Numerical Simulation and Seismic Fragility and Risk Analysis of Wharves in Liquefiable Soils
Earthquakes pose a significant threat to many large U.S. seaports which serve as critical gateways for national and international trade. Considering the fact that disruption in port activities may lead to significant direct and indirect losses, seismic performance evaluation and retrofit of ports is quite essential. Current engineering practice for seismic risk reduction for port facilities is typically based on design or retrofit criteria for individual components expressed in terms of arbitrary levels of force and/or displacement. Seismic risk analysis on the other hand provides a framework through which both economic issues and system performance can be taken into account and the performance of the port can be seen as a whole. The aim of this research is developing various elements involved in seismic risk analysis of pile supported wharves. Following tasks are accomplished throughout this research.
- Three-dimensional dynamic response of soil-foundation-wharf systems during seismic events is investigated using advanced numerical models including novel dynamic macroelements for nonlinear soil-pile interactions in liquefiable soils, force-based beam-column elements for piles, and experimentally calibrated nonlinear joint models for pile-deck connections.
- Various critical behaviors of wharves are investigated such as pile and pile-deck connection failure mechanisms, permanent deformations of potentially liquefiable soil embankments, and effects of far-field and impulsive near-field ground motions on the torsional response of the wharves.
- The specific effects of wharf-crane interactions on seismic behavior of wharves and cranes are investigated by incorporating an enhanced nonlinear sliding/uplift capable model of a jumbo container crane into the nonlinear wharf-foundation system model. The main conclusion of this study is that in contrary to the assumption in former studies, the contribution of the wharf-crane interaction on the total seismic response of the wharf can be significant.
- A general probabilistic framework for correlated repair cost and downtime estimation of geo-structures exposed to seismic hazards is developed. The formulation of the repair cost and downtime accounts for the uncertainties associated with damage states and the reduction in the repair requirements as the number of damaged components in the given damage state increases.