Balsa Wood Bridge: 202 Pounds 

After unloading the platform and reloading it you had already stressed the wood. So it probably could have held more

The success of this loading was due to the fact that the suspension point was right on top of the bridge where the joints were in compression and the only tensioned joints were the horizontal lowest part. If the suspension point was on the lower horizontal part so that it was pulling rather than pushing on the bridge, this bridge would have failed before. Students should consider carefully whether to load the bridge by pushing on it at the highest points or pulling on it from the lowest point as it does make a difference.

I few weeks ago in my PLTW high school engineering class I made a truss out of balsam wood that weighed .0088 grams and held 350 lbs.

This is so amazing! :o

That was amazing! xD

Bridge efficiency is 1,078... That's Pretty good, but I hear some balsa bridges in Science Olympiad last year got scores of 1,500 to 3,400 (!). My bet is you could have held a lot more weight if you were using sand (thus gradually adding weight) instead of heavy Dumbbells. Still, that was wayyyyy cool, thanks for sharing!

You can't just put weights anywhere like they did. That's not an accurate test. Bridges aren't designed or intended to have mass load on top of the truss like that. The criteria should have been laid out from the beginning so the design could take into account where loads would be placed.

The issue of this bridge is that the load is in upper side of the bridge which means it can take more than usual bridge construction. So if you normally put loads where they use to be, on drive way, I think you will have max one third of your result.

I did this in middle school! Ohhh I want to make balsa wood bridge again!!

that is amazing. just wow

We made a balsa wood bridge in school. Ours weighed 16 grams and held 960 pounds. This bridge looks alot cooler than ours did.

amazing architecture.

My popsicle stick bridge in middle school weighed 146 grams (0.32 lbs) and used 98 popsicle sticks. It was held by just normal Elmer's School Glue. It held 200 pounds for 5 minutes and didn't break. It was tested 3 times and got over 200 lbs each time, but we didn't have any more weights so we had to call it at 200. (We stacked 50 textbooks which each weighed exactly 4 lbs so that was 200 lbs.) It had a span length of 457.2 millimeters (18 inches) and had 76.2 millimeters (3 inches) of the bridge resting on the test tables on each side.

That is frickin awesome

5:39 was the best part :D

What was the overall length of the bridge?

Awesome

Did the bridge have the requirement that no two touching pieces could be parallel?

Very nice What was the balsa wood specifications n size Surely the fiber stress was below critical Great project though !

how long do u take to make this bridge?

what size of that balsa wood?

Any details on the dimension?

daniel . is it possible you could give me the blueprints to how you did this? or where you got it from ? this could be our best bet of winning our competion for school

if the wight is not on the expansion then it's not a very good bridge test.

that was amazing! how did you guys build that?

the bridge i made held up till 467 lb total weight of bridge was 170 grams efficiency 2457.9

wats the name of the song at the end

Not bad, I expected a truss that big would take a larger load honestly.

I just made a similar one that i tested today! I have the school record at 435 lbs

What was the overall efficiency score?

My bridge held 55 punds balsa wood 3/32x3/32 squar root wood with 10 inches long 6 inches heigh and 3 inches with and it weight 4.2 grams

Ok so can you make an open file in the program ModelSmart3D pls like in 2 to10 Days

the teacher took photos and video. I'll probably upload it when I get it. The bridge had much different dimensions though. it was 10.5"x4"x3.5"

Prosta klasss

"what was that" lol

when the load impose at the top the member of compression and tension difference figure already that not exact correct way to impose the load to this test.

I have to make a finished balsa wood bridge by January 24 for science Olympiad with an eighth grader

What type of bridge design did you use? I’m making a bridge for my science class and want to hold a lot of wait:)

i put thick cement and it held a ton :P

光考虑承载力和自重没有意义，还需要考虑宽度限制，高度限制，动载还是静载。我的1.2m长，10cm宽，10cm高，能承受至少40kg静载，5kg的边载（同时支座有175Hz的1cm振幅震动）荷载不会掉下去。自重186g It is no sence only consider the resistence and selfweight, width limit, height limit, dynamic load or static load also make influnce . mine is 1.2m long, 10cm wide, 10cm high, can hold at least 40kg static load, 5kg dynamic load (while the bearing has a 1cm amplitude vibration175Hz)and load will not fall off . weight 186g

1 kg = ~2.2 pounds. So 202/2.2= 91.8, about 91.8 kg, Meaning it was able to support about 1080 times its own weight.

I built one that weighed point 88 oz. And held 450lbs

It holds 5 pounds I’m happy... 5 seconds latter ITS HOLDING MORE THAN 9000 POUNDS

this is very hard to lift

nuts'

cool to bad I don't have enough time in my class to do that

Im not the only one who realizes they were at 95lbs going 5 additional lbs at a time, why they didnt just go for 3 25lbs weights and then add another.. wouldve followed or at least picked up the progression better...

U just wanna see it break!

it held 202 pounds.

Kinda defeats the whole purpose of a "bridge" when there is a giant column in the center (eye bolt) .. Can't use the bridge if the road is blocked!

There is no way that only weighed 85 g

Hackers...

I live being a virgin

and im 13

you spelled my name wrong its Cris not Chris

1 dab 0n th3 h8rz. H0w ab0ut y0u?