1400 W MARINE VIEW DR WATERFRONT PLACE APARTMENTS 2022-04-04

acceleration matched 0.198g. A composite undrained shear strength of 1700 psf was found to produce a yield acceleration of 0.198g. The slope stability displacement calculations for this case are presented in Appendix A.2. 3.2.3 CDSM Strength and Area Replacement Ratio The CDSM composite shear strength can calculated using the following equation(Bruce et al.2013): Scomp = ARR•Sdm + (1—ARR)•S„, Eqn. 3-1 where ARR is the net area replacement ratio and Sdm is the shear strength of the CDSM material,which is calculated as: Sam= 112'fr'fc• .dm,spec Eqn. 3-2 Where f is a factor that accounts for the difference between peak unconfined strengths and confined strengths at large strains, f is a factor that accounts for the curing time relative to the 28-day uniaxial compressive strength, qdm spec. A value of 0.8 was used for f and f was calculated using the following relationship: f� = 0.187*In(t in days) + 0.375 Eqn. 3-3 A value off, =1.27 was calculated using a time, t of 120 days since at least this must time will pass before full building loads or design seismic shaking is expected to occur. The CDSM strength(at 120 days)for gdm,spec value of 160 and 220 psi are 11,707 psf and 16,097 psf,respectively. Using Sdm =1 1,707 psf(based on gdn,spec =160 psi)and an area ratio of 0.14 and Sn, =190 psf in Equation 3-1 yields: Sco,np = 0.132*16,097psf + (1-0.131)•190psf=1,710psf So the minimum ARR required to meet the lateral spreading requirements is 13.2%. In our design we arranged the shear panels(the panels parallel to the direction of lateral spreading displacement)such that this minimum shear panel ARR value was met. In our design when the cross panels and individual columns are counted the total ARR over each building footprint is 17.1%for the North building and 20.7%for the South building. 3.3 CDSM Bearing Capacity A calculation of the CDSM bearing capacity was performed and is presented in Appendix A.3. The calculations show that individual columns have an allowable bearing capacity of 150 kips and rows of columns have an allowable bearing capacity of 56 k/ft. The 150 kip allowable capacity is based on gdm,spec = 220 psi whereas the 56 kip/ft is based on qdm spec =160 psi. Thus,the design qdm spec is higher for the individual columns than for the panels. DCI Engineers has reviewed our proposed CDSM layout and determined that,based on the allowable bearing capacity values indicated above,the layout provides sufficient support for the applied foundation loads. DCI Engineers is the structural designer of the mat slab foundation and we understand they have 4 Our design and analysis assume the soil between the DSM will remain liquefiable under the design seismic event. The shear reinforcement provided in the design is not sufficient to prevent liquefaction under the design shaking. Preclusion of liquefaction is not practical for this site,nor is it necessary in order to meet the design requirements. 71Page