ITEM 5 EXHIBITS A-H - Laserfiche WebLink

BLACK AVENUE RESIDENTIAL DEVELOPMENT 648-26-1 Page 9 6.2 SURFACE DRAINAGE Surface water runoff should not be allowed to pond adjacent to building foundations, slabs-on- grade, or pavements. Hardscape surfaces should slope at least 2 percent towards suitable discharge facilities; landscape areas should slope at least 2 to 3 percent away from buildings. Due to the high expansion potential of the near-surface soils, retention, detention, or infiltration facilities should be spaced at least 10 feet from buildings, and preferably at least 5 feet from slabs-on-grade or pavements. The near-surface soils at the site consist of non-expansive clays that would likely be categorized as Hydrologic Soil Group D, and are expected to have infiltration rates on the order of 0.2 inches per hour or less. In our opinion, the shallow clayey soils will significantly limit stormwater infiltration. SECTION 7: FOUNDATIONS 7.1 SUMMARY OF RECOMMENDATIONS On a preliminary basis, the proposed residential structures may be supported on shallow foundations consisting of rigid mat foundations. 7.2 SEISMIC DESIGN CRITERIA We assume the project design will be based on the 2019 California Building Code (CBC). The 2019 CBC provides criteria for the seismic design of buildings in Chapter 16. The “Seismic Coefficient” used to design buildings are established based on a series of tables and figures addressing different site factors, including the soil profile in the upper 100 feet below grade mapped spectral acceleration parameters based on distance to the controlling seismic source/fault system. Based on our experience in the vicinity and review of local geology, the site is underlain by deep alluvial soils with typical SPT “N” values between 15 and 50 blows per foot. Therefore, the site is designated as Site Class D (determined). The mapped spectral acceleration parameters Ss and S1 were calculated using the web-based program ATC Hazards by Locations, located at https://hazards.atcouncil.org/, based on the site coordinates presented below and the site classification. We assume the structural engineer would intend to take Exception 2 per Chapter 20 of ASCE 7-16, and as such, a full Ground Motion Hazard Analysis will not be required. The table below lists the various factors used to determine the seismic coefficients and other parameters. On a preliminary basis, the proposed residential structures On a preliminary basis, the proposed residential structures may be supported on shallow be supported on shallow We assume the project design will be based on the 2019 California Building Code (CBWe assume the project design will be based on the 2019 California Building Code (CB 2019 CBC provides criteria for the seismic design of buildings in Chapter 16.2019 CBC provides criteria for the seismic design of buildings in Chapter 16. Coefficient” used to design buildings are established based on a series of tables and figures Coefficient” used to design buildings are established based on a series of tables and figures addressing different site factors, including the soil profileaddressing different site factors, including the soil profile mapped spectral acceleration parameters based on distance to the controlling seismic mapped spectral acceleration parameters based on distance to the controlling seismic Based on our experience in the vicinity and review of local geology, the Based on our experience in the vicinity and review of local geology, the site is underlain by deep alluvial soils with typical SPT “N” values between 15 and 50 blows persite is underlain by deep alluvial soils with typical SPT “N” values between 15 and 50 blows per Therefore, the site is designated as Site Class D (determined).Therefore, the site is designated as Site Class D (determined). acceleration parameters Sacceleration parameters Ss and Sand S11 were calculated using the webwere calculated using the web by Locations, located at by Locations, located at https://hazards.atcouncil.org/https://hazards.atcouncil.org/ below and the site classification.below and the site classification.We assume the structural engineer would intend to take We assume the structural engineer would intend to take Exception 2 per Chapter 20 of ASCE Exception 2 per Chapter 20 of ASCE The table below lists the various factors used to determine the seismic The table below lists the various factors used to determine the seismic