3301 SEAWAY BLVD MAGNIX 2023-12-06

Drew Martin From: Drew Martin Sent: Wednesday, November 3, 2021 12:49 PM To: paulg@weaverarch.com Subject: City of Everett Permit Services: 3301 Seaway Blvd (132108-001) - First Building Review Hello, Paul. This email follows up on our conversation regarding this project. I have some questions for the structural engineer. This email will effectively take the place of the review letter. Depending on the responses, we may be able to redline the drawings without new drawings being produced; this may include taping in additional details. Structural Comments 1. The structural has a 3-sided lateral system, omitting a frame on one side. The structure appears to potentially have a Type 1a or 1b Horizontal Irregularity per ASCE 7-16 Table 12.3-1. The structural calculations do not appear to include a torsional analysis. An analysis should be performed, including accidental torsion per Section 12.8.4.3 and amplification per Section 12.8.4.3 (ELFP used for analysis), and the design revised as needed. Supplemental calculations should be submitted for review. Note that the deflection check preceding the RISA model appears to be a basic deflection analysis and does not include torsional effects. 2. A story drift analysis should be performed per ASCE 7-16 Sections 12.8.4.3 and 12.12.1. The drifts should not exceed the limits of Table 12.12.1. 3. The connection of the diaphragm to the vertical frames is required to comply with ASCE 7-16 Section 12.3.3.4 if a torsional irregularity occurs. Additional calculations and details may be required. 4. The design loads are required to include a redundancy factor of 1.3 if a Type 1b Horizontal Irregularity occurs. 5. Verify if a connection is provided between the roof panels serving as the diaphragm and the center frame line. A detail should be included. 6. The anchorage design calculations appear to include the overstrength factor per ACI 318-14 Sections 17.2.3.4.3(d) and 17.2.3.5.3(c). However, it appears the base input loads for tension and shear may be the net loads from the applicable LRFD load factors. The overstrength factor is required to be applied to the seismic component only, not the net uplift. The calculations should be revised as needed. 7. Continuing with the previous comment, the vertical load should include the vertical seismic effect per ASCE 7-16 Sections 12.4.2 and 12.4.2.2. 8. Pending review of the previous two comments, it appears that the unmodified column connection types for two and three anchors are sufficient with the 5/8" Hitli HAS rods. Verify these should be specified at the unmodified base plates. See also Comment 12 below. 9. The design of the tension -only brace connections is based on a reduced design load, where the load determined by analysis (i.e., 2.7 kips) has been reduced by the 160% load factor for the strap short-term increased capacity (i.e., strap expected strength under short-term loading). This is not correct. See AISC 341-16 Section F2.6a. The maximum load should be increased using the overstrength factor for a resulting ASD connection demand of 2.7*(52=2.0) = 5.4 kips. This exceeds the 3.44 kip screw capacity. 10. The columns at the intersection frames (i.e., the corners) should be designed for the orthogonal load effects per ASCE 7-16 Section 12.5.4. 11. The columns should be designed for the strength requirements per AISC 341-16 Section D1.4a. 12. The column base plates and stiffeners should be designed per the requirements of AISC 341-16 Section D2.6. Please let me know if you have questions.