3313 OAKES AVE 2020-07-14 - Laserfiche WebLink

GeoTest Services,Inc. December 9,2016 3313 Oakes Avenue,Everett,WA Job No. 16-0659 Flexible Pavement Sections—Light Duty We anticipate that asphalt pavement will be used for new access drive and parking areas. We recommend a standard, or "light duty", pavement section consist of 2.5 inches of 1/2-inch HMA asphalt above 6 inches of crushed surfacing base course (CSBC) meeting criteria set forth in the Washington State Department of Transportation (WSDOT) Standard Specification 9-03.9[3]. Alternatively, the owner may wish to substitute the 6 inches of CSBC with 10 inches of Gravel Borrow meeting criteria set forth in WSDOT Standard Specification 9-03.14(1), with the added provision that the percent passing the #200 screen not exceed 5 percent. The Gravel Borrow is more representative of a locally available "pit run", predominately granular, structural fill material. Flexible Pavement Sections—Heavy Duty Areas that will be accessed by more heavily loaded vehicles, semi and garbage trucks, etc. such as the main drive paths, will require a thicker asphalt section and should be designed using a paving section consisting 4 inches of Class 1/2-inch HMA asphalt surfacing above 8 inches of CSBC meeting criteria set forth in the Washington State Department of Transportation (WSDOT) Standard Specification 9-03.9[3]. Alternatively, the owner may wish to substitute the 8 inches of CSBC with 12 inches of Gravel Borrow meeting criteria set forth in WSDOT Standard Specification 9-03.14(1), with the added provision that the percent passing the#200 screen not exceed 5 percent. We are available to further consult, review and/or modify our pavement section recommendations based on further discussion and/or analysis with the project team/owner. The above pavement sections should be considered initial recommendations and may be accepted and/or modified by the site civil engineer based on the actual finished site grading elevations and/or the owner's preferences. Stormwater Design Potential Due to the high fines content, the dense to very dense nature of the native till, and the potential for shallow perched groundwater conditions depending on the time of year, we anticipate that the infiltration potential of this site to be extremely limited. GTS does not recommend that conventional infiltration systems be utilized to manage stormwater on this site. If infiltration facilities are included in the final design, GTS recommends that long-term design infiltration rates be determined by in-situ methods such as PIT (Pilot Infiltration Test) testing. GTS is available to assist with this testing as part of a separate scope of services once a more formal stormwater management plan is available. Alternative means of stormwater management utilizing LID (low impact development) systems, such as pervious pavements and/or raingardens, may be feasible at the project site but should be further evaluated as part of a more comprehensive infiltration study once the construction plan is more fully developed. It is anticipated that such facilities would likely require a pipe at the bottom of the facility to direct treated water towards an approved discharge facility or location. Page 14 of 17