11907 SILVER WAY 2024-01-02 - Laserfiche WebLink

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