Thank You both for your comments. I am in Pennsylvania. I am also thinking its a "homemade" device. The Architect and contractor have used it and claim other Engineers they know have used it over the years. Probably some local Engineer(maybe now deceased) had it fabricated and made the chart...
Has anyone ever heard of the "Neese" Bar used for determining soil bearing? It is a 1" steel rod that has a steel flange welded to the rod about half way up the rod. A steel weight (steel cylinder with hole in it) that weighs 25 lb. is dropped from 3 ft above the flange. The weight is hand...
