Abstract
To evaluate the cause of damage and damage process of still pipe pile foundation structure in a reclaimed island damaged during 1995 Hyogoken-nambu earthquake, dynamic analysis by using multi-lumped mass and spring model and static analysis by using a model of piles supported by Winkler type springs were conducted. At first superstructure was damaged by strong motion before liquefaction, and large bending moments beyond the ultimate plastic moment appeared at G.L.-6m near the water level and around G.L.-15m, the lower boundary of “Masado” caused by large deformation of ground during accumulating process of excess pore water pressure. At last, piles deformed residually due to liquefaction-induced lateral spreading of the ground towards the quay walls after liquefaction. These methods mentioned above could explain the cause and process of pile damage during the earthquake.
