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.

Yes, this is one of the coolest bridges I have ever seen. Built by J.C. Booth Middle for the Science Olympiad Georgia State Finals in 2003, it placed 3rd. For those of you who don’t know Booth, keep reading.

Booth Middle School has won the Georgia State Finals as a team for longer than I can remember, except for one year. They always have an excellent team, and provide much frustration and motivation for the rest of us.

When I first signed up for Bridge Building, I heard that Booth was the team to beat. So I made up my mind that I would beat them. Well, as a 6th grader and a newbie to Science Olympiad I didn’t know what I was saying.

However, I found out that Booth wasn’t the one to beat for Bridge Building. Rising Starr won that year with a 11.something gram bridge, holding 33 pounds. Chamblee won the next year, and E.T. Booth (not the Booth previously referred to) won in 2002. Booth, however, did win in 2003. This is not Booth’s winning bridge, just a cool one. Then all my hopes came true, when I beat everyone in 2004.

I actually have a picture of Booth’s bridge for 2005 (this year), and it is a nice one. But it didn’t win. Still, I might put it up, as the bridge rules have changed enough so nobody can use that design.

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!

This bridge took 5th place at our regional tournament way back in 2001. It weighed 48.something grams and held the entire 15kg without budging. The bridge was absolutely noiseless throughout testing. Back then, we didn’t test our bridges before competition.

I have no doubt this bridge could have held twice what it did. However, the bridge is no longer in existence. I threw it out after having it sit on my shelf for a couple years. Now I wish I had tested it to failure.

David and his dad did the designing for this bridge. Back then, I couldn’t have told you what a Howe truss was. I have come a long way since then .

The Howe truss is very solid, and has been used in engineering for a very long time. Read more about truss design.

This was one of my earlier bridges. I built it after talking with my uncle, who is a mechanical engineer. He suggested that I try using an I-beam. This was a very good idea, but my construction skills at the time were not the best. In theory an I-beam is excellent for bridges, but I could not make it very well.

I don’t know how much this bridge weighed, but it did not hold very much weight.

I had problems making the two I-beams for this bridge. I had to cut my own strips of wood, and I was not very good at doing that yet. The wood I used was very thin, perhaps too thin. I believe I used 1/32″ x 1/4″ strips.

I could not cut the wood strips very straight, and that was the downfall of this bridge. The pieces to the I-beam were not glued together well at all. I was trying out some unique things with this bridge. And if I had better building skills, it would have turned out much better. In later years I was able to make good I and T beams which performed very well.