Bridge Building Project

[jkv6391]

Here's a little challenge:

You need to build a bridge to fill a 40-cm gap. The bridge must be able to support 1kg for 10 seconds and flex no more than 2.5 cm. Your budget is $95 million.

Materials given are 18-cm straws at $1m, 18-cm toothpicks at 18-cm each at $5m, 6-cm toothpicks at $20m for 360 a package, 33 meters of
tape at $30m, 1 meter of string at $5m.

 

[Danger]

This sounds like a class project to me. What are your thoughts on it? Any preliminary sketches or calculations?

 

[jkv6391]

Yeah. It's a class project.
Right now my group has the most efficient design in the room. The design is painfully simple but the part that's done right now can carry about 2.5kg. I'm just looking for ideas about something a bit... cooler.

The design is like... the entire bridge is made up of three segments , each are 18 cm each. The 18-cm sticks are wrapped in tape to prevent it all from falling apart if they break. the 6-cm toothpicks are all aligned in a row one layer thick; It's all held together by tape on the top and bottom. We might add extra rigidity to the bottom by putting an isometric pattern on it. So far there is about $30m left in the budget.

 

[wolram]

You do not mention if your bridge has to be a practical means of conveying
things from a to b, a simple A frame could be a bridge.

 

[jkv6391]

No, the bridge serves no practical purpose. It only needs to be able to hold 1kg at the center.

 

[Danger]

I'm just looking for ideas about something a bit... cooler.

In engineering, 'cool' is meeting or exceeding the specified parameters on time and on budget. Cooler is doing it ahead of time and under budget. If aesthetics are part of the requirements, then by all means make it look nice. If not, spending extra to dress it up is a waste of time and money.

 

[jkv6391]

Extra points will be awarded for the most creative design, however they are not awarded if it goes over budget.

 

[Danger]

In that case, it's pretty much up to your imagination along with the basic engineering principles. To me, that's pretty much architecture. By 'creative' design, do they mean 'peculiar' or 'artistic'?

 

[civil_dude]

Since you can use string, perhaps a suspension bridge of some sort would be "cool". But you would need end conditions that would allow it.