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P N D <br /> ENGINEERS INC. MEMORANDUM <br /> Date:January 11th,2022 PND No. 204042 <br /> To:Brandon Whitaker(bwhitaker@portofevcrctt.com),Project File <br /> From:Jon Keiser,PE(jkeiser(pndengineers.ccmi),Chris Fornace (cfornace@pndengineers.com) <br /> CC:Chase Castona,PE(ccastonagpndengincers.com),Chris Wiest(cwiest@pndengineers.com) <br /> Project:Jetty Landing Restroom Replacement <br /> Subject:Jetty Landing Restroom Replacement—Foundation Design <br /> The goal of this memorandum is to discuss the seismic design requirements of the new Jetty Landing restroom <br /> structure located at the Port Everett. <br /> This restroom structure will be replacing the existing restroom.The new Jetty Landing Restroom has been designed as <br /> a Risk Category 1 structure in accordance with IBC 2015 to satisfy life-safety requirements.The site is subject to <br /> liquefaction during the design seismic event. It is anticipated that this liquefaction would cause lateral spreading and <br /> differential settlement at the building foundations.Per the geotechnical report for this project,anticipated lateral <br /> displacements could be up to 2.5 feet and differential settlements up to 1 foot.With the designed mat foundation,the <br /> building would be free to displace with the soil. Occupants would be able to safely exit the structure during the design <br /> seismic event;though,these displacements would require major repairs before the building could be used again. <br /> The changes in the International Building Code (IBC) from IBC 2015 to IBC 2018,have more stringent requirements <br /> for designing foundations that are in a liquefaction susceptible location.The requirements of Chapter 12.13 of ASCE <br /> 7-16 provide limits for liquefaction induced displacements,which would be exceeded at this site.To mitigate for these <br /> displacements,ASCE 7-16 requires the use of ground improvements or deep foundations.Either of these options are <br /> not economically feasible for this restroom structure.PND and the Port of Everett are asking the City of Everett to <br /> allow for the requirements of IBC 2018 to be modified per section 104.10 based on"practical difficulties involved in <br /> carrying out provisions of this code...".We are requesting that the City grant an exemption to the seismic displacement <br /> limitations of the structure.The foundation,as designed,is appropriate for the use case of this structure and its <br /> performance has been designed to meet all life safety standards of IBC 2015. <br /> ■ <br /> 0 BRUCF <br /> $.çc0 wnsy1,,c4Z <br /> o War e i°1' S <br /> . 4 32789 0 <br /> �0 I s T E�� c. <br /> �ss/ONAI c <br /> 01/11/2022 <br /> 1736 Fourth Avenue S • SEATTLE,WASHINGTON 98134 • phone 206.624.1387 • www.pndengineers.com <br />