Seismic Performance of Pile-Supported Wharf Structures considering Soil-Structure Interaction in Liquefied Soil

Many existing pile-supported marginal wharves within ports along the West Coast of the United States were designed in the late 1960s and early 1970s using the seismic design criteria available then, which were much less robust than the current criteria. As a result, structures designed using these criteria have often been severely damaged during the past earthquakes. This paper investigates the modal properties and vulnerability of such structures by using advanced structural and soil modeling procedures to perform two-dimensional nonlinear plane-strain seismic analyses using time histories of ground displacement and excess pore water pressures within the underlying soil embankment. Results show that the wharf structure experiences large permanent deformations and undergoes failure of the piles and pile-deck connections and pullout of batter piles in tension under large seismic events. Such failures were observed at the Port of Oakland during the 1989 Loma Prieta earthquake and also during other earthquakes throughout the world.