Elevated Bridge B/C

[sewforlife]

I'll definitely stay with bridge next year. It's just too good of an event to not do it. Even over the summer, I think I'll continue to build more bridges, just so that I can experiment different ways and get a head start for next year. Sure the rules might be different, but you can just modify the specs on your design and it should be fine.

yeah, bridge is one of those events that u can build extra of, so that u cna test them and see what things do and don't work. for an event like scrambler u wouldnt want to waste your time building something not up to specs

[croman74]

I don't even do much for scrambler anymore. Once it's set, all you have to do is hope that it goes well at competition. But for bridge, you can always improve. You can never stop working. That's what makes this event so great.

[sewforlife]

I don't even do much for scrambler anymore. Once it's set, all you have to do is hope that it goes well at competition. But for bridge, you can always improve. You can never stop working. That's what makes this event so great.

and many times, very stressful. because only one person can work on the bridge at a time, so it just depends on how fast or not u want to work.

[croman74]

I don't have a partner for bridge. I just build it myself. I think that it wouldn't be good to have 2 people building the same bridge because 1. The bridge won't be even on both sides because different people cut differently, use different amount of glues, etc. 2. You would have to meet to finish building a bridge, which in my opinion is a waste of time and 3. While you build one bridge your partner could be building another bridge that you don't have time to build.
That's why I prefer to work alone. Then for competition, my coach just throws someone on the event with me to fill up the empty space.

[sewforlife]

I don't have a partner for bridge. I just build it myself. I think that it wouldn't be good to have 2 people building the same bridge because 1. The bridge won't be even on both sides because different people cut differently, use different amount of glues, etc. 2. You would have to meet to finish building a bridge, which in my opinion is a waste of time and 3. While you build one bridge your partner could be building another bridge that you don't have time to build.
That's why I prefer to work alone. Then for competition, my coach just throws someone on the event with me to fill up the empty space.

oh, usually me and my partner both build bridges, so that we can test different designs. like one person was good at making arches, so he built only arch bridges until we figured out wat was bad about it. then, at competition, whoever's bridge it is gets to load the sand, while the other person steadies the bucket and watches the bridge, giving the loader advice. etc.

[croman74]

I don't have a partner for bridge. I just build it myself. I think that it wouldn't be good to have 2 people building the same bridge because 1. The bridge won't be even on both sides because different people cut differently, use different amount of glues, etc. 2. You would have to meet to finish building a bridge, which in my opinion is a waste of time and 3. While you build one bridge your partner could be building another bridge that you don't have time to build.
That's why I prefer to work alone. Then for competition, my coach just throws someone on the event with me to fill up the empty space.

oh, usually me and my partner both build bridges, so that we can test different designs. like one person was good at making arches, so he built only arch bridges until we figured out wat was bad about it. then, at competition, whoever's bridge it is gets to load the sand, while the other person steadies the bucket and watches the bridge, giving the loader advice. etc.

That's what I meant in my 3rd point. Instead of having both work on the same bridge, they should work on different designs. But I don't have a partner, so that's not an option for me. But I think that it's a waste of time to have 2 people working on 1 bridge. On my team, there are three 7th graders working as a group to build bridges. But they work on 1 together, and to me that's a waste of time.

[sewforlife]

oh, usually me and my partner both build bridges, so that we can test different designs. like one person was good at making arches, so he built only arch bridges until we figured out wat was bad about it. then, at competition, whoever's bridge it is gets to load the sand, while the other person steadies the bucket and watches the bridge, giving the loader advice. etc.

That's what I meant in my 3rd point. Instead of having both work on the same bridge, they should work on different designs. But I don't have a partner, so that's not an option for me. But I think that it's a waste of time to have 2 people working on 1 bridge. On my team, there are three 7th graders working as a group to build bridges. But they work on 1 together, and to me that's a waste of time.

yeah it is. doesnt that just make the bridge uneven?

[croman74]

Their bridges are pretty even, but they aren't strong or lightweight.

[Balsa Man]

To chime in on the discussion of whether two people can, or should, build a bridge together….. It ties back to one of the fundamentals of doing seriously competitive work:

The power of the jig

It is possible to build a…….decent bridge; 500, 600, maybe even 750 efficiency structure with minimal jigging – like foam board with pins, or laying up on waxed paper over a drawing – for building the sides. When you star pushing 1000, or over, it has to be precise and symmetrical; where both sides come out the same, within, oh, 1/00th of an inch or less. You should be able to take the two sides and put them together, and not see or feel any difference. I posted earlier some discussion on how to build a jig that will get you this sort of precision – check back in this thread.

The same sort of precision is needed in putting the two sides together. First, the sides need to be parallel (length-wise). The ends (the feet) need to be lined up (so they form a rectangle- not a parallelogram). What is harder is dealing precisely with the sides, in top to bottom alignment. It is fairly easy, using boards of various thicknesses, to get something that will hold the sides vertical and parallel. However, with an elevated bridge, you are asking for trouble if you leave it at that. Check out YouTube, and you will see many bridges failing because they tip over. Saw the same thing at both Regionals and State. If the sides are parallel (top to bottom), any force/load that is not absolutely straight down (i.e., any bucket swing, or if the top of the bridge is not absolutely level) will put you in an unstable mode; over it will go. Our guys leaned the tops in by 3/32” on each side. When you look at it, you don’t see it; the sides look parallel. This allows a little bit of side-to-side loading without things getting unstable. Getting a jig that gives you the same lean-in on both sides is…..not easy. You’re going to have to think about it, and you’re going to have to measure and build very carefully. However, it can be done, and it will give you a huge advantage.

So, finally, back to the question of more than one person building. If you have taken the time to build good jigs, then two people can build two sides that are dimensionally the same. Yes, there may be some difference in glue, but that can be…..matched up by doing some “practice joints” together. By using what we call “guide pieces”, two people can cut virtually identical lengths, with the end angles the same. For his bridge, my son has a set of basswood pieces that fit the jig perfectly. By using a razor saw held vertically, putting the guide piece on top of the stick you’re cutting a bridge piece from, putting the saw up against one end of the guide piece, cutting, then making sure the cut end is perfectly aligned with the end of the guide piece, and doing the same thing at the other end, you get a cut piece that is the same length, with the same end angles, as the guide piece. Put the two pieces together; feel the ends with your fingers. They should feel the same length. Your fingers can feel a few one thousandths of an inch. If the pieces don’t come out the same, then cut another one.

Taking this approach really paid off this year. Between Regionals and State, my son got sick- actually, got sick, got almost well, infection came back; a real drag. Schoolwork was stacking up, he had other events to try to get ready for, the clock was ticking. In previous years, my son was the builder, and his partner was the bucket steadier. His partner was able to come over a couple nights, and put one side together. They worked together on putting the two sides together. Putting the two sides together, and actually in a couple steps doing the construction of the sides, there are times where 4 hands can be really helpful.

End result, a 10 gr bridge, that held 15kg; that really was built by 2 guys……

Len Joeris
Fort Collins, CO

[sewforlife]

Thanks for the advice. Yeah, I would agree, having four hands instead of two would help to put the two sides together