2201 100TH ST SW AD SYSTEMS 2022-03-07

GeoTest Services, Inc. April 25,2017 2201 100th Street Southwest, Everett,WA Job No. 17-0186 soils are fine-grained and can be very moisture sensitive. If fill is to be placed or earthwork is to be performed in wet weather or under wet conditions, the contractor may reduce soil disturbance by: • Limiting the size of areas that are stripped of topsoil and left exposed • Accomplishing earthwork in small sections • Limiting construction traffic over unprotected soil • Sloping excavated surfaces to promote runoff • Limiting the size and type of construction equipment used • Providing gravel "working mats" over areas of prepared subgrade • Removing wet surficial soil prior to commencing fill placement each day • Sealing the exposed ground surface by rolling with a smooth drum compactor or rubber- tired roller at the end of each working day • Providing up-gradient perimeter ditches or low earthen berms and using temporary sumps to collect runoff and prevent water from ponding and damaging exposed subgrades Temporary and Permanent Slopes Actual construction slope configurations and maintenance of safe working conditions, including temporary excavation stability, should be the responsibility of the contractor, who is able to monitor the construction activities and has direct control over the means and methods of construction. All applicable local, state, and federal safety codes should be followed. All open cuts should be monitored during and after excavation for any 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 in depth 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 1H: 1V. 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 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. Slopes for detention ponds should be designed for inclinations of 3H: 1V or flatter. All permanent slopes should be vegetated or otherwise protected to limit the potential for erosion as soon as practical after construction. Seismic Design Considerations The Pacific Northwest is seismically active and the site could be subject to ground shaking from a moderate to major earthquake. Consequently, moderate levels of earthquake shaking should be anticipated during the design life of the project, and the proposed structure should be designed to resist earthquake loading using appropriate design methodology. Page 6 of 13