Abstract
In the seismic design codes for railway structures, a deformation capacity of RC piles is evaluated based on the experimental results, which have been obtained from the alternate loading tests of RC columns under the atmosphere. The actual behavior of piles, however, is expected to show greater ductility than these experimental results, because piles embedded in the ground are subjected to confining pressure from the subgrade. In this study, we aimed to establish the rational evaluation method of seismic performance of pile foundations. A calculation method of ductility of RC piles is proposed, in which confinement pressure by the subgrade reaction is converted into an equivalent passive confinement pressure from circular steel hoops. By the way, we have been conducted the alternate loading tests of RC columns supported by coil springs in stead of the ground. Comparing these experimental results with those obtained from numerical simulation using proposed calculation method, the applicability of the newly developed method is confirmed. In addition, the seismic response of railway structures having general shape and size is calculated using the proposed model, and the applicability of the proposed model to railway structures is also confirmed.
