1300 W MARINE VIEW DR WATERFRONT PLACE APARTMENTS 2022-07-28

) sr • Email dated 7/6/18 From Michelle Kinsch (Tiscareno)transmitting DCI mark-up of HBI conceptual layout w/note deleting 6 each exterior piles. • Email dated 7/10/18 From Jon Potter (DCI-Engineers) transmitting drawing with dowel locations and added CDSM columns at the North building main entrance. • Email dated 7/10/18 From Michelle Kinsch (Tiscareno) transmitting comment to add 1 each CDSM Column at the North building main entrance. • Vapor Barrier and Mitigation Plans,Sheets C7.01 and C7.02,dated 23 July 2018,prepared by CPIH Consultants. If any of these documents are changed or altered in any way,HBI may need to modify our design. 2.2 Ground Improvement Design Criteria The ground improvement design criteria for the project are defined in the BOD Memo by GeoEngineers. The design seismic criteria are: • Site Class F(ground motions based on Site Class E since building period is<0.5 seconds) • Modal earthquake magnitude 6.61 • Mean earthquake magnitude 6.88 • Less than 2 inches of lateral spreading displacement' As is customary, our analyses used the larger of the modal and mean magnitudes, Mw =6.9. The static design criteria are: • Allowable axial capacity of 150 kips per individual isolated column • Static settlement of 1 inch The ground improvement has been designed to work in conjunction with the concrete structural mat foundations shown on the structural sheets referenced above. The mat foundation is 16 inches thick with thickened edge sections that are 2 feet thick. The structural design of the mat has been performed by DCI assuming support is provided solely by the CDSM ground improvement. 2.3 Geotechnical Conditions The subsurface geotechnical conditions are described in the Geotechnical Report and BOD Memo referenced above. GeoEngineers performed 21 cone penetration tests(CPTs)to depths ranging from 23 to 65.5 feet below ground surface and four borings to depths of up to 56.5 feet. The borings indicate the site is covered with an approximately 3-inch thick layer of crushed rock base course. Under the base course, the soil conditions include: FILL consisting predominantly of poorly graded sand with silt (SP-SM) and silty sand (SM) with occasional interbeds of sandy silt and elastic silt(ML to MH). The SP-SM and SM materials are generally very loose to loose.The ML/MH materials are generally soft. The boring logs show occasional wood debris within the fill. In the building areas the fill extends to depths ranging from 25 to 29 feet below ground surface. 1 The BOD Memo also mentions an option for 6 inches maximum lateral spreading displacement. However,we understand based on discussions with the design team that 2-inch criterion has been adopted for the project. 2 The BOD Memo indicates an allowable bearing pressure of 4,000 psf. However,we understand that this would have been applicable to shallow spread footings that were under consideration at the time. With the current mat foundation design,we understand based on the 4 June 2018 email from DCI Engineers that the required axial capacity is 150 kips for individual columns(isolated columns are not interlocked in panels with others). 2IPage