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CUSTOM DESIGN & ENGINEERING, INC II h <br />STRUCTURAL ENGINEERING <br />B. Structural The Upper Level addition has a Type 2 Horizontal Irregularity per ASCE 7-16 <br />Table 12.3-1 on the north side, and a Type 4 Vertical Irregularity per ASCE 7-16 Table <br />12.3-2 on the north and west sides. The diaphragm chords at the second floor and roof <br />are required to be developed into the main building structure to transfer lateral forces. <br />See IBC Sections 1604.1, 1604.4, 1613, 1, and 2306. 1. The following comments should <br />be addressed. <br />a. Chords and connections to transfer lateral forces from the addition to the main <br />building should be specified in the framing plans. <br />b. The chords should be developed in the main building diaphragms considering <br />increased loading per Section 12.3.3.4. See also A WC SDPWD-15 Sections 4.1.4 and <br />4.2.6. <br />We have calculated the diaphragm chord forces for the addition (worst case) and <br />have called out collector elements to drag forces from the addition back in the <br />existing structure In both directions Indicated. Please refer to the revised structural <br />drawings. In addition, we have provided new detail to illustrate the connections <br />between the new and existing diaphragms. Forces used in the calculations have <br />been scaled per AWC SDPWD-15 requirements. <br />9. Details for the roof overframing construction should be provided. The details should <br />specify interconnection of the existing and new diaphragm sheathing. See Section <br />R106.1.1. <br />We have provided a roof overframing detail. Also, detail 101S6.1 provides a <br />connection between the new and existing diaphragm sheathing. Please refer to the <br />revised drawings. <br />10, The connection requirements appear to be missing for the new addition Upper Floor <br />Framing Plan on Sheet S2.1. See Sections R106.1.1 and R301.1. The following <br />comments should be addressed.. <br />a. A ledger connection should be included between the addition floor and the existing <br />east building wall. <br />b. Multiple beam connections to the supporting framing appear to be missing <br />This framing information is now being shown on the plans. Please refer to the <br />revised structural drawings. <br />6021 ROOSEVELT WAY NE, SEATTLE, WA 98115 <br />PHONE (425) 266E946 - COENGR.COM <br />