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.

Excavation operations continued for the Taxiway A3 to A4 connector expansion from Station 35+00 to Station 40+00.

ASEC Engineer Ram Mogulla P.E.  was on site alongside Lead Edge representatives and UES personnel to evaluate subgrade conditions for the proposed A1 to A2 storm drain pipe installation. Based on field observations, it was recommended that the subgrade be undercut an additional 6 inches along the full length of the pipe alignment. Additionally, 6 inches of No. 57 stone is to be placed, resulting in a total of 12 inches of pipe bedding.

With all parties present, including C.W. Matthews Contracting Co., a proof-roll was performed on Taxiway A3 using a loaded tandem axle dump truck. The results indicated that the entire A3 taxiway subgrade was unacceptable.   It was unanimously agreed that the area would require undercutting to a depth of 24 inches, followed by placement of No. 4 stone to stabilize the subgrade of the bottom 12 inches followed by 12 inches of Graded Aggregate Base (GAB).

The proposed connector between Taxiways A3 and A4 was proof-rolled using a motor grader due to concerns regarding the stability of the subgrade and the risk of equipment becoming stuck. Based on these observations, all parties agreed that the connector area will also require a 12-inch additional undercut. This undercut will be backfilled with No. 4 stone placed over geogrid and geotextile fabric to prevent contamination from the underlying wet soils.  All treated areas will include 12 inches of Graded Aggregate Base (GAB) placed above the improved subgrade.

The subgrade for the future Taxiway A4, beginning at the storm drainpipe location and extending west to the existing runway was proof-rolled and determined to be acceptable with no additional remediation required.

The utility contractor excavated a trench at the proposed A4 duct bank location. At an approximate depth of 3 feet, organic material, including tree remnants, were encountered. This condition will be addressed at a later date.

No further observations were made.

Working on A3

Leveling A3

Excavating A3

Proof roll conducted West side of storm drain pipe

proof roll conducted A3

Proof roll conducted between A3 & A4 connector with a motorgrader.

compacting subgrade on A3 & A4 connector

Duct bank trench with buried trees

Duct bank trench

Excavating A3

future A4 taxiway and connector at st. 35+00