The American Society of Civil Engineers (ASCE) has developed tsunami-resilient design standards for the construction of buildings on the West Coast of the United States, Alaska and Hawaii.

As a part of the tsunami design criteria and methodology, ASCE collaborated with the University of Washington Joint Institute for the Study of the Atmosphere and Ocean (JISAO) and design firm AECOM to develop region-specific maps graphically depicting the potential extent of tsunami inundation. The maps reveal that nearly 3.5 million residents of the West Coast of the U.S., Alaska and Hawaii are at risk of the impacts of a tsunami.

"Rather than ignoring a hazard and suffering the consequences, tsunamis should be factored into the planning, siting, design and construction of high-risk buildings," says Gary Chock, chair of ASCE's Tsunami Loads and Effect Subcommittee. "This up-front investment produces sustainable, disaster-resilient communities that are safer and more likely to survive in the event of a tsunami. It has been shown time after time that appropriately designed multi-story buildings save lives during a tsunami, offering places of safety."

The inundation maps are included in a digital geodatabase tool to assist engineers in the design of resilient facilities and buildings to better protect communities against tsunamis. Through use of the tool, engineers will have the specific tsunami conditions to be resisted by a structure at its site.

"Probabilistic hazard and inundation maps like these help to provide the necessary information when designing structures located in areas at risk for tsunamis," says Dr. Yong Wei, research scientist with JISAO and the National Oceanic and Atmospheric Administration. "These tsunami design zone maps tell us the inundation distance and run-up elevations—key factors for calculating tsunami effects on specific structures under the ASCE standard."

In the aftermath of recent tsunamis, ASCE sent teams of engineers to various disaster areas to analyze the damage. They discovered that existing U.S. building design codes and emergency planning are not enough to spare buildings and prevent loss of life in the event of a tsunami, necessitating the development of the new standard.

ASCE will publish the new standard in ASCE-7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, and a companion guide, Tsunami Loads and Effects: Guide to the Tsunami Design Provisions of ASCE 7-16, both due to be released in early 2017.

ASCE cites Ocosta Elementary School, in Westport, Washington, as an example of how to build more resiliently using the new tsunami standard. The school, located on a peninsula on the Pacific Coast, was rebuilt with a host of features in its new gymnasium to protect the structure and serve as an evacuation refuge during a tsunami that would flood the entire peninsula. Among the tsunami-resistant features are 50-foot pilings and 14-inch-thick concrete walls for the nation's first vertical rooftop evacuation refuge structure, capable of accommodating 2,000 people who would otherwise perish.