1502 WALL ST IMAGINE CHILDRENS MUSEUM Geotech Report 2022-10-25

Imagine Children's Museum Building Addition Revised Geotechnical Engineering Report Everett, Washington Design Recommendations 11.0 PAVEMENT RECOMMENDATIONS We anticipate that existing pavement will be used for construction staging and access areas. Any new or remedial parking and access areas are expected to be underlain by firm native soils or structural fill. These soils are expected to provide a suitable subgrade for pavement support. Site preparation for areas to be paved should consist of overexcavating to remove the topsoil and the loose/soft portion of the upper soils and expose the underlying stable sediments. Since the density of the upper soils is variable, random, loose/soft areas may exist, and the depth and extent of stripping can best be determined in the field by the geotechnical engineer. In addition, the subgrade should be slightly crowned to drain toward the edges of the paved area. After the area to be paved is overexcavated, the exposed ground should be recompacted to 95 percent of ASTM D-1557. If required, structural fill may then be placed to achieve desired subbase grades. Upon completion of the recompaction and structural fill, a pavement section consisting of 21/2 inches of asphaltic concrete pavement (ACP) underlain by 2 inches of 5/8-inch crushed surfacing top course and 3 inches of 1%-inch crushed surfacing base course is the recommended minimum in areas of planned passenger car driving and parking. In heavy traffic areas, a minimum pavement section consisting of 3 inches of asphalt paving underlain by 2 inches of 5/8-inch crushed surfacing top course and 4 inches of 1%-inch crushed surfacing base course is recommended. The crushed rock courses must be compacted to 95 percent of the maximum density, as determined by ASTM D-1557. All paving materials should meet gradation criteria contained in the current Washington State Department of Transportation Standard Specifications. 12.0 PROJECT DESIGN AND CONSTRUCTION MONITORING At the time of this report construction plans have not been finalized. We are available to provide additional geotechnical consultation as the project design develops and possibly changes from that upon which this report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the foundations depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services and any required contaminated soil remediation support services are not part of this current scope of work. If these services are desired, please let us know, and we will prepare a cost proposal. March 28,2019;Revised April 16,2019 ASSOCIATED EARTH SCIENCES,INC. SGB/Id-190104E001-3-Projects\20190104\KEIWP gage e14