3214 BROADWAY BROADWAY KINECT APARTMENTS 2021-08-11

Comment#10: Along Grid F between Grid 4 and Grid 10, there appears to be a discontinuous shear wall condition between levels I and 2,please provide calculations indicating how overturning forces are resolved due to the discontinuity. Please verb the load path for resolving the overturning moment developed at the level 2 shear wall from the story shear imposed at level 3. If columns located at the shear wall discontinuity are intended to resolve the force couples, please apply the overstrength,0,factor for the design of these columns and beam elements(if applicable)per ASCE 7-10 Sec 12.3.3.3. Please provide diaphragm strength checks for transfer of shear out of the discontinuous shear wall and through the walls located below level 1. Response:The RAM Structural System and RAM Concrete structural analysis model, and current typical wall reinforcing detailing shown on sheet S4.03,takes into account the fact that we are utilizing a continuous concrete wall with the openings designed as perforations within a continuous wall.Therefore,the wall from level 2 to level 3 on gridline F is a continuous wall from gridline 1 to 12 with any overturning boundary requirements at the wall ends.The walls from Level 1 to 2 along gridline F are broken into 2 continuous perforated wall segments.The first extends from gridline Ito the column located north of gridline 4.The second starts approximately 6'-0"North of gridline 10 and extends to the end of wall at gridline 12.The wall from level 1 to the foundation is a solid continuous wall from gridline 1 to gridline 12. MI end wall reinforcing is continuous from the level it starts down to the foundation. In response to your question regarding applying an overstrength 13,factor for the design of the columns,beam and slab elements(if applicable)per ASCE 7-10 Sec 12.3.3.3,it is not necessary to design the beams for an overstrength SI,factor since the In-plane discontinuity in vertical lateral force-resisting elements does not place a demand on the supporting beams from overturning.We have reviewed the load combinations that require overstrength factor,1/,in the design of the columns;our review determined that .r the demand on the columns from seismic loading is low and not part of the controlling t00 %""7 load combinations and therefore overstrength SL was not necessary in the controlling \ _S cd"'� load combination for the columns.See sheets B18-B96 for the column forces and o0 summaries.We did however,design a collector in the 2""floor slab along gridline F to collect the loads due to the wall discontinuity that starts at the column located north of gridline 4 to the edge of door opening located approximately 6'-0"North of gridline 10. 36-#8 collector bars,18 top and 18 bottom,have been added to the 2'Floor Slab Top and Bottom Reinforcing Plans S103C,S103D,S103E and S103F. The Collector bars start 6'-0"South of gridline 4 and extend 12'-0"North of Gridline 10. See sheets B219- B220.We also revised the collector bars on the 3'floor to 6-#8 collector bars at 3"OC top and bottom due to increasing p=1.3.See revisions on sheets 1.04C and 1.04 E at the 3"floor.See sheet B115 for the calculations. Comment#11: Please provide calculations for diaphragm force checks per ASCE 7-10 Sec 12.10. Please indicate in the design calculations which design force governed in the design of the diaphragm. Response:See calculation sheets B101-3117 of the Addendum 5 calculations for the diaphragm forces.Sheets B102-B109 are reports of the diaphragm forces at certain locations in the diaphragms. B110-B113 provide a summary of the forces in the diaphragm segments,with the maximum force being highlighted.The controlling load cases are E6-E9 Seismic-Forces from the RSS model. Lochsa Engineering www.Iochsa.com 1-866-606-9784