1901 E Dyer Rd - Soils Report - Laserfiche WebLink

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Alliance Residence October 18,2016 J.N.: 2530.00 Page 8 5.2.3 Landsliding Geologic hazards associated with landsliding are not anticipated at the site. Furthermore, the site is not located within an area identified by the California Geologic Survey (CGS) as having potential for seismic slope instability. 5.2.4 Liquefaction Based on our engineering analyses discussed previously, limited thin layers of granular soils are susceptible to liquefaction. However, our analyses also indicate the seismic settlement due to liquefaction is not anticipated to exceed about 1 inch. In consideration of this relatively low magnitude of seismic settlement, no special mitigation is deemed necessary. We also anticipate a sufficient thickness of non-liquefiable soils to be present below the foundations to preclude a loss of bearing while deeper soils are liquefied. 5.3 GROUNDWATER As previous discussed, groundwater was reported beneath the site at a depth of approximately 17 to 47 feet below the ground surface. Groundwater conditions in the future willlikely vary as a result of seasonal variations of rainfall and future site development. Provided the recommendations contained in this report are incorporated into the construction of the project, adverse effects from future groundwater conditions are not anticipated at the site. 5.4 SOIL EXPANSION Based on our review of laboratory test results presented in the referenced reports prepared by GDC and SCG, the near-surface materials within the site are anticipated to possess Medium to High expansion potentials. Provided foundations and improvements are designed in accordance with the recommendations provided herein, adverse effects from expansive soils are not anticipated at the site. 5.5 SETTLEMENT The site is underlain by compressible alluvial soils. Our analyses discussed previously indicate that footings supporting a load exceeding 100 kips could undergo more than 1 inch of settlement. As such, footings that support greater loads will require a blanket of fill below the footing to limit total settlement to 1 inch or less. Specific recommendations are provided in Section 6.3. The garage structures are anticipated to result in column loads exceeding 400 kips. Due to the relatively high column loads, the use of a fill blanket below the footings is deemed unpractical. To mitigate this condition, the garage structures will require support by ground improvement methods such as Geopiers (rammed aggregate piers). Specific design requirements for design of garage foundations on ground improvement technologies will require a specialty design contractor to meet the structural requirements. ALBUS-KEEFE & ASSOCIATES, INC.