Ung Jin Na

Simulation-based seismic loss estimation of seaport transportation system

Abstract Seaport transportation system is one of the major lifeline systems in modern society and its reliable operation is crucial for the well-being of the public. However, past experiences showed that earthquake damage to port components can severely disrupt terminal operation, and thus negatively impact on the regional economy. The main purpose of this study is to provide a methodology for estimating the effects of the earthquake on the performance of the operation system of a container terminal in seaports. To evaluate the economic loss of damaged system, an analytical framework is developed by integrating simulation models for terminal operation and fragility curves of port components in the context of seismic risk analysis. For this purpose, computerized simulation model is developed and verified with actual terminal operation records. Based on the analytical procedure to assess the seismic performance of the terminal, system fragility curves are also developed. This simulation-based loss estimation methodology can be used not only for estimating the seismically induced revenue loss but also serve as a decision-making tool to select specific seismic retrofit technique on the basis of benefit–cost analysis.

Performance Evaluation of Pile-Supported Wharf under Seismic Loading

Past earthquakes have demonstrated that port facilities suffer extensive seismically induced damage due to poor foundation and backfill soil that are common in waterfront environments. Focusing on pile-supported wharves, this study evaluates seismic behavior of port structures recognizing that most of the parameters controlling the properties of soil are of a random nature. The response of such structures inherently presents a complex soil-structure interaction (SSI) problem involving ground shaking, pile-failure mechanism, and liquefaction and lateral spreading in backfill and sand layers. In this study, using a representative model of a typical pile-supported wharf in the west coast of United States and considering an ensemble of ground motions with different hazard levels, effect of soil parameter uncertainty on seismic response is evaluated. For numerical simulations, an effective stress analysis method has been utilized. In order to investigate the effect of soil parameter uncertainty on seismic response, random samples are generated using Latin Hypercube Sampling and nonlinear time history analysis is carried out repeatedly for each realized sample. Finally, the effect of parameter uncertainty is demonstrated in terms of seismic fragility curves. The results of this study can be utilized to evaluate the seismic vulnerability of similar pile supported wharves.

Seismic Performance Evaluation of Container Cranes

For a port facility to maintain serviceability after an earthquake, individual port structures must maintain serviceability. Past earthquakes have demonstrated that important port structures such as quay wall and container cranes are highly vulnerable to damage during strong earthquakes. This paper focuses on seismic performance evaluation of a typical container crane located on a quay wall. At first, a representative numerical model of a typical gravity-type quay wall is developed and considering a large number of scenario earthquakes with various hazard levels, nonlinear time history analysis is performed assuming the ground motions to be known at the bedrock level. After that using a numerical model of a typical container crane, time history analysis is performed using the motion obtained at the base level of the crane (i.e., top of the quay wall). To assess seismic performance of the crane in the framework of performance-based design, the damage criteria for the crane are established based on the post-earthquake serviceability. Finally, seismic performance of the crane is evaluated in terms of fragility curves.