17 E MARINE VIEW DR 2019 Geotech Report 2025-10-01

3. Structural fill placed as CSBC below pavements should conform to Section 9-03.9(3) of the 2018 WSDOT Standard Specifications. 4. Structural fill placed as capillary break below slabs should consist of 1-inch minus clean crushed gravel with negligible sand or silt in conformance with Section 9-03.1(4)C,grading No. 67 of the 2018 WSDOT Standard Specifications. Reuse of On-site Fill Solis The majority of the soils encountered in the upper 5 feet of our previous explorations,where excavation is most likely to occur,consisted of sand with varying amounts of silt and gravel(fill material). It is our opinion that the sand may be suitable for use as structural fill on the site during most weather conditions. However, care should be taken to separate out any layers with high fines content or fill with unsuitable organic content or construction debris. Because of the limited quantities anticipated, we recommend that imported structural fill be considered for planning and cost estimating purposes. If the contractor wishes to use on-site soils for structural fill,GeoEngineers can further evaluate the on-site soils for suitability as structural fill when the excavation is under way. Reuse of Existing Asphalt,Base and Concrete Rubble Existing asphalt pavement and portland cement concrete (PCC) rubble may be reused as structural fill if properly crushed during demolition. Recycled PCC rubble and base course materials may be reused as structural fill throughout the project,including under the structure footprints.Recycled asphalt may be used under new pavement and in utility trenches,but should not be used under the floor slabs.For use as general structural fill across the site, the asphalt and concrete rubble should be crushed or otherwise ground up and should meet the gradation requirements for gravel borrow as described in Section 9-03.14(1) of the 2018 WSDOT Standard Specifications. If recycled asphalt and/or concrete will be used under pavement areas,we recommend that it meet the gradation requirements for CSBC as described in Section 9-03.9(3) of the 2018 WSDOT Standard Specifications. Recycled asphalt and concrete should not be used in landscape areas. Fill Placement and Compaction Criteria Structural fill should be mechanically compacted to a firm, non-yielding condition.Structural fill should be placed in loose lifts not exceeding 12 inches in thickness when using heavy compaction equipment and not more than 6 inches when using hand operated compaction equipment. The actual thickness will be dependent on the structural fill material used and the type and size of compaction equipment. Each lift should be moisture conditioned to within about 2 percent of the optimum moisture content to achieve proper compaction to the specified density before placing subsequent lifts. Compaction of all structural fill at the site should be in accordance with the ASTM D 1557 (modified proctor)test method. Structural fill should be compacted to the following criteria: 1. Structural fill placed below floor slabs and foundations should be compacted to 95 percent of the MDD. 2. Structural fill in new pavement and hardscape areas, including utility trench backfill, should be compacted to at least 90 percent of the MDD,except that the upper 2 feet of fill below final subgrade should be compacted to at least 95 percent of the MDD,see Figure 5, Compaction Criteria for Trench Backfill. 3. Structural fill placed as CSBC below pavements should be compacted to 95 percent of the MDD. GEOENGINEER� August3,2018 Page14 File No.0643-015 00