Left to Right: My coach, David, Me

The bridge weighed 58 grams if my memory serves me well. It held the entire 15kg with ease. It probably could have held 100lbs because it was so overbuilt. This was at my first every Science Olympiad competition at Gordan College. The bridge placed 2nd. Richards MS placed first. Man, this picture sure brings back memories.

The boomilever broke because of all the force that was applied outwards on the bottom chords. The boomilever simply “split” apart and the loading block fell through. I didn’t anticipate the amount of force that would be pushing outwards. Normally my boomilevers broke at the joint to the attachment base. I later tried to add additional bracing but the boomilever never held more than 10kg. I think at the end of the season I was close to an efficiency score of 1000. My team didn’t make it past regionals that year, so I didn’t have a reason to try for more.

It is pretty easy to see how this bridge failed: the bottom fell out. This is a fairly easy fix, and might have been due simply to poor wood selection. Had I paid more attention to the quality of wood I was using, this failure might have been avoided.

I used two pieces for the arch. I had a square 1/16″ x 1/16″ piece of Basswood for the bottom of the arch. Then I glued a rectangle piece of Balsa wood on top of that to form a T beam. This method worked pretty well, but Balsa is harder to bend than Basswood.

This photo makes the bridge look a little lopsided. That wasn’t the case, however.

Here is a photo of where the bridge broke. Click the picture to get a really good close-up.

As you can see, instead of using X’s, I only have a zig-zag pattern. That was because I wanted to see if I could “trick” the system. In a tower like the one above, the four legs are in compression. When the load is applied perfectly vertically, the rest of the members have no load until the legs begin to twist or bend.

Because the legs are square pieces, they have equal resistant to bending in all directions. The X’s only serve to break the main legs into smaller sections, which increase the strength.

Chamblee has always done well in Bridge Building. In 2001, they won the State finals in this event.

This bridge is from the 2003 GA State Tournament, the same tournament the Booth Bridge is from.

I was never able to fully develop and use this bridge. I got this idea from talking with a Science Olympiad coach in Ohio. Now I wish I had gone ahead and put more work into this. The next year, the bridge rules changed so that I could not use this concept.

The trick was to get the arches to the perfect length, so that they barely fit into the loading device. I had made these arches a bit too long. When I tested the bridge, the arches were already bent out-of-shape, so it did not hold enough weight. I fully believe that this bridge concept can go very far.

As you can see, this bridge had a roadbed, which was supposed to allow a hotwheels or matchbox car to roll freely across. BAD DRIVER!

I still love Scotland’s Firth of Forth bridge, and the famous one from my birthplace, the Golden Gate bridge. But that one that connects Sweden and Denmark is pretty cool! I wonder what it feels/sounds like when going under the water. It must be a freaky feeling.You know, that bridge reminds me of a certain ride in Riven.Ha, was doing some more research on this bridge, and found this:

http://www.snopes.com/photos/architecture/bridgetunnel.asp

For more information on this bridge, seehttp://www.roadstothefuture.com/I664_VA_MMMBT.html

This bridge was built by Michael in Quebec.

I have a bridge I built for a physics for engineers class I’m taking in cegep (QUEBEC). My partner and I didn’t have much confidence in it, but it blew the competition away! The design was a fairly straightforward arch as you can see. We primarily focused on keeping the weight of the bridge down. The bridge weighed in at 211 grams.

The efficiency rating worked as follows:
Weight supported by the bridge divided by the weight of the bridge squared.

This was our score. 173 KG./ (.211)squared. Our score was 3886, second place was 2100 and the rest of the competition was well below 2000. Our bridge held 381 pounds! And the lab class which we tested them in ran out of weight for us to load it with, so we couldn’t break the bridge! our teacher is building a hydraulic system to crush it next week!
~Michael.