(1) Load distribution. Loads on a deep foundation are simulated by a vertical force Q and a lateral force T, Figure 3-1. These vertical and horizontal forces are considered separately and thcir individual effects are superimposed. Unusual cross sections should be converted to a circular cross section for analysis when using computer programs such as CAXPILE (WES Instruction Report K-84-4) or AXILTR.
(2) Construction influence. Construction methods, whether for driven piles or drilled shafts, influence pile capacity for vertical loads through soil disturbance and pore pressure changes.
(a) Driving resistance. A wave equation analysis shall be performed for driven piles to estimate the total driving resistance that will be encountered by the pile to assist in determining the required capability of the driving equipment.
(b) Structural capacity. Total stresses that will be generated in the deep foundation during driving or by vertical and lateral loads will be compared with the structural capacity of the foundation.
Fig. 3-1 Loading support of deep foundation.