3400 RIVERFRONT BLVD Geotech Report 2022-10-25 (2)

REVIEW COMMENT 16 GeoDesign should expand their discussion to include the effects of liquefaction induced settlement to the soils and structures nearby. Analyses should be performed to show that the proposed improvements can tolerate the liquefaction induced settlement during a design earthquake event per 2012 IBC, and what the total and differential settlement design limits are. The effects of lateral spreading should also be discussed. RESPONSE TO REVIEW COMMENT 16 Our comprehensive geotechnical report for the project will address seismic hazards, including liquefaction, seismic settlement, and lateral spreading. REVIEW COMMENT 17 Page 6, Settlement Monitoring. As discussed in Comment 11, additional settlement plates are needed across the site and along the existing utilities. RESPONSE TO REVIEW COMMENT 17 See response to Review Comment 11. REVIEW COMMENT 18 Page 6. The presence of the large stockpile of fill, which was removed during site grading recently should be evaluated. The presence of the large stockpile will have a significant impact on the settlement predictions for buildings and improvements located within and adjacent to the stockpile footprint. Differential settlement across the boundaries of the fill stockpile should also be addressed. RESPONSE TO REVIEW COMMENT 18 There is a large soil stockpile at the southwest corner of the site that is currently being used to provide surcharge material. Approximately ten years ago, there was also a 30-foot-high surcharge that was placed over most of the western part of the site. The locations of these previous surcharges are shown on Figure 2. We agree that less settlement will occur beneath these areas that have previously been surcharged, which is why we are recommending that additional surcharge not be placed in these areas. We are also recommending that a new surcharge be placed over areas not previously surcharged, unless the City indicates that they do not want certain areas surcharged in order to protect their buried utilities. In our opinion, these recommendations will mitigate the amount of differential settlement that will occur between adjacent areas and reduce the differential settlement to acceptable levels. REVIEW COMMENT 19 Page 7, Imported Soil. The standard of practice is compacting structural fill to at least 95 percent of the maximum dry density(per ASTM D 1557) under buildings and in the upper 2 feet beneath G EODESIGNz 8 Polygon-128-01:0811 15