Observations/Finding

At the request of the client’s representative, our AS ENGINEERING AND CONSULTING, LLC (ASEC) representative visited the job site to observe the contractor’s work activities from a quality standpoint to verify compliance with project drawings/specifications, applicable codes, and materials submittals and conducted QC testing per the project drawings and specifications.  The following observations were made on site this shift:

Summary: Upon arrival at the site, backfilling operations were observed for the 24-inch black corrugated pipe installation between manholes A2 to A3, as shown by the provided photos. The backfilling process involved the placement of 6 to 12-inch lifts using a Komatsu PC360 excavator, followed by compaction using a trench packer and a ride on vibratory sheeps-foot. A 3/8-inch probe rod was utilized and deflected to a depth of approximately 1 inch.

Compaction Testing: Compaction testing was conducted using a Troxler 3430 (Serial Number 39042) with an optimum density-moisture relationship of 94.8 Dry Density (DD) and 25% Moisture (M).

• Between A2 and A3 (Green Space Area):
  • Test #1 at -4 feet from the surface yielded a DD of 87.9 pcf and 22.2% Moisture, meeting the 90% compaction requirement.
  • Test #1 at -4 feet below the surface recorded a DD of 86.7 pcf and 22.8% Moisture, also meeting the compaction standards.
  • Test #1 at -3 feet below the surface resulted in a DD of 93.8 pcf and 21.7% Moisture, indicating satisfactory compaction.
  • Test #1 at -2 feet below the surface showed a DD of 92.1 pcf and 21.5% Moisture, meeting the desired compaction criteria.
• New Section (Lots 10 and 11):
  • A 12-inch lift of soil was placed, with Test #1 at -4 feet below the surface showing a DD of 93.4 pcf and 25.2% Moisture.
  • Test #2 at the same depth recorded a Dry Density of 85.0 pcf and 28.7% Moisture, prompting a recommendation for scarification and aeration to lower soil moisture and recompacting to achieve optimal compaction.

Recommendation: A recommendation was given to scarify the soil to lower moisture levels and recompact to achieve the desired compaction standards. However, this action was not completed before the end of the shift.

Conclusion: Despite the progress made in backfilling and compaction efforts, further action is required to address moisture levels and achieve compaction in the new section.

Lift at lots 10 and 11

Testing lots 10 and 11

trench packer utilization

manhole A3