Abstract
This paper describes the hysteretic force-deflction relation for a pile foundation. It is assumed that the pile is a one degree-of-freedom systen in this investigation. The summary of thispaper following. (1) In the case that the F-y relation (force-deflection) of pile shows one straight line on a log-log paper, that is, it is represented by equation (3), the resonant frequency is obtained by equation (16). And the equiralent viscous damping constant for the equation (3) and (4) is determinad by equation (9). (2) In the case that the F-y relation (skelton curve) of pile shows two dog-leg straight line on a log-log paper, this relation is approximately represented by equation (18) and Fig. 5 (b). (3) It is recegnized that the α-value of F-y relation has changed in the result of lateral loading test for soil at various depth of loam layer. And the value of near the ground surface is lower than that of deep position (Fig. 6 (a), (d)). (4) In the above mentioned layer, snd after yielding, the α-value of RC pile whose head is free is nearly equal to the value of near the ground surface soil. But, there is no difference in the initial value of α between the two (Fig. 6 (d)). (5) The hysteretic curve for equation (18) of skelton curve is approximately shown by equation (19) and Fig. 4 (b). (6) The equivalent viscous damping constant for equation (18) and (19) is determined by equation (20). (7) Steady state sesponse curves of the one degree-of-freedom system whose hysters is loop is described by Eq. (19) is obtained by Eq. (24).
