Engineering Road Inspections

Requesting A Proof-Roll Inspection?

As a prerequisite to County approval and acceptance of new roads, all phases of construction must be inspected and approved by the Land Development Division of DPW. This applies to all residential and commercial roads regardless of the intent to deed over to the County or to keep the road private. Inspectors participate in Proof Roll Inspections and collect & review road testing data.

Inspections are conducted to determine if the Subgrade and Base Course meets compaction requirements. Inspections are conducted on:

Curb & Gutter

Curb & Gutter must be placed on compacted and approved subgrade or base material. Prior to scheduling a curb and gutter proof-roll the Land Development Division of DPW must be in receipt of all density testing data required to be completed at this stage of the construction. The Geotechnical Inspector, Contractor, Project Manager and County Inspector must be present for this proof-roll.

Note: Upon completion of a passing curb and gutter proof-roll, absolutely no excavation or trenching is to be done in a Structural Zone (Roadway or Roadway Easement) without the approval of the Land Development Division of DPW.

Subgrade

Prior to scheduling a sub grade proof-roll, the Land Development Division of DPW must be in receipt of all density testing data (sub grade should must be tested every 250 ft', alternating lanes testing to be completed on cut or fill), required to be completed at this stage of construction. It is the responsibility of the contractor to provide independent density verification prior to proof-rolling and at no cost to Richland County.

After fine grading of sub grade, but prior to placing base material, the sub grade must be proof-rolled with a loaded tandem axle dump truck or pan (no exceptions). The contractor must schedule this inspection and the Geotechnical Inspector, Contractor, Project Manager and County Inspector must be present.

No base course material or curbs should be placed prior to written approval of the sub grade from the Land Development Division of DPW.

Note: Any completed and approved sub grade left exposed for over two weeks or damaged by inclement weather must re-inspected and approved by the Land Development Division of DPW. This may include another proof-roll if necessary in the judgment of the Land Development Division.

Base Course

Placement of base course material is only permitted on a County approved sub grade. Base course material other than graded aggregate base course must be approved

by the Land Development Division (sand clay, cement, geo grid. etc.). All base course materials are to be density tested every 250 feet in alternating lanes with a minimum of 2 tests on any road regardless of the length. Thickness of base course material must be verified at each density test location.

Prior to scheduling a Base Course Proof-Roll the County must be in receipt of all base course density testing and thickness verification reports that meet the following criteria:

Density Testing

The following compaction requirements must be met: Graded Aggregate Base Course (98% of modified proctor density) / Sand Clay Base Course (100% of maximum proctor density) / Cement Modified Earth Base Course (95% of maximum proctor density).

Thickness Verification

If the average base course thickness is found to be deficient by more than 1/2 inch or any individual measurement deficient by by more than one (1) inch, the deficiency will be corrected by scarifying, adding base material, re-compacting and density testing.

Note: For Graded Aggregate Base Course, if base course is thicker than 8 inches, it must be placed and compacted in equal lifts. If base course is less than 12 inches it can be tested as 1 lift. If base course is 12 inches or greater it must be placed, compacted and density tested in equal lifts (12 inches = Compact and test at 6 inches and 12 inches).

Upon completion of the curbing and base course, the contractor shall schedule an inspection to Proof-Roll the base with a loaded tandem axle dump truck or pan (no exceptions). The Geotechnical Inspector, Contractor, Project Manager and County Inspector must be present for this proof-roll.

Note: Any completed and approved stone base left exposed for over one week or damage by inclement weather must be re-inspected and approved by the Land Development Division. This may include another proof-roll if necessary in the judgment of the Land Development Division.