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18TH STREET PEDESTRIAN IMPROVEMENTS 3741 RMT July 03, 2024 74 Over excavation and replacement of unsuitable foundation soils and replacement with 1 approved compacted fill will be compensated as agreed upon with the Engineer. 2 3 8-26.3(1) Base Leveling Pad Installation 4 5 Base leveling pad material shall be placed to the lines and grades shown on the 6 construction drawings, to a minimum thickness of 6" (150 mm) and extend laterally a 7 minimum of 6" (150 mm) in front and behind the CMB unit. 8 9 Soil leveling pad materials shall be compacted to a minimum of 95% Standard Proctor 10 density per ASTM D698 or 92% Modified Proctor Density per ASTM D1557. 11 12 Base leveling pad shall be prepared to insure full contact to the base surface of the 13 concrete units. 14 15 8-26.3(2) CMB Unit Installation 16 CMB concrete units shall conform to the following construction requirements: 17 1) Vertical setback: 1" (25 mm) per course per the design; 18 2) Alignment and grid positioning mechanism fiberglass pins, two per unit 19 minimum. 20 3) Maximum horizontal gap between erected units shall be ≤ 1/2" (13 mm). 21 22 First course of CMB units shall be placed on the leveling pad at the appropriate line 23 and grade. Alignment and level shall be checked in all directions, ensuring that all 24 units are in full contact with the base and properly seated. 25 26 Place the front of CMB units side-by-side. Do not leave gaps between adjacent CMB 27 units. Layout of corners and curves shall be in accordance with manufacturer's 28 recommendations. 29 30 Maximum stacked vertical height of wall units, prior to unit drainage fill and backfill 31 placement and compaction, shall not exceed two courses. 32 33 8-26.3(3) Shear Connector Installation 34 Install shear/connecting devices per manufacturer’s recommendations. 35 36 8-26.3(4) Unit Drainage Fill Installation 37 Place unit drainage fill within CMB units. Unit drainage fill shall be placed within the 38 cores of, between, and behind the units as indicated on the design drawings. Not less 39 than one cubic foot (0.028 m3), of unit drainage fill shall be used for each square foot 40 (0.093 m2) of wall face unless otherwise specified. 41 42 8-26.3(5) Geogrid Soil Reinforcement Installation 43 Geogrid shall be oriented with the highest strength axis perpendicular to the wall 44 alignment. 45 46 Geogrid reinforcement shall be placed at the strengths, lengths, and elevations shown 47 on the construction design drawings or as directed by the Engineer. 48 49