SYMPOSIA PAPER Published: 01 January 1979

Influence of Driving Stresses on the Development of High Pile Capacities


The impact stresses have been measured near the top of piles as they are driven to practical refusal in very dense granular soils and shale bedrock. These stresses have been compared with capacities determined from static load tests. The comparisons were carried out on 24 piles of various types and lengths driven with a wide range of hammers and capblocks at different sites. They indicate that the ultimate bearing load divided by the pile shaft cross-sectional area during driving averages 1.2 times the impact stress at practical refusal with a standard deviation of ±20 percent. This is in close agreement with the Case method wave equation analysis. It is concluded that, for conditions similar to those tested, driving criteria to establish a required bearing load may be estimated from impact stress measurements at the top of the pile. Other methods, such as conventional dynamic formulas, are not as suitable, as they cannot measure the effects of hammer and cap block variations.

Author Information

Thompson, CD
The Trow Group Ltd., Rexdale, Ontario, Canada
Thompson, DE
Oshawa Office, The Trow Group Ltd., Oshawa, Ontario, Canada
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Developed by Committee: D18
Pages: 562–577
DOI: 10.1520/STP33752S
ISBN-EB: 978-0-8031-4740-9
ISBN-13: 978-0-8031-0291-0