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[enikolayev]

Finally got around to testing our paper truss since its dead week and all.

File folder bridge load test

Bridge didn't fail, ran out of time/weight. Will retest and upload a new video by Wed.

Bridge weight: 90 grams
Expected Failure load: 32lb

Load applied in video: 31lb not including wooden loading mechanism.

Taking bets on the failure load.

btw: does this qualify as fabrication?

[2point2]

65lbs..

[enikolayev]

65lbs..

A little too optimistic there i think

[speedjunky01]

not bad, my HS physics we used balsa wood, i got 180lbs and 29 grams

school record  

was cool to see the bridge explode lol

[enikolayev]

not bad, my HS physics we used balsa wood, i got 180lbs and 29 grams

school record  

was cool to see the bridge explode lol

That's an insane strength to weight ratio! how long was the span of your bridge and what glue did you use?

[speedjunky01]

not bad, my HS physics we used balsa wood, i got 180lbs and 29 grams

school record  

was cool to see the bridge explode lol

That's an insane strength to weight ratio! how long was the span of your bridge and what glue did you use?

god was forever ago. . . i think it was about 12-14" used guerrila glue, finger joints at all connections, used steam to bend the top truss, driled holes in every piece of wood that was being pulled with the grain, also sanded all off the corners off to get some more weight off. wish i had a pic of the thing.

it literaly blew up wood in a 5ft radius around it lol. the holes shaved a lot of weight off it

[t_cel_t]

fuck, i know on youtube i saw a video of some girls paper bridge holding i think 1800 lbs, hold on let me find it.

oh yeah i think it was held together with jb weld 

*edit 1071 lbs
Paper Bridge World Record - 1071 lbs

[enikolayev]

Her bridge is more like a massive frame, lol. Very impressive though.

For our project we weren't supposed to use any strengthening mechanisms. Used rubber cement to glue tubes together, and wood glue on the joints. The object was to accurately predict failure load, mode, and location. However i think we botched up some testing and the paint, which was supposed to provide a negligible strength increase, is actually giving us a pretty big boost in strength.

As you can see from the video the vertical bars on the outside of the bridge are not even taut. so i'm guessing maybe 10 more lbs...

[Corey]

how the fuck did a paper bridge hold that much weight?

[enikolayev]

15-20 layers of paper in each tube. short span. it adds up...

[t_cel_t]

yeah go grab a sheet of paper and roll it up and try pulling it apart, not going to happen

[enikolayev]

File folder bridge load test part 2

Failure at 2:28 about 36-37 lb


All of the bridges. Ours second one is on the far left. held 24 lb