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Mr. Calvin Vander Veen <br />Vander Veen Construction <br />Plan Check Number: B1908-021, First Structural Review <br />November 1, 2019 <br />Lateral System: <br />12. The seismic load on structural calculation page 11 include the weight of the addition only. The <br />new and existing structures are tied together and cannot behave independently. A lateral <br />analysis shall be performed evaluating the load distribution to both the new and existing <br />elements. Note that the original building was constructed in 1977 and likely lacks comparable <br />construction, stiffness, and detailing to the new construction. The new wall elements in each <br />wall line shall resist 100% of the lateral loading unless a distribution based on relative <br />stiffnesses is performed. The structural design may need to be revised. See IBC Sections <br />1604.4 and 1613.1, and ASCE 7-10 Sections 12.7.3 and 12.12.3. <br />13. The addition is connected to the original building to create a single structure. The elements <br />interconnecting the addition to the existing structure shall have a minimum capacity per ASCE <br />7-10 Section 12.1.3. Calculations substantiating the interconnection of the new and existing <br />structures should be submitted for review. This shall be in addition to the general design <br />requirement to provide a complete load path for the lateral force resisting system. See IBC <br />Sections 1604.4 and 1613.1, and ASCE 7-10 Section 12.12.3. <br />14. The building has been evaluated and loads distributed considering a flexible diaphragm <br />assumption. However, the exterior cantilever floor creates an open -front structure. The design <br />of the building shall be revised considering a rigid or semi -rigid analysis. The analysis shall <br />consider the entire building including the existing portion. Calculations substantiating the <br />distribution of forces considering the relative stiffnesses of the shear walls shall be submitted <br />for review. The calculations shall include revised documentation for the design of the shear <br />walls, diaphragms, and holdowns. Alternatively, additional shear walls and drag framing shall <br />be provided to eliminate the open -front condition. See IBC Section 2307.1, and AWC SDPWS- <br />15 Sections 4.2.5 and 4.2.5.2. <br />15. Continuing with the previous comment, the structure shall be designed for torsional effects. <br />Documentation evaluating the structure shall be submitted for review. See IBC Sections 1613.1 <br />and 2306.1, ASCE 7-10 Sections 12.8.4.1, 12.8.4.2, and 12.8.4.3, and AWC SDPWS-15 Section <br />4.2.5.1. <br />16. The design of the wood shear walls on structural calculation pages 14 and 15 appear based on <br />the Individual Segment method per AWC SDPWS-15 Section 4.3.5.1. However, the Lower Floor <br />Plan 1/S-1 and Main Floor Plan 2/S-1 reference Detail 3/S-3 for strapping around the wall <br />openings, indicating the shear walls should be designed using the Force -Transfer method per <br />AWC SDPWS-15 Section 4.3.5.2. Calculations substantiating the design of the shear walls using <br />the appropriate method shall be submitted for review. Note that the wall piers on Sheet A04 <br />and A06 does not appear to be consistent with the plans. In addition, the wall piers on Sheet <br />A04 do not appear to satisfy the limitations of Section 4.3.5.2. The structural design may need <br />to be revised. See IBC Section 1604.1, 1604.4, 1613.1, and 2307.1. <br />O3200 Cedar Street 425.257.8810 everetteps@everettwa.gov <br />Everett, WA 98201 425.257.8857 fax its. <br />Cage 4 of 6 <br />