CITY PROJECT - 1821 & 1823 E Chestnut Ave - Plan

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ASSOCIATED SOILS ENGINEERING, INC. Project No.: 7160.23 2860 Walnut Avenue, Signal Hill CA 90755 January 23, 2024 Tel: (562) 426 -7990 * Fax: (562) 426 -1842 Page 10 liquefaction. It is typically exemplified by the formation of vertical cracks on the surface of liquefied soils, and usually takes place on gently sloping ground or level ground with nearby free surface such as drainage or stream channel. Since there is no liquefaction potential at the Site, as per discussed in Section 4.2.1 above, the potential for the occurrence of lateral spreading is also nil at the Site. 4.2.5 Tsunamis and Seiches: Due to the elevation of the Site and absence of nearby waterfront, hazard from a tsunami is considered very low. Seiches are rhythmic movements of water within a lake or other enclosed or semi-enclosed body of water, generally caused by earthquakes. Since no lakes or other bodies of water lie on or near the Site, the hazard from seiches is not present at the Site. 4.2.6 Flood Hazards: The Site was located on the ESRII/FEMA Hazard Awareness site, as shown on Figure 4, National Flood Hazard Layer FIRMette. The Site is not located within the limits of the 100-year flood plain per FEMA Flood Insurance Rate Map (Map No. 06059C0277J, map revised December 3, 2009), and is located outside an area of 0.2-percent-annual-chance flood. 5.0 GEOTECHNICAL CONSIDERATIONS AND RECOMMENDATIONS Based on the results of field exploration, laboratory testing, and engineering analysis, it is ASE's geotechnical opinion that the major geotechnical factors affecting the design and construction of the Building include the following: 1. Soil disturbances as a result of site demolition, clearing and excavation operations. 2. Presence of loose, low density soils within the zone of foundation bearing strata. 3. Excavation and construction of new footings/foundations located adjacent to or near existing building foundation that might undermine stability. Therefore, it is of essential importance that the embedment depth of any new footing planned next to the existing footing be the same as the embedment depth of the existing footing. This will ensure that: a) no soils beneath the existing footing would be undermined resulting in the bearing support to the existing footing being compromised, and b) no undesirable surcharge would be imposed on the existing footing from and adjoining new footing. In consideration of the above factors, it is ASE’s opinion that overexcavation and backfilling with properly compacted fill in the areas of the Building, as recommended herein, will be essential to reduce unfavorable static settlements of underlying soils, and to provide satisfactory bearing stratum for the Building. The