Observations/Finding

Our AS Engineering & Consulting representative, in conjunction with the county engineer, observed a proof-roll test of the North Fields project site. The test focused on the shoulder subsection adjacent to the roadway, a section measuring approximately 165 linear feet by 14 feet wide. A tandem-axled dump truck was used to perform the proof-roll test, with a minimum of five passes executed parallel to the existing road.

During the execution of the test, noticeable subgrade deflections became apparent in two areas – Section A (approximately 8 feet wide by 40 feet long) and Section B (approximately 8 feet wide by 30 feet long). These areas exhibited signs of deflection and pumping of the subgrade soils under the applied load of the dump truck. The precise locations of these issues are outlined in the attached drawing.

In response to these findings, it is recommended to over-excavate the problem areas to a depth of six inches and replace them with an aggregate base course (GAB). Following the placement and compaction of the GAB, a secondary proof-roll test is recommended on the entire shoulder area prior to the start of pavement construction.