/joint strengthened, and b) will be somewhere else - the next weakest place.

On the question on dimensions on the tower, it really doesn't matter; whatever will fit on the test base you use, and clear the structure you're testing, and is steady/stiff enough to hold a 15kg load without visibly flexing - just look at the photo in the gallery.

Looking forward to hearing how the new rules come out, too!
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Re: Elevated Bridge B/C

Postby smartkid222 on Tue Jul 21, 2009 12:59 pm

Aia wrote:Has anyone seen the draft rules for Elevated Bridge for the coming season?


http://soinc.org/event_rotation
i don't believe there will be draft rules. just the official rules when they come out.
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Re: Elevated Bridge B/C

Postby Aia on Tue Jul 21, 2009 1:55 pm

smartkid222 wrote:
Aia wrote:Has anyone seen the draft rules for Elevated Bridge for the coming season?


http://soinc.org/event_rotation
i don't believe there will be draft rules. just the official rules when they come out.


If your coach goes to the summer institute in Arizona, he receives draft rules for every event. The recent summer institute finished on July 17th I believe, so I thought somebody on the forum may have seen the draft rules already.
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Re: Elevated Bridge B/C

Postby croman74 on Tue Jul 21, 2009 3:11 pm

I'm guessing rjm has seen them, but who knows if he'll come online.
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Re: Elevated Bridge B/C

Postby jander14indoor on Tue Jul 21, 2009 3:52 pm

Or like me wouldn't say if he had seen it as it really isn't that important now. They are DRAFT and very likely to change as a result of that very conference. If you are trying to get a jump on things, just use last years rules and try to match your winning state or national levels of performance. You'll be able to easily adapt to any rules if you can do that. Heck, if you practiced to the old boomilever rules and achieved national levels of performance you'd be able to adapt to the new bridge rules better than 90% (arbitrarily large percentage, not scientifically based) of your competitors.

As to why I'm sensitive, I've had to disqualify too many students because they brought devices to a tournament to the summer draft rules. I'm just not going to perpetuate that.

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Re: Elevated Bridge B/C

Postby Aia on Wed Jul 22, 2009 2:09 am

For curiosity's sake, what variables had event coordinators considered changing? I understand if you can't release any such information, but I was just wondering.
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Re: Elevated Bridge B/C

Postby rjm on Wed Jul 22, 2009 7:12 pm

Jeff is right, talking about specific details in the draft may be misleading. The rules will be final when the ink dries in the books. Anything written here is premature and unofficial. We don't need to make problems for teams or officials with changing information.

Having said that, you can keep in mind that tournaments don't like to invest in new hardware every year, so it's unlikely that the testing apparatus will change. This is still a relatively new event, so don't expect parameters to change drastically. It was mastered by few.Things that are easy to change are height, clearances, loads, detailed dimensions, stuff like that. The general concept won't change so much, so whatever you were working on last year will make a decent starting point. Whatever you actually built for last year will probably not be directly usable, but that really doesn't matter for now.

Take a break, you deserve it.

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