The ASCE 7 Tsunami Loads and Effects Design Standard

Many coastal areas in the U.S. are subject to tsunami hazard. The public safety risk has been partially mitigated through warning and preparedness of evacuation, but community disaster resilience requires that critical and essential facilities provide structural resistance to collapse. Furthermore, there are coastal communities in the states of Alaska, Washington, Oregon, California, and Hawaii where there is insufficient time for evacuation. The Tsunami Loads and Effects Subcommittee of the ASCE/SEI 7 Standards Committee has developed a new Chapter 6 - Tsunami Loads and Effects for the 2016 edition of the ASCE 7 Standard, Minimum Design Loads for Buildings and Other Structures. The ASCE 7-16 Tsunami Loads and Effects chapter will become the first national, consensus-based standard for tsunami resilience for use in the states of Alaska, Washington, Oregon, California, and Hawaii. The new ASCE 7 provisions implements a unified set of analysis and design methodologies that are consistent with probabilistic hazard analysis, tsunami physics, and structural target reliability analysis. The approach developed by the ASCE Tsunami Loads and Effects Subcommittee results in the first unification of tsunami hazard mapping for design and would reflect a modern approach of Performance-Based Engineering, in which explicit reliability targets for performance are used in the development of the design requirements. The purpose of this paper is to provide an overview of the technical basis and methodology for tsunami-resilient design of critical and essential facilities, taller building structures, and tsunami evacuation refuge structures.