Elevated Bridge B/C

[Aia]

Don't use the results at that clinic as too much of an indicator for what's possible.
Jeff Anderson
Livonia, MI

20kg is very feasible without building an excessively heavy bridge.

[andrewwski]

I'm going to really recommend the assistance of software on this event.

Where can one find such a thing?

Does your school have any engineering classes? They may have a copy of SolidWorks or something. That's really the best thing to use.

I'm just using a program called MDSolids. It's nothing wonderful but it does what I want it to.

Don't use the results at that clinic as too much of an indicator for what's possible.
Jeff Anderson
Livonia, MI

20kg is very feasible without building an excessively heavy bridge.

Yes...but what would you define as excessively heavy?

[Aia]

Sorry, I can't give any hints on that one- it would give away too much information. However, given that I've built towers and booms before, you could probably see what perspective I'm coming from.

[JimY]

A good program for calculating truss stresses is at the following website:

http://www.jhu.edu/~virtlab/bridge/truss.htm

It takes a few minutes to get the hang of it, but you quickly realize that it won't calculate anything that isn't entirely composed of triangles.

My advice is to design several trusses with the program before you start building anything. Experiment with different heights between the top and bottom chords and see how this changes the forces. Also, experiment with different truss shapes. You'll learn much about classic bridge design.

[Aia]

Has anyone else started to break bridges yet? Any thoughts on the event?

I'm testing my eighth today, yay. This event is so much better than boomilever. I don't know about anyone else, but I'm thrilled that I don't have to make bases anymore.

[andrewwski]

Heh...I can agree with that.

I haven't gotten past the design stage of any bridge yet, but I should.

What's everyone's opinions on designs? I'm leaning toward a traditional bridge on pillars...to start with anyway. Gotta start somewhere.

[dudeincolorado]

im right now designing like CRAZY i cant seem to make a design that conects the legs of the bridge to main part they right now are just two separate peices oh well.... Aia you're on your 8th bridge? Thats insane you must be getting some good scores.

[Aia]

So far, I've come up with two unique designs for bridges that seem to be working well. After all my testing, I'm guessing scores should go into the 2000 range (for C division) at least. However, it's early in the season, so this range might appear completely wrong after I test a few more. It's hard to get a feel for what scores will be like at this point in time.

[dudeincolorado]

ummmm wow though scores are up there... wow

[Aia]

Actually, I'm interested to see how the Div B scores compare to Div C. Although Div B has easier specs and should have higher efficiencies, Div C scores might be higher because some of the builders have had years and years or experience. It's tough to say.