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.

Our ASEC representative was on site for the observation/testing of the placement of fill/backfill. Upon arrival to the site, ASEC observed the contractor excavating topsoil from the slope of the detention pond to install a headwall BA1 to BA2. ASEC discussed with the contractor about the backfilling of this structure and recommended to use structural fill to backfill to at least 2 feet above the pipeline. The contractor said that the excavated topsoil from the bank was structural fill. This is incorrect, as this topsoil was stripped from the Lots #1 through #4 area and contains a large amount of organics such as root matting and large branches and roots. ASEC informed the contractor that structural fill should be used around the pipeline to prevent any settlement around the pipe. Once they are 2 feet over the structure, they could resume using topsoil in the slope. ASEC observed the contractor placing topsoil around the structure and actively attempting to compact the topsoil around the structure. ASEC performed probe rod testing around BA1 and BA2. Probe rod testing showed unstable soils around these structures (as shown in the pictures below).

The contractor continued placing lifts approximately 6 inches to 8 inches across Lots #1 through #4 and the deceleration lane in-between BC4.0 and BC4.1. The lifts were compacted using an 815 sheeps-foot roller and a smaller HAAM vibrating sheeps-foot roller. ASEC preformed density testing in this area and provided all test results to the contractor. ASEC watched as loaded trucks rolled across the lifts to check for stability. There were no signs of severe pumping or rutting present. Some of the trucks appeared to be bringing in rocks larger than 2 feet in diameter mixed in with the fill. Our representative recommended to remove any large rocks from the fill being placed in the top 4 feet of final grade. The contractor requested an ASEC supervisor to visit the site to discuss rock size in lifts and topsoil installation. The contractors and ASEC reviewed site plans together. At this time, there did not appear to be any specifications in the site plans about rock size. ASEC recommended that we maintain keeping any rocks larger than 2ft in size out of the top 4ft of final grade unless otherwise specified and as per the geotechnical subsurface report recommendation.

ASEC has requested multiple times to stop equipment/give proper space when testing with a nuclear density guage. It is recommended to give ASEC at least 50 feet in all directions while using a nuclear density gauge as per safety requirements. Besides being a safety precaution, it also helps prevent any false readings during testing due to vibrations from equipment. The contractor has not been following the requests of our field representative. As displayed in the photos below, the contractor will operate their equipment within 10 feet of ASEC during testing with a nuclear density guage. The contractor has stated “they do not want to stop equipment if they do not need to”. ASEC supervisors have discussed this with Daniel and Tyler (Foreman with NG Grading). The contractor said they will maintain a safe distance and allow ASEC to safely conduct their testing.

Our field representative reached out to Mr. Scott Wood with Pulte to discuss how they want the contractor to install topsoil. Per our conversation with Mr. Wood, ASEC informed/recommended that the contractor install topsoil in an approximately 1-foot layer over a preexisting/cut slope. If the contractor is building up a slope in a fill area, then they need to maintain at least a 15-foot zone away from any structural building pads. It is expected for the contractor to install topsoil in the same manner as structural fill and then cut back the slope to finial grade to clean it up. This information was discussed with superintendent Daniel with NG Grading. This information will also be discussed again on the following workday.

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.

large rocks in fill

operating equipment around ASEC during testing

deceleration lane

installation of BA1 to BA2

topsoil used as backfill around BA1 to BA2

topsoil used as backfill around BA1 to BA2 failing probe rod test

topsoil used as backfill around BA1 to BA2 failing probe rod test

topsoil used as backfill around BA1 to BA2 failing probe rod test

topsoil used as backfill around BA1 to BA2 failing probe rod test

topsoil used as backfill around BA1 to BA2 failing probe rod test

topsoil used as backfill around BA1 to BA2 failing probe rod test

lots #1 - #4 area

front detention pond

commercial lot area by connex

installation of BA1 to BA2