1133 S Austin St & Unit# 2 - Plan

Home Browse Search

Page 4 Based on the State of California SEISMIC HAZARD ZONES Map, Newport Beach Quadrangle, the subject site is located within a potential liquefaction zone. Therefore, the owner(s) of this property should be aware of the risks associated with the potential liquefaction such as structural distress due to the potential differential settlement caused by the potential liquefaction. A detailed liquefaction study with a 50 ft deep test hole has been performed. Liquefaction Analysis The provisions of the Special Publication 117A [SP117A], “Guidelines For Evaluating and Mitigating Seismic Hazards In California”, Published in 2008 by the State of California, Department of Conservation, Division of Mines and Geology have been followed. A 50 ft. deep boring was drilled by using a hollow stem flight auger drill rig. The approximate location of the boring is depicted on the attached Site Plan/Geotechnical Map. The geotechnical log of the boring is included in Appendix B. As the boring was advanced, relatively undisturbed soil samples were secured at selected depth intervals using a steel tube sampler lined with I-inch-high, thin wall brass rings. The sampler was driven into the undisturbed earth materials using a standard 140 pound "automatic-trip" steel hammer freely dropped 30-inches. Standard Penetration Testing (SPT) was also performed at selected depth intervals; a bulk sample of near ground surface earth materials was secured from the drill cuttings. The approximate sample depths are noted on the boring log. The samples were transported our laboratory for testing. After completion of sampling, the boring was backfilled with the drill cuttings. Moisture content and dry density testing was performed on the "undisturbed" ring samples. Moisture content testing was performed on the SPT samples. Atterberg Limits (i.e., liquid limit, plastic limit, and plasticity index) tests were performed on cohesive soils. The test results are included in Appendix C. Note: To determine if fine- grained/clayey soils are susceptible to liquefaction, the screening criteria of SP117A were used: Clayey soils having Plasticity Index (PI) smaller than 12 and moisture content greater than 85% of the Liquid Limit (LL) are susceptible to liquefaction. Therefore, the percentage of soil finer than 0.075 mm by washing the soil through the N 200 sieve in accordance with ASTM Test Method D 1140, Atterberg Limits (LL, PL, PI) and in-situ moisture contents were determined on selected samples; and the test results are included in our Laboratory Test Results and/or Boring Log. A copy of the computer print-outs of the results of our liquefaction analysis using the computer program prepared by CivilTech software is included in Appendix E. Based on the results of our liquefaction analysis, the calculated total and differential settlements due to liquefaction are 3.94 and 1.971 to 2.602 inches, respectively.