zenwebb:
@DaveEvans: of course, that was the first thing I did, way before posting this topic. Trouble is, all of the literature I have found don't give any code examples or hardware implementations, only densely academic results. Most of the results I found were much more heavily interested in the mathematics of the problem, which were all totally over my head.
What you are trying to do has been done on dozens, if not hundreds, of bridges around the world. As you have found, it is not a simple problem, and it seems that more study of the mathematics of the problem (on your part) would be worthwhile.
Also, if you haven't found "the answer" in literature searches, then you'll probably get more help if you call some of the authors of the papers you have found, or talk to your state (or whatever) "department of transportation." (On similar crusades, I have found that phone calls often work better than email, but it sometimes takes persistence.)
The answers you get might depend on who you are: If you are an employee of a consulting engineering firm, then obviously other consultants will not be interested in talking to you, and the DOT will probably think YOU should be the expert coming to them with solutions, not questions. On the other hand, if you are a student, then they will be more inclined to help you.