Dombiggers 1st bridge

By on April 17, 2011 -- Modified on October 4, 2016

As you can see i took your advice on using a t-shape for the bottom cord. Which was really cool, cause it gave me a lip for my cross members. I did sandwich the top cord. I glued lap joints and gusset plates, plus pinned the legs to the cords with small wire nails that I cut to size. The model is 19″ long x 2 1/4″ high. The road way deck is 3″ wide. I didn’t weigh it yet. It spans 18″ with 1/2″ end bearings.

Thanks again for all the great info and advice. This project only has to hold 10 lbs. extra credit if it has a 25% or less load capacity percentage. The record in the class on this project is 80 lbs… I’m planning to donate 1$ for every 10 lbs this bridge holds to your web site.

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6 thoughts on “Dombiggers 1st bridge”

  1. This is very interesting! So cool. Good job. Smart idea.

    By Ally -- February 6, 2017
  2. oh btw i did weigh it and it’s 1.9 oz

    By Dombiggers -- April 24, 2011
  3. The bridge looks good, dombiggers. Excellent use of lateral bracing, and the construction quality looks sharp. I don’t often see balsa bridges using pin joints, so I am excited to hear how this bridge performs. Thanks for the donation offer, that is quite generous.

    I am still a little unclear about how the bridge will be loaded. You mentioned a hanging hook. Is that going to connect with the black block looking thing on your bridge? You just want to make sure that the weight is hanging off the TOP of the bottom chord, and not the sticks that connect the sides of the bridge. It looks like that block is resting on top of your bottom chords, which is good.

    By Garrett Boon -- April 17, 2011
    • yes.. i designed it to take the load from the top of the bottom cord. the block is 3″ x 3 ” which will rest on the top of the bottom cord. the roadway that i painted black with the yollow stripes is the size if the loading block. we are testing it on tuesday.. i’ll get you some pics.

      By Dombiggers -- April 24, 2011
    • The bridge did great. It held 120lbs. (None of the joints failed). We had to use the wood provided(at best was a “b”rated).not very good wood. It was the wood that failed. So that’s $12 donation for the site.One of my class mates made a video it with his cell. when i get it, I’ll post it on you-tube and send you a link. I’m very happy. I broke the record of 80 lbs, and held more than the 100 lbs i was going for. I had alot of fun with this. I’m now thinking about doing the competitions like you do.

      By Dombiggers -- May 6, 2011
    • here’s the link to the video.
      http://www.youtube.com/watch?v=6J6EVZsnxxU

      By Dombiggers -- May 7, 2011

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