RE:Re: Vierendeel Truss Deflection
You can calculate the I value of a standard truss using Ad^2/2 and calculate deflection as normal.
This however does not apply to Vierendeel girders. So when I was prepraring for the exam I did this check numerous times for different loading types (as if it were a standard truss) and calculated more accurate deflections for the vierendeel on a software package (not during the exam!). This gave me a good idea of a suitable multiplication factor which I could quickly apply in the exam.
So for the exam you can do the standard check and multiply your answer by say 10 or 12 (depending on your research)... This at least lets the examiner know that you're aware that a vierendeel will deflect more than an ordinary truss. That's what they're looking for - not precise answers down to the mm!
I advise you to stay away from vierendeel girders in your "preferred scheme" for part 2. My advice - K.I.S.S - Keep It Simple, Stupid! :-)
Hope that helps.