3000 ROCKEFELLER AVE ADMIN BLDG WEST 2022-05-13

Mr. Bob Egleston August 2, 2018 page 4 Structure Comment MKA Response 16d. The loading inputs appear to include the 15 psf partition loads as a dead load instead of a live load. See IBC Section 1607.5. 21f. The load combinations appear to be horizontal forces only. Verify where the vertical component is included. 21 g. Include the input file for the automatically -generated load cases. 23b. The participating torsional mass is only 65.6% per page 4027. The participating mass shall be minimum 90% per ASCE 7-10 Section 12.9.1. Note that the analysis requires a lot of modes to reach the 90% threshold, which can adversely affect the overall analysis. Verify if the sources of the small modes is attributed to non -lateral motions of the building system, and if they can be eliminated. Verify the analysis accurately models the response of the building. 23c. The calculation of the response scale factors on page 4026 are not clear. Provide documentation clarifying the scale factors. MAGNUSSON KLEMENCIC ASSOCIATES Partition load was taken as 15psf unreducible live load at surface load type "Office" and does not occur at other load types. Partition load is noted as "PLL" and is located on the Ord column from the right in the previously submitted calculations (see pages 2004, 2008, 2010, & 2012). The 15 psf noted under the "DL" column is for superimposed dead load. The vertical component of seismic load was accounted for in the Wall PMM Reinforcement design that was included in the originally submitted calculation package (section 2.6). A sample pier demand worksheet has been included with this response to clarify how the vertical effects were considered. A screenshot of the load case input screen in ETABS indicating accidental torsion is included in the supplemental calculation package submitted with these comment response. ASCE 7 Section 12.9.1 indicates 90% mass in each of the orthogonal horizontal directions considered. This does not require 90% mass in torsion response. The strength scaling factor that is input into the ETABS model is the gravity constant (386.1 in/s2) divided by the system response modification coefficient R=5 (386.1 /5 = 77.22). Note that since Vdyn is more that 85% of Veer in both directions as shown on page 4026, no additional scaling is required.