2514 RAINIER AVE Geotech Report 2022-10-25

4,00 I amec I foster wheeler 4.1 SITE PREPARATION I Preparation of the project site for construction of the new school building expansion will include the following elements: I ► Temporary erosion and sediment control; ► Removal and demolition of building structures, asphalt, and concrete walkways within the I campus redevelopment footprint; ► Removal or abandonment of utilities within the planned redevelopment footprint; I ► Clearing, stripping, and grading; and ► Subgrade compaction. I The paragraphs below discuss our geotechnical comments and recommendations concerning site preparation. Erosion Control Measures: Prior to disturbing the ground surface with earthwork, temporary erosion I and sediment controls should be implemented. The project civil engineer, with reference to the Snohomish County Standards, should prepare plans and specifications to prevent erosion and runoff I during construction. The contractor will need to understand that design plans and specifications represent the minimum requirements, and additional measures and modifications may be needed that are specific to the construction activities and the weather. I Demolition: One of the first steps in site preparation will likely consist of decommissioning of utilities followed by demolition and removal of all or most of the existing building structures in the redevelopment footprint. Removal of the asphalt, concrete walkways, and curbs is also planned. Stripping of any surface vegetation and/or topsoil will be part of the demolition process. Associated I underground structural elements or utilities, such as old footings, stemwalls, and drainpipes, should be exhumed as part of this demolition operation. Excavations created during demolition should be backfilled and compacted with structural fill in accordance with the recommendations contained herein. Pipes more than 2 feet below any future excavations could be filled with concrete or lean mix and left in place. However, if any significant structure is planned over an abandoned utility line, the I utility trench backfill should be evaluated and possibly replaced to meet the proposed structural needs. Any demolition performed adjacent to footings that will remain should be done so as to not I undermine or potentially destabilize the structural elements. Any such demolition should be performed under the observation of a geotechnical engineer. III Amec Foster Wheeler I 8 Project No.6-917-18116-0 \\Sea-fs1\WordProc\_Projects\18000s\18116 Everett School District\Geotech Report\Revised\2017_10-19_Everett Middle School Geotech_Sx.docx