During the 1979 Imperial Valley earthquake, an array of 26 strong-motion accelerometers produced records for the Meloland Road Overpass, a two-span reinforced concrete bridge structure located only 0.5 km away from the causative fault for this earthquake event. This paper describes the application ofa new system identification methodology to the array of strong-motion measurements, in order to assess seismic response characteristics of this bridge. Results of this application show that (1) linear models provide an excellent fit to the measured motions of the bridge, despite the fact that it was subjected to very strong shaking; (2) the transverse response of the structure is controlled by its abutment motions, with no significant dynamic amplification in the deck; and (3) the vertical response of the bridge deck at the midlength of its spans is dominated by a single vertical translational mode whereas, above the central pier, the deck's vertical response is most affected by the vertical motions of the pier base and by torsion of the deck. Also, systematic estimates of modal damping ratios and qualitative assessments of states of stress developed in the bridge during the earthquake are provided.

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The Port de Port-au-Prince is the largest seaport in Haiti, and is essential to the country's economy. The Haiti earthquake severely damaged the Port, which disrupted the transport of cargoes into Haiti that were vital to the country's emergency response and post-earthquake recovery. Major contributors to this damage were widespread soil liquefaction, the poor performance of batter piles, and the poor pre-earthquake condition of many components of the Port's waterfront structures. Immediately after the earthquake, a U.S. military task force was deployed to the port to perform emergency repairs needed to reestablish cargo throughput. These repairs restored a significant cargo-throughput capacity at this small but vital seaport within weeks after the earthquake.

Ports play a critical role in transportation infrastructure but are vulnerable to seismic hazards. Downtime and reduced throughput from seismic damage in ports results in significant business interruption losses for port stakeholders. Managing risks from systemwide disruptions resulting from earthquake damage has been studied as a central element of a project sponsored by the National Science Foundation Network for Earthquake Engineering Simulation (NEES) program. Presented are the concepts and methods developed for the seismic risk management of a portwide system of berths. The framework used to calculate port losses is discussed, particularly the use of spatially correlated ground motion intensity measures that estimate damage to pile-supported wharves and container cranes, the repair costs and downtimes subsequently determined via repair models for both types of structures, and the impact on cargo handling operations calculated via logistical models of the port system. Results, expressed in the form of loss exceedance curves, are calculated.