Performance of Port and Harbor Structures Impacted by the March 11, 2011 Great Tohoku Earthquake & Tsunami

On March 11, 2011 the largest earthquake ever recorded in Japan struck off the coast of the Tohoku region of the country, immediately followed by the one of the largest tsunamis ever recorded. Following these devastating events the American Society of Civil Engineers (ASCE) and its Coasts, Oceans, Ports, and Rivers Institute (COPRI) committed to send multiple teams to Japan to investigate the performance of port and coastal structures. This paper summarizes the findings of the northern Port and Harbor team, whose final report is in publication and expected to be released in 2013. The northern team investigated over 14 major port facilities along approximately 300 km of coastline. The team visited Japan in May 2011, focusing on sites north of Fukushima. The COPRI team partnered with the Japanese Ports and Airport Research Institute (PARI) and greatly benefitted from collaboration with PARI port specialists in the field. While on site, the team documented observable damage and met with facility personnel, eyewitnesses, researchers, and government officials. This paper includes a brief summary of findings as well as recommendations appropriate for the ports community.

The primary purpose of the team was to assess and learn from the performance of port infrastructure including waterfront, storage, protective structures, handling equipment, process systems, and utilities. This investigation focused on the design, construction, and performance, with an emphasis on the lessons learned from both failures and successes. Topics addressed include structural performance, code efficacy, ancillary equipment performance, tsunami prediction and life safety, early warning systems, as well as recommendations for high tsunami risk ports and future research, all of which are directly applicable to US facilities.

Generally, port and harbor structures were found to have performed well, with few catastrophic failures observed. Pile supported and gravity wall structures generally performed with minimal damage. However, damage to electrical supply systems and damaged / lost equipment associated with tsunami inundation delayed restoration of full operations for many port facilities in the region. Significant loss of life was found to occur where predicted / design inundations provided vertical evacuation or seawall protection heights that were not sufficient.

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