Examples of the possible columns can be seen by clicking here . This allows the column to perform as part of the interior thermal mass and achieve a very stable temperature. This contributes for great longevity as the expansion and contraction due to temperature fluctuations that slowly but surely degrades any structural material is minimized. For example, temperature may fluctuate from -20 to 100 degrees outside over a year but this structural system would fluctuate between 58 and 72 degrees, or 120 versus 14. In preventing cracking over time, this makes a big difference.
Spandrel beams are deep beams between columns.
They contribute a lot of rigidity against horizontally applied forces like wind and earthquake. The same board that can form a column can also be laid horizontally on top of the expanded steel. That will form a beam with the board defining the bottom and the top of the roof slab being the effective beam height. This beam also gives stiffness to the roof slab allowing a thinner slab for a greater span. That is illustrated in this click also.