3301 SEAWAY BLVD WHOLE SITE 2025-10-30

Sabrina Fandler - City of Everett Public Works Engineering / Permit Services Division February 15, 2017 The onsite soils are subject to periodic shallow slides/slumps due to weathering of the upper layers, particularly during extensive wet periods. As the pond crest is located along the top of the steep slope is there a potential that shallow slides could undermine the pond embankment? The Lock and Load Wall Detail provided does not show a detail for the South Wall. Will the 5/8-inch minus crushed leveling pad be founded 3 feet below ground surface, as shown for the North Wall detail? Our concern is shallow sliding of the near surface soils undermining the foundation of the wall. Response: Please see the attached geotechnical engineer response letter prepared by Terra Associates, Inc. The pavement sections presented in the original geotechnical report seem thin for the areas where heavy trucks will operate. The sections presented for heavy traffic areas are 3 inches of HMA over 6 inches of CRB or 5 inches of full -depth HMA. Using a structural coefficient of 0.42 for HMA and 0.14 for CRB, results in design AASHTO Structural number of 2.1. Using a subgrade resilient modulus of 10,000 psi, typical AASHTO input parameters, and the ESAL value presented in the report, we calculate a required structural number of 2.51 using the program Darwin by AASHTO. Response: Please see the attached geotechnical engineer response letter prepared by Terra Associates, Inc. We believe that the responses above, together with the enclosed revised plans and documents, address all of the comments in your memorandum dated October 21, 2016. Please review and approve the enclosed documents at your earliest convenience. If you have questions or need additional information, please contact me at this office. Thank you. Respectfully, � � r Costa Philippides, P.E. Project Engineer CP/hd 17798c.004.doc enc: As Noted cc: Greg Bertch, Bertch Capital Partners Kathy Craft, Craft Architect Daniel K. Balmelli, Barghausen Consulting Engineers, Inc.