Development of Nonpneumatic Caisson Engineering

The open well method of manually digging foundations down to bedrock and filling the resulting shaft with concrete or stone was developed in Chicago in the 1890s. Mechanical driling was also used at this time, a large steam-powered auger being used in Kansis City; but it was not rapidly adopted due to the cheapness of the open well process. In the 1920s, well-drilling techniques were adopted, enabling foundation piers to be drilled into soft ground to greater depths than were previously possible. Subsequently engine-driven augers were used and in 1926 a hydraulic rotary drilling method was patented by Powell and a dry method by Hunt and Ropp. These two processes were widely implemented. Mobile augers, both truck mounted and crane mounted were also developed and used. Recent developments to advance pier drilling techniques include the Benoto Deep Caisson Excavator (1957) and the use of bentonite when drilling in water-bearing soils.