Observations/Finding

As requested, an ASEC representative visited the project site from 09:00 AM to 03:00 PM to provide quality control inspection and testing services. Visual observation techniques were employed to verify compliance with project drawings, specifications, applicable codes, and approved material submittals.

The drilling work between Manhole 9A and A10 was in progress by Advance Explosive contractor. Three drilling machines were engaged in drilling operations. The holes were drilled at approximately 7 ft by 7 ft spacing using a 3.5-inch bit. Depth checks were randomly performed and confirmed with the drill operator’s log sheet. In total, the three drilling machines completed 8 holes at a depth of 30 ft and 37 holes at a depth of 18 ft, with the rock hitting range between 0 ft and 13 ft.

Additionally, rock drilling was conducted in Lot #15, where 42 holes were drilled, and the rock was encountered between 0 ft and 3 ft.

The sewer line backfilling work was in progress between Manhole A5 and A6. Recommendations were provided to avoid using rock diameters larger than 4 inches around the sewer pipe and manhole. The placement of layers should not exceed the allowable thickness specified in the project specifications. Compaction around the manhole was advised to be carried out using a small roller.

The embankment work using rock-drilled materials was in progress for Lots #11 and 12, where qualitative tests were performed using a 3/8″ diameter probe rod. It was also recommended to the grading contractor to scarify about 2 ft below the finished grade to remove the rocks.

We appreciate the opportunity to provide our services on this project, and should there be any questions regarding this report, please feel free to contact us.