202 ALDER ST Geotech Report 2018-01-02 MF Import

1 , Proposed View Ridge Su6surface Ecploration, Geologir Hazards. Infilrration Potenrial, Elementarv Schoof Replacement and P�eliminary Geotechnical Engineering Report Everett, N'ashington Preliminary Design Recommendations ' After recompaction of the exposed ground is tested and approved, or a free-draining rock course is Iaid, structural fill may be placed to attain desired grades. Structural fill is defined as , non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts, with each lift being compacted to 95 percent of the modified Proctor maximum densiry using ASTM:D 1557 as the standard. In the case of roadway and utiliry trench filling, the ' backfill should be placed and compacted in accordance with current City of Everett codes and standards. The top of the compacted fill should extend horizontally outward a minimum ' distance of 3 feet beyond the ]ceations of the roadway edges before sloping down at an angle of 2H:1V. , The contractor should note that auy proposcd fi!I soils must be evaluated by AESI prior to their use in filis. This would require that we have a sample of the material 72 hours in advance to perform a Proctor test and determine its field compaction standard. Soils iu which the amount ' of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Use of moisture-sensitive soil in structural fills should be lirnited to favorable dry weather , conditions. The native and existing fill soils present on-site contained significant amouuts of silt and are considered moisture-sensitive. These on-site soils aze expected to be suitable for reuse in structural fill applications during dry site and weather conditions when moisture ' conditions can be controlled by aeration and drying, as needed. The native soils and existing fills can only be used for structural fill specifically allowed by the project plans and ' specifications. If fill is placed 'nring wet weather or if proper compaction cannot be obtained, ' a select import material consisting ^f a clean, free-drainir,g gravel and/or sand should be used. Free-draining fill consisu of non-organic soil with the amount of fine-grained material limited ' ro 5 percent by weight when measured on the minus No. 4 sieve fraction with at least 25 percent retained on the No. 4 sieve. ' A representative from our firm should inspect the stripped subgrade and be present during placement of structural fill to observe the work and perform a representative number of in-place densiry tests. In tnis way, the adequacy of the earthwork may be evaluated as filling ' progresses, and any problem areas may be corrected at that time. It is important to understand that taking random compaction tests on a part-time basis will not assure uniformity or ' accepeable performance of a fill. As such, we are available to aid the school district in developing a suitable monitoring and testing program. ' ]1.0 FOUNDATIONS ' Spread footings may be used for building support when founded directly on undisturbed advance outwash sediments, or on structural fill placed above suitablc native deposits, as ISep�ember 22, 2010 ASSOGATED EARTH SGENCES, INC. nwcne KE100155A1 PrqeruiSOlC0155IKE�WV Page 17 '