Burnham and Root, Frank Lloyd Wright | 1888 | Visitor Information
The Rookery was an engineering marvel at its inception, and architect John Wellborn Root’s brilliance is exemplified in the foundation and structure. Root developed a means for dispersing the vertical weight of the structural columns onto a horizontal plane that “floated” on Chicago’s soggy soil. Specifically, he devised a “grillage foundation”—iron rails laid in a crisscross pattern and encased in concrete that supported the building’s immense weight. [paragraph break] The steel frame skyscraper had not yet been perfected. Thus, Root designed a hybrid structure of masonry exterior walls and steel and iron interior supports. The light court is a system of iron beams and channels that are independent of the exterior walls. Root even took into consideration that the masonry walls would settle at a different rate than the steel portions.
Information provided in part by: The Rookery