Improving efficiency by mass transportation in maritime transport of containerized and bulk cargo in recent years, economical development of port facilities such as wharves and waterways of deep water are required due to increasing size of vessels. The authors developed “a hybrid gravity-type pier” as a new quay structure, aiming at the economical establishment of deep water wharf. A hybrid gravity-type pier is composed of a deck slab, a superstructure, and columns connecting them and installed on a rubble mound. It have the characteristics of gravity type quay wall which resists earth pressure and seismic inertia force because of the weight of the pier structure and the rubble mound on the deck slab.
　Design procedure and typical construction method of the hybrid gravity-type pier are outlined in this report. Seismic performance of two types of structure was compared in a series of model test with an underwater shake table; it is clarified that a hybrid gravity-type pier without retaining wall at the front of a deck slab has higher seismic performance than with retaining wall. It was confirmed that effective stress finite element analysis (FLIP) is applicable to seismic performance verification of a hybrid gravity-type pier, reproducing the results of the model test. Results of the model test and analysis revealed that gantry cranes are possible to be installed on the hybrid gravity- type piers.