3313 OAKES AVE 2020-07-14 - Laserfiche WebLink

GeoTest Services,Inc. December 9,2016 3313 Oakes Avenue,Everett,WA Job No.16-0659 evidence of instability. If instability is detected, the contractor should flatten the side slopes or install temporary shoring. Temporary excavations in excess of 4 feet should be shored or sloped in accordance with Safety Standards for Construction Work, WAC 296- 155-66403. According to WAC 296-155-66403, temporary unsupported excavations in the near- surface fill and native soils encountered at the project site are classified as Type B and may be sloped as steep as 1 :1 (Horizontal: Vertical). All soils encountered are classified as Type C in the presence of groundwater seepage. Flatter slopes or temporary shoring may be required in areas where groundwater flow is present and/or unstable conditions develop. Temporary slopes and excavations should be protected as soon as possible using appropriate methods to prevent erosion from occurring during periods of wet weather. If used for this project, we recommend that permanent cut or fill slopes be designed for inclinations of 2H: 1V or flatter. Detention ponds or stormwater facilities should be sloped at 3H: 1V or flatter. All permanent cut slopes should be vegetated or otherwise protected to limit the potential for erosion as soon as practical after construction. Pavement Subgrade Preparation Selection of a pavement section is typically a choice relative to higher initial cost and lower long term maintenance or lower initial cost and more frequent maintenance. For this reason, we recommend that the owner participate in the selection of proposed pavement improvements planned for the site. Site grading plans should include provisions for sloping of the subgrade soils in proposed pavement areas, so that passive drainage of the pavement section(s) can proceed uninterrupted during the life of the project. The area of proposed pavements should be stripped of any topsoil or deleterious material prior to placement of structural fill. Structural fill placed to establish subgrade elevation should be compacted to a minimum of 95 percent of its maximum dry density, as determined using test method ASTM D1557. Prior to the placement of base-course and paving materials, the exposed pavement subgrade should be proof rolled. Proof rolling should be accomplished with a loaded dump truck, large self-propelled vibrating roller, or equivalent piece of equipment. The purpose of this effort is to identify possible loose or soft soil and recompact disturbed areas of subgrade. Proof rolling should be carefully observed by GeoTest personnel. Areas exhibiting significant deflection, pumping, or over-optimum moisture content soils that cannot be readily compacted should be overexcavated to firm soil. Overexcavated areas should be backfilled with compacted granular fill. During periods of wet weather, proof rolling could damage the exposed subgrade. Under these conditions, GeoTest personnel should observe subgrade conditions to determine if proof rolling is feasible. Prevention of road-base saturation is essential for pavement durability; thus, efforts should be made to limit the amount of water entering the base course. Page 13 of 17