Observations/Finding

As requested, the site was visited by our AS Engineering and Consulting (ASEC) representative for the purpose of providing quality control inspection and testing services. Visual observation techniques were employed to verify compliance with project drawing/specifications, applicable codes, and materials submittals. The following observations were observed on site this day.

On the above date our representative was on site to observe the grading contractor continue to place fill for building Lots #37 thru 34. The fill placement was compacted using a vibratory sheep-foot roller (placed in lifts). The writer performed density testing using a Troxler Nuclear gauge model 3430, serial no. 91643.The density tests were performed at the basement slab elevations and the front of the lot elevations. The writer also performed a field proctor today with results being (98.0 pcf @17.2% moisture content) with the soil description of a multi-colored fine to medium sandy silt. After recompacting efforts all compaction results met job requirements.

The writer also observed installation of an 8″ ductile iron pipe (DIP) water line pushed through a sleeve across the Parkway south of the sanitary sewer manhole #5. In order to install the water line today (very muddy conditions on site) mud was tracked onto previous placed base stone for the Parkway between manholes #6 and 9.  The existing subgrade between manhole #5 and 6 was also found to be disturbed. Standing water was present on the base rock between manholes #7 and 8 near the storm curb inlet. It was recommended to cut a ditch to drain this water into a swale ditch removing the water from the base rock and to limit all traffic off the subbase stone and subgrade soils to prevent further soil contamination of the rock and to prevent additional subgrade soils undercutting.

Observed the pipe contractor backfill an 8″ PVC sanitary line between manhole structures #12 and 13 using excavated rock fill which was placed in suitable compacted lifts using a vibratory sheep-foot roller. Density tests couldn’t be performed on the rock and soil mixture (rock fill). Compaction efforts were found to be visually satisfactory. The contractor is bedding all pipe on No. #57 stone and placing clean fill over top of the pipe. The contractor also continued installing 8″ ductile iron pipe (DIP) between manholes #13 and 14 where heavy continuous hard rock was encountered without any fine soil materials present. The contractor was reminded that using predominately all rock fill requires monitoring to see if placement is acceptable. The contractor was reminded that at least four feet of clean fill should be placed over all rockfill (and predominately hard rock fill). All excavated rock until 4:00 pm was removed using the 490 excavator without requiring hammering. The contractor did spend one hour hammering hard rock between 4:00 and 5:00 pm. which was three feet too high in bottom of trench.

We appreciate the opportunity to be of service to you on this project. If you have any questions regarding this report, please feel free to contact us. We will be more than happy to discuss it with you.

Performing density tests lots # 37 thru 35

Observation of contamination mud on sub base stone between sanitary sewer manholes #9 and 6

Performing density tests

Contamination and saturation on base stone

8" ductile iron water line pushed through sleeve east side of roadway south of manhole #5

Excavation of sanitary sewer trench showing rock fill between manhole #12 and 13

Standing water on base rock at Parkway between manhole #7 and 8,reconmmended to trench off and limit additional traffic.

Excavated sanitary sewer trench

Excavated sewer trench removing large boulder

Excavated sewer trench showing hard rock full depth of trench excavation.

490 backhoe excavating hard rock

Compacting rockfill using vibratory sheet foot roller

Sub grade observation being disturbed at Parkway

Excavation pushing 8" ductile iron pipe through sleeve