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A licensed surveyor should be retained to establish monuments on the shoring and the <br />surrounding ground prior to excavation. Such monuments should be monitored for <br />horizontal and vertical movement during construction. Results of the monitoring program <br />should be provided immediately to the project structural (shoring) engineer and LGC for <br />review and evaluation. <br />4.1.6 Fill Placement and Compaction <br />From a geotechnical perspective, the onsite soils are suitable for use as compacted fill, provided <br />they are screened of rocks greater than 6 inches in maximum dimension, organic material, and <br />construction debris. Areas prepared to receive structural fill and/or other surface improvements <br />should be scarified to a minimum depth of 6 inches, brought to at least optimum -moisture <br />content, and recompacted to at least 90 percent relative compaction (based on ASTM Test <br />Method D1557). The compacted fills underlying the proposed parking structure should be <br />compacted to a minimum relative compaction of 95 percent. The optimum lift thickness to <br />produce a uniformly compacted fill will depend on the type and size of compaction equipment <br />used. In general, fill should be placed in uniform lifts generally not exceeding 8 inches in loose <br />thickness. Placement and compaction of fill should be performed in accordance with local <br />grading ordinances under the observation and testing of the geotechnical consultant. <br />In general, oversized material shall not be placed within 10 vertical feet of finish grade or <br />within 2 feet of future utilities or underground construction. Rebar should be removed from <br />concrete rubble prior to burial or mixing with fill. Oversize material may be incorporated into <br />design fills in accordance with our standard grading details. Pulverized asphalt concrete paving <br />or crushed Portland cement concrete from demolition of the existing improvements may be <br />mixed in the fills in a 80/20 blend (with the 20 percent being crushed asphalt or concrete) with <br />no material over 6-inches in maximum dimension; or be placed in a rock disposal. <br />If possible, import soils should contain no materials over 6 inches in maximum dimension and <br />have a low expansion potential. <br />4.1.7 Trench Backrill and Compaction <br />The onsite soils may generally be suitable as trench backfill provided, they are screened of <br />rocks and other material over 6 inches in diameter and organic matter. Trench backfill should <br />be compacted in uniform lifts (generally not exceeding 8 inches in compacted thickness) by <br />mechanical means to at least 90 percent relative compaction (per ASTM Test Method D 1557). <br />If trenches are shallow and the use of conventional equipment may result in damage to the <br />utilities; clean sand, having sand equivalent (SE) of 30 or greater, should be used to bed and <br />shade the utilities. Sand backfill should be densified. The densification may be <br />accomplished by jetting or flooding and then tamping to ensure adequate compaction. A <br />representative from LGC should observe, probe, and test the backfill to verify compliance <br />with the project specifications. <br />Project i y 66n,61 18 — 832 1 3 , 2021 <br />