Im a new user to Revit Structure 2012 and just drawn up my gridl ines. ive then tried to insert a column but realised Revit only lists 4 or 5 avaliable columns to put onto my gridlines. is there a way to have more columns avaliable to use?
you will need to load the families into your project.
From the Insert Tab, Load from Library Panel, choose "Load Family"
Browse to your column family. Even if you already have that family loaded into your project, you obviously don't have all the "types" of that family loaded; this keeps your project to a reasonable, workable size. You can pick and choose all the "types" (or sizes) of the family that you prefer by holding the <ctrl> key and choosing the sizes you wish to add to your project.
Depending on the columns you need in your project, you may need to do this for all of your Steel columns; each shape will require you to Load Family (i.e. you won't be able to load 5 different W-shapes and 2 HSS shapes in one Load Family session. You will need to load W-shapes in one session and HSS shapes in a separate one.)
You can always go back and add more types if you don't get them all in the first Load Family session, but try to get most that you think you'll need. It can get tiresome adding only one type at a time and having to repeat the exercise for all your columns.
... Same with beams. And different sizes of detail components like Angles, etc.