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CITY OF EVERETT WEST MARINE VIEW DRIVE/ALVERSON AND 41 ST ST/GRAND AVE <br />PEDESTRIAN IMPROVEMENTS <br />STATE FUND# HLP-PB15(032) <br />WO #3630 July 25, 2024 <br />129 <br />1 The geogrid shall be laid horizontally on compacted reinforced backfill and attached to <br />2 the CMB wall units. Place the next course of CMB units over the geogrid. The geogrid <br />3 shall be pulled taut and anchored prior to backfill placement on the geogrid. <br />4 <br />5 Geogrid soil reinforcement shall be continuous throughout their embedment lengths <br />6 and placed side-by-side to provide 100% coverage at each level. Spliced connections <br />7 between shorter pieces of geogrid or gaps between adjacent pieces of geogrid are not <br />8 permitted. <br />9 <br />10 8-26.3(6) Reinforced Backfill Installation <br />11 Place and compact reinforced backfill behind CMB units and unit drainage fill. Follow <br />12 wall erection closely with reinforced backfill. Reinforced backfill shall be placed, <br />13 spread, and compacted in such a manner that minimizes the development of slack in <br />14 the geogrid and installation damage. <br />15 <br />16 Reinforced backfill shall be placed and compacted in lifts not to exceed 6 inches where <br />17 hand operated compaction is used, or 8 10 inches where heavy self-propelled <br />18 compaction equipment is used. Lift thickness shall be decreased to achieve the <br />19 required density, as needed. <br />20 <br />21 Reinforced backfill shall be compacted to a minimum of 95% Standard Proctor density <br />22 per ASTM D698 or 92% Modified Proctor Density per ASTM D1557. The moisture <br />23 content of the backfill material prior to and during compaction shall be uniformly <br />24 distributed throughout each layer. <br />25 <br />26 Only lightweight hand operated equipment shall be allowed within 3 feet (1 m) from the <br />27 tail of the CMB unit retaining wall. <br />28 <br />29 Tracked construction equipment shall not be operated directly upon the geogrid <br />30 reinforcement. A minimum reinforces backfill thickness of 6 inches is required prior to <br />31 operation of tracked vehicles over the geogrid. Tracked vehicle turning should be kept <br />32 to a minimum to prevent tracks from displacing the reinforced backfill and damaging <br />33 the geogrid. <br />34 <br />35 At the end of each day’s operation, the Contractor shall slope the last lift of reinforced <br />36 backfill away from the CMB units to direct runoff away from wall face. The Contractor <br />37 shall not allow surface runoff from adjacent areas to enter the wall construction site. <br />38 <br />39 8-26.3(7) Bond Breaker Geotextile <br />40 Before placing bond breaker geotextile, remove foreign and loose materials from base. <br />41 Place bond breaker geotextile less than 72 hours before covering it with pavement. <br />42 Except when pavement is placed against previously placed pavement, extend the <br />43 bond breaker at least 6 inches beyond the limits of the planned concrete placement. <br />44 <br />45 Place bond breaker geotextile in a wrinkle free manner. Overlap adjacent sheets a <br />46 minimum of 8 inches in the same direction as the concrete pour. Overlap no more than <br />47 three layers at any location. Secure the bond breaker sufficiently that it remains in <br />48 place during concrete placement. Ensure that no concrete will get under the bond <br />49 breaker. Fastener spacing of 6 feet in the field and 3 feet along edges is recommended <br />50 in order to prevent fabric displacement. <br />51