wooden bridges broken..well, not one or two

[vash]

dang that was fun. well, fun is relative but we were "working".

most of us had our student interns work on the bridges. us adults had to work (green font)

they were crazily put together. w some you could still smell the glue.

nothing took less than 100lbs. one crossed into 300. it was sick. it looked feeble, but it held.

mine? janky looking, but strong. "Lennie" was unbreakable. the hardware used to pull on the bridges failed first. hahah..

one standout. a young engineer told her son about out contest and he wanted to help. the two of them built a bridge that was epic. something DiVinci would have built with Di-Jr. she wouldn't let take it to failure. it got to 150lbs and she waved us off. haha..this engineer is still on probation and will go far. !!

pics next

[vash]

DiVinci




Broken hardware




My bridge goes airborne!

[masraum]

Awesome, thanks for the pics!

[Scott Douglas]

That's cool Cliff.
What were the parameters of the project again?
Materials used?

I'd like to build a DiVinci model for my train set.
Thanks for the pics.
Any more of the DiVinci would be appreciated.

[mjohnson]

Did anyone else do this as a kid?

I sure did - Science Olympiad! You had to span ~300mm and hold up to a bucket of sand, or about 65-70#. Your score was a mass ratio of load/bridge.

Back in 1989, besides being a star mathalite, I dabbled in the civil engineering.


20.8 grams, maxed the bucket for maybe 1500ish points. Took second in my region.

Only second among fellow ninth graders in our small town but still - weighed less than an ounce and held over 69 pounds.



I vaguely recall that in the early '90s, besides the super awesome concrete canoe, our uni's civil engineering department had a big steel bridge comp. I think it was a thing for the big civil engineering national body (like ASME but a little less dynamic). They were far larger than middle-schoolers, I think they were ~15' spans with kilopound loads. Failures were far louder than my puny balsa bridge...

[mjohnson]

Originally Posted by Scott Douglas

That's cool Cliff.
What were the parameters of the project again?
Materials used?

I'd like to build a DiVinci model for my train set.
Thanks for the pics.
Any more of the DiVinci would be appreciated.

The DiVinci bridge is soooooo on our backyard list. Perhaps ahead of the trebuchet.

We have a 12yo daughter to inspire to nerdliness!

[Seahawk]

Cliff, what a great thread.

I am, charitably, the Sybil in Civil engineering...

But I love this game: Bridge Constructor.

Do a search.

Again, this is so cool.

[herr_oberst]

This design study is a cat-sized bridge for an indoor-only cat to have unlimited, safe access from the house to the outdoor catio.

(I'm no longer dating the woman who inspired the concept, but I saved the model. I knew there was a reason and this thread is that reason)

[herr_oberst]

(I love that "DaVinci" bridge. Someone has an eerily good grasp of structure.)

[TimT]

I'm wondering which intern engineer specced the hardware for the test mechanism?

The eye bolt looks like the wimpmaster 1000 grade steel from Ace Hardware..

The class I was in did the concrete canoes and failed miserably...

[vash]

Originally Posted by TimT

The eye bolt looks like the wimpmaster 1000 grade steel from Ace Hardware..

...

hahah..it was a last minute addition. it was from ACE. hahahha...we never expected such heavy loads. last time we did this..we never crossed 100lbs.

this time we had way more time, and better glue.

true story.. we read the specs of the hardware and collectively groaned. we knew we were going to do things unexpected.