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Swenson Say Faget <br /> STRUCTURAL ENGINEERING <br /> 2124 Third Ave,Suite 100 <br /> Seattle,WA 98121 <br /> O 206.443.6212 <br /> 934 Broadway,Suite 100 <br /> Tacoma,WA 98402 <br /> O 253.284.9470 <br /> July 20,2017 �? ssfengineers.com <br /> James Bronder <br /> Associate Engr. Plans Examiner <br /> City of Everett Public Works Department <br /> 3200 Cedar St,Everett,WA 98201 <br /> Re: Responses to June 21,2017 City of Everett Review Comments <br /> Plan check#B1706-031 <br /> CHCSC Rucker Avenue <br /> Everett,WA <br /> James, <br /> This letter is in response to our conversation on July 20,2017 regarding Structural plan review comment <br /> 1. The review comment is regarding the use of the redundancy factor, p,for design of the braced frame <br /> retrofit system. <br /> We recognize the importance of redundancy in new building structural design and also in seismic <br /> retrofit design. However, as discussed,we do not feel that the application of the redundancy factor to <br /> this particular building retrofit design is appropriate for the following reasons: <br /> The existing building is regular in shape and has a complete lateral load resisting system consisting of <br /> steel moment frames although frame connections are non-compliant with current moment frame <br /> connection design. None of the existing building frame system is being removed or modified as part of <br /> the retrofit. The moment frame system is independent of the new braced frame system being installed <br /> as part of the seismic retrofit. Therefore,there is built-in redundancy between the moment frame and <br /> braced frame systems. <br /> ASCE 41-13,Seismic Evaluation and Retrofit of Existing Buildings,defines redundancy as the quality <br /> of having alternative load paths for lateral loads in a structure, allowing the building to remain stable <br /> following the failure of any single element. We do not believe that removal of a brace in the braced <br /> frame system will result in a loss of stability in the structure or result in significant reduction in story <br /> strength as the moment frame system becomes the alternate load path and that load path is not weakened <br /> from its current strength as part of the retrofit. Further,we do not believe that removal of a single brace <br /> will result in an extreme torsional irregularity for similar reasons. <br /> Please call if you have any questions regarding the above information. <br />