The proportions of the Railway Exchange's Piazza/Lightwell/Doughnut (see previous post) are determined by the engineered length of each steel span. And because steel is capable of spanning much longer distances than stone (the Classic building material) the emphasis of this new (new to the turn-of-the-century) steel frame architecture tends to be horizontal rather than vertical. This was a dramatic visual shift. The first impression to the early twentieth century eye, would be that this thing couldn't possibly stand up.
Steel columns were covered in terra cotta, simulating columns of a more familiar thickness. Beams were also fleshed out to similar, more comfortable proportions -- creating a hybrid vision of "new" and "old."
FOR MORE CHICAGO ARCHITECTURE, SCULPTURE AND PHOTOGRAPHY begin with
THE CHICAGO LOOP