Bridge Design Contest 2015

It looks like I won’t be playing with the bridge-design contest software this year.  I downloaded the software from https://bridgecontest.org/resources/download/, but was unable to run it.  They’ve made their software so that it only runs on Mac OS 10.7.3 or newer, but my MacBook Pro is running OS 10.6.8.  I suspect that there are a lot of schools out there running old Mac software also, so making the software run only on the new Macs is cutting out a lot of users (particularly in the less-wealthy school districts).  This is a common problem with software developers—because they invest in the latest hardware and software, they assume that everyone else is able and willing to do so.  More likely, they don’t even think about the number of people they cut out by writing programs that only run on recent computers, nor who those people are.

Note: there is a newer iMac in the household, and now that my son is in college I can get time on it, so I might install the bridge-design software there.

I know that I could also upgrade my 10.6.8 Mac (possibly even for free still), but I’ve heard from a number of students who did the upgrade last year or the year before, that the resulting laptop was far less reliable and much of their older software was broken by the “upgrade”.  I’m not willing to have to replace large swaths of my functioning software just to play one game. I’ll put up with the pain of major changes to the operating system the next time I replace the hardware.

Related articles

• West Point Bridge Designer 2011
• West Point Bridge Design Contest 2012
• West Point Bridge Design Contest 2012, again
• West Point Bridge Design Contest 2013
• Engineering Encounters Bridge Design Contest 2014

Engineering Encounters Bridge Design Contest 2014

Last year’s bridge design did not work well for the 2014 Engineering Encounters Bridge Design Contest (formerly the West Point Bridge Design Contest):

Bridge design costing about $169.9k in the 2013 contest.

When I tried a similar design in the West Point Bridge Designer 2014, I couldn’t get the cost below about $172k, but a simpler design was cheaper:

$167.3k bridge design for West Point Bridge Designer 2014.

This design is currently 12 of 41 in the open contest, so clearly one can do better. I don’t expect it to stay high on the leaderboard for long.  It would already be much worse than that on the consolidated board, since the top 10 on the open board only fall in the top 50 on the consolidated one.

I think that the contest would be more interesting to me if they had provided an API for testing bridges.  Then the challenge would be to write bridge optimization software that explored the design space much more thoroughly and tweaked the designs.  It might be possible to do that this year, as the source code is available from sourceforge.  I’m not interested enough in the optimization problem to try to interface to their Java code, but it might be a good way to make a college-level version of the Bridge Designer Contest.

Related articles

• West Point Bridge Designer 2011 (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2012 (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2012, again (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2013 (gasstationwithoutpumps.wordpress.com)

West Point Bridge Design Contest 2013

I modified last year’s bridge to meet the constraints of this year’s West Point Bridge Design Challenge:

Bridge design costing about $169.9k in the 2013 contest. Note: I’ve deliberately distorted the picture to make it difficult to blindly copy the design, as I had problems with middle-school students using my published designs to cheat on their homework. The truss design I have here can be used as inspiration, but not copied directly.
As of 2013 Jan 16, this design is number 3 in the “open competition”, but I’m sure it will slip a long way, as I don’t plan to do much (if any) tweaking.

I found it interesting that from this year’s version of the code they removed the options to change the viewpoint from which the bridge was viewed, though the included help system still describes the now-missing controls.

Related articles

• West Point Bridge Designer 2011 (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2012 (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2012, again (gasstationwithoutpumps.wordpress.com)

West Point Bridge Design Contest 2012, again

I revisited the West Point Bridge Design Contest today, and submitted a tiny modification of my previous design (not the one pictured in West Point Bridge Design Contest 2012, but the one I mentioned in the comments).

This design is currently 73rd of 1095 in the open listing, but does not look much like any of the standard templates.  It is rather “fragile” in the sense that moving any of the joints causes it to fail.

Bridge design costing about $157.6k in WPBD2012.

Related articles

• West Point Bridge Designer 2011 (gasstationwithoutpumps.wordpress.com)
• West Point Bridge Design Contest 2012 (gasstationwithoutpumps.wordpress.com)

West Point Bridge Design Contest 2012

I was wondering why my old post West Point Bridge Designer 2011 was getting so many hits recently, all from searches.  Then it occurred to me that the 2012 contest must have been released at West Point Bridge Design Contest.

I think that kids who have been assigned to do the contest are looking for ways to cheat by copying someone else’s design. Although the contest has changed the design parameters and cost functions somewhat this year, a good solution to last year’s design is also similar to  a pretty good solution for this year’s.  They’d have to change the cost functions a lot to make a different design be much better, but they are trying to stick fairly close to standard engineering practices.  I don’t believe their cost functions, though, as no one around here is able to make a 2-lane bridge capable of carrying trucks for only $166k, which is about what the cheapest design I came up with costs.  I think that they left out the cost of installing the bridge, and may be using prices from the 1960s for materials, as I doubt that a bridge can be built in California for under $2million, and big bridges cost in the billions.  Perhaps they need to scale their costs by 100.  Their site prep costs look like they are just pushing around dirt, not blasting out rocky cliffs and building piers and abutments—and even then they are way low.

In my playing around today I came up with a slightly different design from last year, probably because the width or depth is slightly different in this year’s problem:

A bridge that costs under $166,000 in West Point Bridge Designer 2012.

Although the bridge design program is fun to play with (as addicting as many other computer games), it doesn’t really teach much engineering. I did not learn the pricing model nor much about bridge construction by playing with it—just tried things randomly and scaled up beams that failed and scaled down beams that didn’t. (Well, there was a little more to it than that, but it was more gaming tricks than engineering.) I suspect that a completely stupid algorithm (like simulated annealing or genetic programming) could do a decent job of optimizing a design, particularly if you start with the templates provided.

Because my design is not very different from one of the provided templates, I don’t feel that I’m giving much away by showing this design.  (There are undoubtedly better designs out there, but I’ve spent as much time on this computer game as I can afford to waste.)

Related articles

• West Point Bridge Designer 2011 (gasstationwithoutpumps.wordpress.com)