Evaluation of seismic coefficient for gravity quay wall via centrifuge modelling

Pseudo-static approach has been conventionally applied for the design of gravity type quaywalls. In this method, the decision to select an appropriate seismic coefficient (k_h) is an important one, since k_h is a key variable for computing an equivalent pseudo-static inertia force. Nonetheless, there is no unified standard for definition of k_h. In Korea, there are conflicts between seismic design code and seismic performance evaluation code of port structures regarding the reference point of peak ground acceleration (PGA) used in determination of k_h according to the wall height. In this research, three dynamic centrifuge tests were performed for gravity walls of different heights (5 m, 10 m, 15 m) to clarify the reference point of PGA used in determination of k_h according to the wall height. The tests were carried out on reduced-scale models of gravity quay walls designed (k_h =0.13) in dry cohesionless sand. Results from dynamic centrifuge experiments showed that in cases of 5m and 10m wall, the design k_h (0.13) value is similar with half of PGA from the base of the wall. On the other hand, in case of 15m wall, the design kh value is comparable with half of PGA from the surface of backfill soil.