Paper Bridge

[josh181830]

We have to make a bridge out of paper that must hold 105 Kilograms of weight, the bridge cannot exceed 5kg. The weight will also be hung from the deck of the bridge (which is made from paper, of course). What would be the best way to make this?

 

 

 

Edit: The only materials that can go on the bridge are: normal computer paper and white glue (generic glue).

 

 

 

Edit Edit: Typo for the bridge's maximum weight, it is actually 5 kg max :oops:

[Lenticular_J]

I believe a suspension bridge is your best bet. That's all I really know to say.

 

 

 

That's a big project >_>

[Sbrideau]

Also make sure you roll the paper, much more solid that just folding it.

[Zox]

Make it like this.

 

 

 

 

 

 

 

 

Not sure, but I think that was the world's largest functional paper bridge.

[wild_goat_14]

Party and relax until the day before it is due. Then steal someone else's and hope it works.

[josh181830]

I believe a suspension bridge is your best bet. That's all I really know to say.

 

 

 

That's a big project >_>

 

 

 

Well I have been told that suspension bridge is the best, but the question is, how do I make it out of paper?

 

 

 

Also make sure you roll the paper, much more solid that just folding it.

 

 

 

Yes, I am rolling the paper to make the tube as small as possible.

[Stilev]

[hide=][/hide]

 

 

 

look up toothpick bridges since they are a much more common but similar assignment for ideas

[Tribal]

My class had to make a bridge out of popsicle sticks, and my group won by far. I stood on top of our bridge and it didn't collapse, and I'm 6'2-6'3 230-240

[Star_Fox]

reinforce the paper by putting foil and cardboards inside. that's if you have enough to support 105kg. :wall:

[thrash-boy]

heres another pic of the bridge stilev posted:

 

[hide=another pic][/hide]

 

 

 

after seeing that pic I'm also interested in building a toothpick bridge.

 

 

 

i looked further into the page where that picture was and it was designed with 4 beams that have a special curve (explained below) with struts connecting them.

 

 

 

The lower beams are tilted inwards looking at the pictures, most likely so they can push the weight coming from the struts above them into thye other lower beam, effectively canceling it out (like when 2 people with even strength pull a rope in opposite directions, the rope doesn't move. the force was canceled out by the other persons opposite force).

 

I have drawn a terribly picture in paint in a pathetic attempt to explain it:

 

[hide=basic structure]

 

Black Lines = lower beams

 

red Lines = upper beams

 

green lines = struts (diffrent shades for diffrent sides. Notice how they are placed to create a triangle formation, not straight up and down)

 

Teal (light greenly blue) lines = struts connecting 2 upper beams (to help prevent them from separating outwards away from each otherand the bridge flattening. These are the only ones that are being forced apart i think, instead of being 'squashed' or compressed)

 

Purple Arrows = the force from the upper beams holding the load going down the vertical struts into the lower beams and canceling each other out partly due to the tilt of the lower beams (not completely but partially canceling each other out. if the lower beams were directly facing each other it would fully cancel out, but they arnt)

 

 

 

PLEASE NOTE: the lower beams, although it doesn't look it, are not laying flat. ie if you measured from the ground to the lower beams at the center of the bridge, it would not be 0 (touching the ground). if you done the same at each end, they would be 0 (touching the ground)[/hide]

 

 

 

Now to explain the curve of the beams. imagine i had a peice of string and tied one end to the top of a pole, and the other end to the top of another pole which is exactly the same height (assuming this is all done on a level ground). Now imagine the length of the string is longer than the distance between the 2 poles. The string would sag in the middle towards the ground due to gravity.

 

The curve of the beams is exactly the same curve the string would have, except turned upside down (imagine gravity was the sky, the string wouldn't sag down, it would sag up towards the sky)

 

 

 

You can read more about that bridge pictured at the top of this post here. You can read about the algebra required to calculate the curve here

 

 

 

I hope i have helped. I certainly think this bridge design would be very strong, and im going to attempt to make one from toothpicks for fun.

[Sly_Wizard]

We have to make a bridge out of paper that must hold 105 Kilograms of weight, the bridge cannot exceed 105kg. The weight will also be hung from the deck of the bridge (which is made from paper, of course). What would be the best way to make this?

 

 

 

Edit: The only materials that can go on the bridge are: normal computer paper and white glue (generic glue).

 

 

 

I remember doing something like this in high school. Only it was with popsicle sticks. Ehhh... I'm not so sure how well this'd work with paper. It's too flimsy (Unless you roll/fold it as many times as possible) :|

 

 

 

But, yeah, a suspension bridge would be your best bet.

[thrash-boy]

But, yeah, a suspension bridge would be your best bet.

 

only if the bridge has to cover a long distance, otherwise a bridge like the one i posted above would probably be better.

 

a suspension bridge is still a very good bridge though.

[Ginger_Warrior]

Make it like this.

 

 

 

 

 

 

 

 

Not sure, but I think that was the world's largest functional paper bridge.

 

What happens if it rains...? :-k

[Zonorhc]

Use lots of congealed glue for support columns. Technically does not add to the bridge's weight.

[thrash-boy]

What happens if it rains...? :-k

 

 

 

you get twice as wet because you fall in the river as well

[Greatsilverwyrm]

What happens if it rains...? :-k

 

 

 

you get twice as wet because you fall in the river as well

 

 

 

That.. was genius.

[megakiller32]

This may sound incredibly ridiculous, but at my school, there was a week where most of the class went to France on a trip, and i didn't go, with some other people.

 

The work we studied while they were gone, were...Bridges. With my most hated teacher too.

 

My god. Worst school week of my life. EVER.

 

 

 

But anyway, onto the point, put tons and tons of glue on the supporting sections, to hold weight. \

[josh181830]

Still open for ideas...

[Tbfgraphx14]

Make two stacks of 100 pages of paper, put then like 5cm apart, and put 200 sheets of paper spanning it \

[Kill_Thomas9]

heres another pic of the bridge stilev posted:

 

[hide=another pic][/hide]

 

 

 

after seeing that pic I'm also interested in building a toothpick bridge.

 

 

 

i looked further into the page where that picture was and it was designed with 4 beams that have a special curve (explained below) with struts connecting them.

 

 

 

The lower beams are tilted inwards looking at the pictures, most likely so they can push the weight coming from the struts above them into thye other lower beam, effectively canceling it out (like when 2 people with even strength pull a rope in opposite directions, the rope doesn't move. the force was canceled out by the other persons opposite force).

 

I have drawn a terribly picture in paint in a pathetic attempt to explain it:

 

[hide=basic structure]

 

Black Lines = lower beams

 

red Lines = upper beams

 

green lines = struts (diffrent shades for diffrent sides. Notice how they are placed to create a triangle formation, not straight up and down)

 

Teal (light greenly blue) lines = struts connecting 2 upper beams (to help prevent them from separating outwards away from each otherand the bridge flattening. These are the only ones that are being forced apart i think, instead of being 'squashed' or compressed)

 

Purple Arrows = the force from the upper beams holding the load going down the vertical struts into the lower beams and canceling each other out partly due to the tilt of the lower beams (not completely but partially canceling each other out. if the lower beams were directly facing each other it would fully cancel out, but they arnt)

 

 

 

PLEASE NOTE: the lower beams, although it doesn't look it, are not laying flat. ie if you measured from the ground to the lower beams at the center of the bridge, it would not be 0 (touching the ground). if you done the same at each end, they would be 0 (touching the ground)[/hide]

 

 

 

Now to explain the curve of the beams. imagine i had a peice of string and tied one end to the top of a pole, and the other end to the top of another pole which is exactly the same height (assuming this is all done on a level ground). Now imagine the length of the string is longer than the distance between the 2 poles. The string would sag in the middle towards the ground due to gravity.

 

The curve of the beams is exactly the same curve the string would have, except turned upside down (imagine gravity was the sky, the string wouldn't sag down, it would sag up towards the sky)

 

 

 

You can read more about that bridge pictured at the top of this post here. You can read about the algebra required to calculate the curve here

 

 

 

I hope i have helped. I certainly think this bridge design would be very strong, and im going to attempt to make one from toothpicks for fun.

 

 

 

sorry for not contributing anything useful, but I was seriously gasping for air laughing when I saw that drawing! The bridge just looked to nice and orderly.. and then the picture... well you get the idea. And I think how you insulted your drawing is what did it. Sorry, but I was seriously in stitches.

[silver_wits]

PAPER MACHE FTW

 

 

 

make a brick of it. poke a hole through it. viola. a bridge. where water can run through. 8-)

 

 

 

any technical or physics teacher will hate you. :?

[thrash-boy]

sorry for not contributing anything useful, but I was seriously gasping for air laughing when I saw that drawing! The bridge just looked to nice and orderly.. and then the picture... well you get the idea. And I think how you insulted your drawing is what did it. Sorry, but I was seriously in stitches.

 

 

 

I'm glad you liked it :thumbsup:

[Maulmachine]

Paper+bridge= your gonna get wet

 

 

 

I bridge out of paper? That's a tall order for a hs student, how much must it hold?(sorry if I missed it)

 

 

 

I remember building one out of little sticks, we pu upwards of 300-400lbs on it, it didn't break :shock:

[thrash-boy]

how much must it hold?(sorry if I missed it)

 

 

 

according to the first post: it must hold 105kg and can be made with a maximum of 105kg of materials.

 

that's a big bridge if you ask me. maybe it was 105 grams?

[warren211]

105 kg?!?!?! I'm in the customary system so lets see thats... carry the one... type into google... thats... 220 pounds?!?!?!?!?!

 

 

 

Holy crap, that's a tall order! You gotta use a LOT of paper rolled up. I guess it's reasonable, paper rolled well enough is almost as hard as metal. But still... in 8th grade my friend had a project where he has to build a bridge out of toothpicks. The bridge simply had to outlast the other bridges in the class by holding the most weight. I think he managed a few dozen grams, but still... 220 pounds/105 kilos? The weight of a muscular teenager? Bring out the super glue, elmer's won't cut it.