The American Society of Civil Engineers is preparing to publish the world’s first standard for the design of critical structures to resist the impact of tsunamis. The document, which includes interactive digital inundation maps, is intended to serve as a model for the creation of standards in vulnerable coastal areas around the globe.
“In the U.S., tsunami hazard has not been considered at all,” said Gary Chock, president of Martin & Chock Inc. and chair of ASCE’s tsunami loads and effects subcommittee, at the ASCE 2016 Convention, held Sept. 28 to Oct. 1 in Portland, Ore. “We have filled the gap by providing a means of improving community resilience for critical infrastructure.”
乔克长期以来一直坚持认为，海啸应纳入高危沿海建筑的规划，设计，设计和建设。他说：“现在，我希望全球各地的社区也将从ASCE的工作中受益，并使用这种方法开发自己的地图。”
开创性的努力包括为华盛顿州，俄勒冈州，加利福尼亚州，夏威夷和阿拉斯加的海啸沿海地区创建数字互动式淹没图。根据ASCE的说法，这些地图显示，将近350万居民处于危险之中。
For the maps, which graphically depict the extent of tsunami inundation in specific regions of the U.S.—including those proximal to the Pacific Ocean’s earthquake-vulnerable Cascadia Subduction Zone—ASCE collaborated with the University of Washington’s Joint Institute for the Study of the Atmosphere and Ocean (JISAO) and AECOM.
Calculating Effects
The tsunami design zone maps—part of the new ASCE Geodatabase-Version 2016-1.0—tell engineers the inundation distance and run-up elevation factors for calculating tsunami effects on specific structures, said Yong Wei, a JISAO research scientist and a tsunami loads and effects subcommittee member.
海啸设计规定在850名注册人的大会上首次亮相，计划于明年年初作为“ ASCE 7-16：建筑物和其他结构的最低设计负载和相关标准”的第六章出版。
新的一章包括份42页的标准60 pages of commentary. It was approved by the structural committee of the International Code Council for inclusion as a reference document in the model 2018 International Building Code (IBC), subject to confirmation at the ICC final action hearing later this month.
However, the National Association of Home Builders and the Asphalt Roofing Manufacturers Association are trying to reverse the adoption of ASCE 7-16 for reasons not related to the sixth chapter. To prevent this, ASCE’s Structural Engineering Institute is asking its members to support the adoption of ASCE 7-16 during upcoming public-comment hearings at the 2016 ICC Annual Conference, to be held Oct. 19-25 in Kansas City, Mo.
If the standard becomes part of the IBC, it can be adopted into local building codes by jurisdictions in the five western states. “It is hoped the IBC adoption process will occur in 2020,” said Chock.
To date, one vertical refuge center—the Westport, Wash., Ocosta Elementary School, which opened in June—has been built under the new standard.
海啸标准主要考虑脆弱区域的高风险基本结构，而不是单层和商业建筑。涵盖的结构“应为最大考虑海啸的影响，包括静液压和水动力，水寄电碎片的积累以及撞击负荷，沉降和冲洗效应。”
标准的作家进行了概率海啸危害分析，以确定海上海啸振幅。然后，标准的开发过程涉及对累积的水质量的淹没建模，以定义海啸淹没达到其水平极限的地面高度。
Geo-Coded Points
标准的运行数据集包括定义运行位置和高程的地理编码点。土地上的淹没限制是加班点的互连。海啸设计区基本上由淹没极限线和海岸线之间的土地区域组成。
The map-data layers consist of geo-coded inundation limit and run-up reference points, which are organized by segments of coastline for each of the five states. Tsunami Design Geodatabase Information Products will be hosted on an ASCE electronic-database web interface.
The standard took five years to create—considered a short time. But that effort was helped by earlier groundwork, beginning in 2001, when Washington state held a meeting on the impact of waves on structures.
The devastation caused by the 2004 Indian Ocean tsunami led to increased research and development of tsunami warning systems and evacuation strategies. It also provided the impetus for increased laboratory research on tsunami loads and effects, including a 2005 project to develop performance-based tsunami engineering, led by researchers at the University of Hawaii, Manoa, and funded by the National Science Foundation and the Network for Earthquake Engineering Simulation Research (NEESR).
2008年，联邦紧急事务管理机构发布了FEMA P-646：由应用技术委员会（ATC）开发的海啸垂直撤离结构设计指南。“ 2008年的文件是ASCE标准的一个很好的起点，”夏威夷大学，Manoa大学结构工程教授伊恩·罗伯逊（Ian Robertson）说。
2010年，夏威夷大学领导了一个NSF-Neesr项目，以开发浮动障碍的负载表达式。
Based on the research, Chock, principal investigator on the NEESR projects, assembled 30 experts on tsunami modeling and loading and scour effects. He then proposed the ASCE subcommittee, which was officially formed in February 2011.
On March 11, the Tohoku tsunami devastated the northeast coast of Honshu Island, Japan. Members of ASCE traveled to the inundated area and did field surveys, gathering data that was used to validate the earlier laboratory experiments (ENR 5/9/11 p. 12).
罗伯逊说：“现场侦察有助于确认实验室的实验结果确实规模达到最大规模。”“这非常令人放心。”
Work on the standard itself is complete, but there is more to be done. To provide structural engineers with support as they design structures, ASCE plans to publish, likely late next year, “Tsunami Loads and Effects: Guide to the Tsunami Design Provisions of ASCE.” The guide, which will be hundreds of pages, will provide fully worked examples of tsunami-resistant design for structural engineers unaccustomed to the discipline of hydrodynamics, says Robertson, lead author.
根据与ATC的合同，Robertson还正在更新FEMA P-646，以使其与ASCE 7-16保持一致。
The all-volunteer tsunami loads and effects subcommittee consisted of 16 full and 14 associate members. ASCE approved the standard, but only after eight ballots and the clarification of more than 1,000 comments, according to Chock.
“As this work progressed, some outsiders expressed uncertainty about whether this effort was worthwhile,” said Chock, adding, “This was a mission that could not be allowed to fail. To fail would mean there might never be any engineering approach to mitigating tsunami risk.”
