I firstly want to congratulate the winners of the comp. VERY well done =)
Anyway, I wanted to know how the #### you got single beam of steel going up under the bridge?
Instead of the normal 2/square shape...
Umm, not good at explaining it...
You need to be in complex mode (there's an option at the top of the edit screen). Use F and R keys to move the editing plane backwards and forwards, and you can make those triangular beam sections. I think that's what you mean

Hope this helps.