SYMPOSIA PAPER Published: 01 January 1955

Part II—Analysis of Pressure Deflection, Moment, and Shear by the Method of Difference Equations


Part II utilizes the earth-pressure and pile-deflection data contained in Part I to show the effect of different variables, particularly the parameters, k and n, on the magnitude of the maximum bending moment in the pile and the depth at which it occurs. This part also outlines applications of the data and their analyses in engineering design and presents a concise system for defining the expressions used in the method of differences as applied to the problems. The data presented in Part I are used in Part II for computing moments and shears along the embedded pile length and to evaluate the separate variables, stiffness factor of pile, width of pile pushed against soil, the height of thrust above the ground line and the parameters, k and n, with respect to their effects on earth pressures, pile deflections, and shears and moments at all depths of pile embedment. The following conclusions are restricted to the conditions of tests as described in Part I: (1) There is good agreement between the measured and theoretical earth pressures and pile deflections. (2) The most realistic earth-pressure-distribution curves are obtained with n values that are between zero and unity. (3) Laboratory tests have thus far not been adequate for determining suitable values for k and n. Those values can be determined from lateral load tests. (4) The variables, stiffness factor, height of thrust above grade, width of pile, and depth of pile embedment, have surprisingly small effects on the magnitude of the maximum moment and its location in the pile. (5) The magnitude of the maximum bending moment is much less than usually supposed and as usually computed. (6) The depth below grade of the maximum moment is much less than is commonly supposed. (7) The magnitude of the peak earth pressure far exceeds the passive earth pressure as computed from classical earth pressure theories.

Author Information

Palmer, L., A.
Bureau of Yards and Docks, Washington, D. C.
Brown, P., P.
Bureau of Yards and Docks, Washington, D. C.
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Developed by Committee: D18
Pages: 22–44
DOI: 10.1520/STP47735S
ISBN-EB: 978-0-8031-6924-1
ISBN-13: 978-0-8031-6666-0