I will keep an eye on those halogens!
I work in the construction industy, so in and out of various commercial buildings, so just copy what I see. The steel work in these buildings can be quite complicated, but observation is the key (true for other things as well of course) and important on the model to add the cross-braces etc in the vertical sections. Also there will be 'wind-braces' in the roof between the steel work, plus the roof purlins to support the roof itself - none of this is seen from normal viewing angles, so not modelled - only model was is generally seen! I've also working in engineering, so some of the details (like the pump-trucks) are also copied from what I've seen. The I-beam / H-beam sections are from the excellent Evergreen range, they are a little expensive, but very good quality and glue easily with Mek-Pak.
The next important job to do on the main building is to add the roller shutter door, which will have support brackets / bearings etc, plus the chain to open / close. I think that a motorised door (dummy of course) is not really necessary on this model, but would be relatively easir to add. I need to get this made in the next week or so.
Mudmagnet