2721 WETMORE AVE MARQUEE APARTMENTS 2023-06-28

S i Plan Check Number B1906-031 2721 Wetmore Avenue Response to wood frame comments from Second Building Review,October 18, 2019 effects, as clarified in 2015 NDS SDPFWS Figure 4A(a)and (d) attached in the supplemental calculations. We confirm that diaphragm shears are within allowable limits.As requested by the reviewer, shear walls were added at the north, east and south sides of the building as shown on Sheet S2.10A. At the west side,there are no available walls to use as shear walls, so the diaphragm remains as an open sided diaphragm on the west side. Reference Figure 4A(d)with a diaphragm aspect ratio of L'/W'of 0.20:1 which is substantially less than SDPWS 4.2.5.1 limit of 1.5:1 and is acceptable.At the west end,the configuration of party walls perpendicular to the available interior shear walls supports shears in both directions account for all required torsional effects of the open ended diaphragm. North— South shears perpendicular to the party wall results in direct shears to the interior shear walls and torsional restraining shears in the long party shear walls. These torsional restraining shears are less than the controlling direct shear from the shears in the east-west direction (plane of the party walls.) Item 40 Calculations confirming the reinforced 14"thick PT slab is adequate for the applied holdown loading was submitted in previously submitted structural calculations. Reference supplemental structural concrete calculations dated November 11,2019 Pages 431 to 506 which included load combinations with code required amplified holdown loading and vertical seismic effects have been checked for punching shear and reinforcement. Reference Sheet S1.30 and S1.31 for holdown details and added reinforcement at each holdown. Please note that holdown pull-out capacity in a reinforced 14"PT slab is not a controlling failure mode when holdown forces are kept relatively small compared to larger holdown loading in thinner slabs. This is confirmed for a 14"PT slab in the attached supplemental calculations. Item 41 The reviewer has requested structural calculations for the shear wall sill plate anchorage based on concrete anchor capacity.We do not agree that the governing failure mode is anchor capacity in concrete. Anchor shear capacity is governed by the shear capacity of the anchor bolt in wood as previously submitted. Reference 2015 NDS Table 12E and Table 2.3.2 Load duration factors. Previously the copy from an earlier version of NDS was referenced but the capacities have not changed. See supplemental calculations for Table 12E and previously submitted anchor spacing calculations based on wood anchor capacity per the NDS. Concrete capacity is many times greater than the wood capacity and OK by inspection. RE footnote 3 of Table 12E which states that this table is based on concrete strength of F'c of 2500 psi or greater.When concrete strength is greater than 2500 psi, concrete is not the governing failure mode. Our PT slab concrete is specified as 5000 psi concrete so we meet this requirement. Miscellaneous Item 42 42a. As requested the"basis of design"elevator rail loading has been added to 17/S6.02. Loading will be confirmed in forthcoming elevator submittal. Thyssen Krupp has confirmed that loading given include the effects of impact and do not need to be increased. 42b. RE Detail 16/S6.02 for the mounting plate detail at concrete levels. Loading is found on Detail 17/S6.02. 42c. RE Details on Sheet S9.01 for elevator rail mounting plates at the wood frame levels. Detail 12/S9.01 is at each floor rim. At each floor the rim blocking matches the stud depth and therefore is confirmed to be full depth. Detail 13 and 14/S9.01 occurs only at the elevator penthouse wall which is the only location where rail mounting plates attach to blocking attached to bundled studs. The attachment of the rail system to the mounting plates is by elevator manufacturer. 42d to 42f. See attached supplemental calculations confirming the supporting framing and mounting plate connections. F1 is not concurrent with F2 as the seismic is considered in one direction at a time. Elevator rail lateral loads are concurrent with gravity loading which has been considered. 42g. The requirement for accommodating 3/8"of vertical shrinkage per floor in included in all wood frame plan note#5 on each framing sheet. The attachment and detailing for accommodating wood Page 13 N