1304 80TH ST SW EVERETT SCHOOL DISTRICT 2018-01-02 MF Import

Subsurface Exploration and Everett Bus Facility Geotechnical Engineering Report tEverett, Mashimrron Design Recommendations geotechnical engineer, placed in maximum 10-inch loose lifts with each lift being compacted to at least 95 percent of the modified Proctor maximum density using ASTM:D-1557 as the standard. The contractor should note that any proposed fill soils should be evaluated by AESI prior to their use in fills. 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 in which the amount of fine-grained material (smaller than the U.S. No. 200 sieve) is greater than approximately 5 percent (measured on the minus U.S. No. 4 sieve size) should be considered moisture-sensitive. Use of moisture-sensitive soils in structural fills should be limited to favorable dry weather and near-optimum subgrade moisture conditions. The on-site till soils are suitable for use as structural fill provided they can be dried to near- optimum moisture content as they contained significant amounts of silt and are considered moisture-sensitive. If the upper 2 feet of the existing fill materials can be moisture-conditioned and recompacted to a firm and unyielding condition, they can be us-d for pavement support. Construction equipment traversing the site when the soils are wet can cause considerable disturbance. If full is placed during wet weather or if proper compaction cannot be obtained due to wet subgrade or soil conditions, a select material consisting of a clean, free-draining gravel and/or sand should be used. Prec-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus U.S. No. 4 sieve fraction and at least 25 percent greater than the No. 4 sieve. 7.2 Construction Monitorin¢ A representative from our firm should inspect the stripped subgrades and be present during placement of structural fill to observe the work and perform a representative number of in- place density tests. In this way, the adequacy of the earthwork may be evaluated as fulling 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 ensure uniformity or acceptable performance of a fill. As such, we are available to aid you in developing a suitable monitoring and testing frequency. 8.0 PAVEMENT DESIGN RECOMMENDATIONS We anticipate that asphalt paving will be used for the new drive and bus parking area. Asphalt pavement design is a compromise between initial cost and expected design life. In order to provide a 20-year design life with normal maintenance for areas that support passenger car driving and parking, we recommend a pavement section consisting of 3 inches of asphalt surfacing above 4 inches of crushed surfacing base course per Washington State Department of Transportation (WSDOT) Standard Specification 9-03.9(3) above a granular (till or structural November 28, 2015 ASSOCMMD EARFH SCIENCE$INC. EGAe-EE 60202-eb11a,vaseo2uawr Page