2130 E 4th St - REV 1 - Plan - Laserfiche WebLink

Home Browse Search

EARTH STRATA GEOTECHNICAL SERVICES 11 March 30, 2023 Project Number 234812-10A utility easements, under footings, sidewalks, driveways and building floor slabs, as well as within or adjacent to any slopes. Backfill should be placed in approximately 6 to 8 inch maximum loose lifts and then mechanically compacted with a hydro-hammer, rolling with a sheepsfoot, pneumatic tampers, or similar equipment. The utility trenches should be tested by the project geotechnical engineer or their representative to verify minimum compaction requirements are obtained. In order to minimize the penetration of moisture below building slabs, all utility trenches should be backfilled with compacted fill, lean concrete or concrete slurry where they undercut the perimeter foundation. Utility trenches that are proposed parallel to any building footings (interior and/or exterior trenches), should not be located within a 1:1 (h:v) plane projected downward from the outside bottom edge of the footing. SEISMIC DESIGN CONSIDERATIONS Ground Motions Structures are required to be designed and constructed to resist the effects of seismic ground motions as provided in the 2022 California Building Code Section 1613. The design is dependent on the site class, occupancy category I, II, III, or IV, mapped spectral accelerations for short periods (Ss), and mapped spectral acceleration for a 1-second period (S1). In order for structural design to comply with the 2022 CBC, the USGS “US Seismic Design Maps” online tool was used to compile spectral accelerations for the subject property based on data and maps jointly compiled by the United States Geological Survey (USGS) and the California Geological Survey (CGS). The data found in the following table is based on the Maximum Considered Earthquake (MCE) with 5% damped ground motions having a 2% probability of being exceeded in 50 years (2,475 year return period). The seismic design coefficients were determined by a combination of the site class, mapped spectral accelerations, and occupancy category. The following seismic design coefficients should be implemented during design of the proposed structures. Summaries of the Seismic Hazard Deaggregation graphs and test data are presented in Appendix D. 2022 CBC FACTOR (ASCE 7-22) Site Location ˚ (North)˚(West) s 1 ms 1.76 g m1 1.17 g 1.17 g 0.78 g 2130 E 4th St 2/11/2025