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City of Everett Edgewater Creek Bridge Replacement <br /> Notification Center. Utility location marks will be used to verify proposed field <br /> exploration locations prior to development of traffic control plans. <br /> 3.3.3 Generate Geotechnical Work Plan Memo: CONSULTANT will prepare a Geotechnical <br /> Work Plan Memorandum describing exploration means and methods associated with both <br /> Phase 1 and Phase 2 of our exploration program. This work plan will be submitted to the <br /> design team and the City of Everett for review and approval. The work plans will detail <br /> the type, location, and extent of proposed field explorations along with logistics <br /> necessary to perform the work such as traffic control plans and designation of staging <br /> areas. The work plans will also be used for utility locating clearances and for permitting <br /> and right of entries that may be necessary to access the exploration locations. We assume <br /> the City of Everett or TranTech, in support of this project, will acquire and provide any <br /> required permits or right of entries at no cost to CONSULTANT. <br /> 3.3.4 Conduct Phase 1 Explorations (Geotechnical Borings): CONSULTANT will conduct a <br /> series of 4 geotechnical borings geotechnical borings along the bridge alignment to <br /> support various aspects of the design. CONSULTANT proposes to drill one truck <br /> mounted geotechnical boring near each existing bridge abutment(total of 2 borings). <br /> These borings will be drilled to a depth of approximately 75 feet below ground surface <br /> near the location of the existing east and west bridge abutments. Instrumented <br /> groundwater monitoring wells will be installed within both borings to monitor and record <br /> seasonal variations in groundwater levels. <br /> To assess the soil and groundwater conditions at the proposed interior piers, <br /> CONSULTANT proposes to advance two (2)borings through the bridge deck. At each <br /> of the two (2) over-ravine(bridge)boring locations,a nominally 12-inch diameter core <br /> will be drilled through the existing pavement and structural deck. The best location for <br /> these cores will be coordinated with the design team to account for existing utilities and <br /> structural considerations. A very small quantity of water will be used to lubricate and <br /> cool the diamond-tipped core barrel;this water will be contained and collected using a <br /> shop-vacuum. Both concrete cores will be drilled, extracted,and covered with steel <br /> plates the day before drilling is scheduled to commence. <br /> Once the core holes are completed,the exploratory borings will be advanced using the <br /> rotary wash drilling technique. This drilling technique will employ a temporary steel <br /> casing(nominally 8 inch diameter) extending from the bridge deck surface down a <br /> sufficient depth(nominally 20 feet)below the mudline. This steel casing will create a <br /> seal to contain all drilling fluid and soil cuttings such that there is no drilling mud is <br /> released into the ravine. <br /> After each of the boreholes have reached the required target depth of 75 feet below the <br /> ground surface,the boreholes will be abandoned using a bentonite grout slurry in <br /> accordance with Washington State Department of Ecology requirements. <br /> Page 9 of 42 <br />