Compiled by Bogireddy Chandra:
Outline:
First Idea : 1902 : Colonel Charles R. How
Second step : 1920 : Harry Mohr (Standardized)
Third stage : 1940 : Juul Hvorslev ( Pretty much Standardized)
Finally : 1948 : Terzaghi (Recommended and published)
46 years journey of research
(Meanwhile we are Indians struggling for Freedom: 1857-1947)
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Overview on historical development of the Standard Penetration Test (SPT) with reference.
1902: Colonel Charles R. How of the United States Army Corps of Engineers proposed a method for measuring the resistance of soil to penetration using a steel rod with a calibrated tip. This idea was not widely adopted at the time.
1920: Harry Mohr, a geologist and engineer, developed a modified version of How's method that involved using a standard weight dropped from a fixed height to drive the steel rod into the soil. Mohr's method became widely used in the United States and was the basis for the Standard Penetration Test.
1940: Juul Hvorslev, a Danish engineer, further refined and standardized the SPT method. He developed a standard sampler and hammer weight, and recommended specific procedures for driving the sampler into the soil.
1948: Karl Terzaghi, a renowned geotechnical engineer, recommended the use of the SPT and published guidelines for its use in soil investigations. Terzaghi's recommendations helped to establish the SPT as a widely accepted and standardized test method for soil investigation.
Over the course of 46 years, the Standard Penetration Test evolved from an idea proposed by Colonel How into a widely used and standardized method for measuring soil strength and properties. It is interesting to note that this development occurred during a period of significant political and social change in India, as it struggled for independence from British colonial rule.
(Feel free to suggest if needs any modifications)