Based on the example of an apartment building at a reclaimed site in coastal area near Kobe, attempt is made to investigate possible options for the seismic design of piles under the action of large lateral ground movement. The building had inclined towards sea due to lateral ground movement accompanied by the failure of quay walls during the 1995 Hyogoken-Nambu earthquake. Reports based on observations and measurements after the earthquake show that the prestressed concrete (PC) piles under southern footing had moved laterally by about 90cm, accompanying a ground settlement of about 60cm. Evidently, ground slip surface developed inclined downward towards sea at an angle of about 15 degrees, causing breakage of piles at a depth coinciding with the slip surface. Piles under footings to the north, not included in the slip surface, had failed only at the top. Simple analysis considering the load on piles equivalent to the estimated frictional resistance along the ground slip surface is undertaken. Nonlinear ground response analysis and the estimation of displacement response effect by method proposed earlier by the authors are undertaken. Finally, results of SSI analysis based on the 1-D lumped mass model are given and implications for design practice discussed.
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