While he was employed by the University of Illinois, Willis Slater evaluated the structural integrity of many slab concrete floor plans. His expertise on the subject even got him called into court to testify. In Turner v Lauter Piano Co. et al., he was subpoenaed by the District Court to offer his knowledge, particularly of a testing project at International Hall on the edge of the Stockyards in Chicago.
Subpoena issued to Willis Slater by T. C. MacMillian, Clerk of US District Court of Northern District of Illinois
Slater had assisted in testing the concrete floor of C. A. P. Turner’s International Hall building. The building’s floors were built with Turner’s patented ‘mushroom design’ of a single reinforced concrete floor slab supported by columns and cantilevers without any additional beam supports. Slater, along with a few other engineers tested the load capacity of the design system for approval by the Chicago Building Department.
Example of a Turner Mushroom Design Column before pouring concrete slab, Seattle, WA.
The case that Slater was called to testify in was relating to Turner’s patent for the mushroom design. The eventual decision by the Third Circuit Court of Appeals voided Turner’s mushroom design patent on the grounds that no novel idea was developed in the improvements in Turner’s design.
By Tim Morgan