3000 ROCKEFELLER AVE ADMIN BLDG WEST 2022-05-13

Mr. Bob Egleston Apgust 2, 2018 Page 5�F Structure Comment MKA Response 26. The comment asked for clarification that different floor weights representing the new and existing construction have been used. Identify where the calculations verify these weights. 27. This comment does not appear to be addressed by the submitted calculations as indicated. Please specify the pertinent calculation pages. 28. This comment does not appear to be addressed by the submitted calculations as indicated. The plans do not appear to include a structural element developing the new building chord into the existing diaphragm at Grid F/13. This comment does not appear to be addressed by the submitted calculations as indicated. Please specify the pertinent calculation pages. MAGNUSSON KLEMENCIC ASSOCIATES The various structural system weights noted on pages 4014-4021 of the previously submitted calculations are divided by the gravitational constant 32.2 ft/s2 to determine the applied floor mass input in ETABS. Refer to Section 5 (PDF page 178-184) of the previously submitted calculations. Collector and chord forces were all increased by 1.25. Please note that in the calculations, this 1.25 factor was mistakenly called rho and was either applied to the demand force or required minimum area for each condition. Refer to section 5 of the previously submitted calculations (PDF page 176 & lower half of page 184). The total chord force to be developed is small (30k). The (2) #6 chord bars along grid 12.1 are hooked into the Grid F shear wall. The existing columns and C10 perimeter beam in the existing building all are connected into the new grid F shear wall with headed studs. See details 6 & 10/S-603 to see load path. The existing N-S W16 beams are moment connected into the columns which by inspection adequately develops the demand chord force from the building addition into the existing building. The existing C 10 channels are also directly connected to the existing diaphragm via new collector plates (see details 10/S-601 & 13/S-601) which provides additional redundancy for developing the small chord force from the building addition. Due to the notch in the southwest corner of the addition slab, additional reinforcement was added to adequately develop the chord reinforcement into the grid F shear wall and existing connected elements. See sheet S-261 for revised diaphragm reinforcement plans. Requested calculation is included in attached supplemental calculations.