SOM‘s Timber Tower Research Project applied its mainly wooden structure to a prototypical building based on an existing concrete benchmark for comparison. This benchmark building is the Dewitt-Chestnut Apartments; a 395 foot tall, 42 story building in Chicago designed by SOM and constructed in 1966. SOM’s solution to the tall wooden building problem is the “Concrete Jointed Timber Frame,” which relies on mass timber for main structural elements and supplementary reinforced concrete only at the highly stressed locations of the structure: the connecting joints.