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C. Restoration Requirements <br />1. Trenches and Multiple Window Cuts. The restoration of trenches and multiple <br />window cuts shall be as follows, provided that single window cuts made by more <br />than one Utility Purveyor that are associated with a private development project <br />will be considered multiple window cuts for restoration purposes: <br />All trench backfill shall be per WSDOT/APWA Specification 7-08.3(3) and <br />these Standards, using bank run gravel or CSTC conforming to <br />Specifications 9-03.19 or 9-03.9(3), respectively. Backfill shall be placed to <br />the bottom edge of the existing asphalt or within 6-inches of existing road <br />grade, whichever is greater, in successive layers not exceeding 6 inches in <br />loose thickness. Each layer shall be compacted with mechanical tampers <br />to 95 percent of maximum density as determined in ASTM D1557. <br />Verification of backfill compaction shall be required and shall bear the stamp <br />and signature of a professional engineer licensed in the State of <br />Washington. The verification of backfill compaction test shall be submitted <br />to the County prior to the placement of the overlay required by EDDS <br />Section 8-05.C.i.iii below. <br />ii. After placing a tack coat on the existing asphalt edges, the final patch shall <br />be constructed with 6-inches of compacted HMA placed in the trench cut <br />up to finished grade per WSDOT Standard Specifications Division 5-04. <br />iii. After the backfill compaction has been verified and placement of the <br />compacted HMA final patch, a full -width overlay consisting of 2-inches of <br />compacted HMA shall be placed per WSDOT Standard Specifications Section <br />5-04. In preparation for overlaying an existing asphalt road, the ends of <br />the overlay project and any areas where matching existing curb or <br />pavement will be necessary shall be planed in accordance with Standard <br />Drawing 4-165. Should the final patch not be of satisfactory surface texture <br />and grade, an asphalt pre -level shall immediately be done to ensure a <br />smooth driving surface during the period before the final asphalt overlay. <br />iv. Full -Width Overlay Limits for a Single Lateral Trench <br />The full -width overlay limits for a single lateral trench extend laterally from <br />the curb line or edge of pavement to curb line or edge of pavement and <br />longitudinally along the roadway from 10 feet before the first pavement cut <br />line of the trench to 10 feet beyond the last pavement cut line of the trench <br />as illustrated in Figure 8 - 1. <br />8-6 Engineering Design and Development Standards <br />September 17, 2021 <br />