Concrete Cloth™ Headwall Scour Protection – Graham, NC

WATER/WASTEWATER   STRUCTURAL STRENGTHENING 

PROJECT OVERVIEW

The NCDOT replaced a double barrel culvert with a larger single barrel culvert under Ivey Road about a half-mile east of Route 87 in Graham, NC. The old culvert experienced scour left of the culvert inlet, and NCDOT wanted to ensure that scour didn’t occur at the face of the new headwall in the same location. Initially, it was the NCDOT’s intention to install Concrete Cloth GCCM at the inlet location only.

However, after a rain storm less than two weeks after the initial installation, scour at the end of the southwest wing wall beyond the culvert outlet occurred and additional scour protection was installed using Concrete Cloth GCCM.

SOLUTION

NCDOT chose to install Concrete Cloth GCCM at a location that had been a previous problem.

Where the previous scour hole existed, Concrete Cloth GCCM matting would be attached to an angle that was attached to the headwall. Concrete Cloth GCCM matting was attached to the headwall and the edges were buried. The buried toe was covered with riprap. While not needed for stability, soil anchors were placed as a demonstration of how Concrete Cloth GCCM, an erosion control measure, would dovetail with a stabilization technique. The Concrete Cloth GCCM was hydrated with stream water using a small pump. All work was completed within a couple hours.

The area around Graham received between 1.5 and 3 inches of rain, causing flooding, high velocity water and turbulence around the inlet and outlet of the new culvert. There was now scour at the end of the southwest wing wall.

The Concrete Cloth GCCM remained in place and performed well through the weather event, so it was decided to use Concrete Cloth GCCM to repair the scour that occurred at the end of the southwest wing wall. After the slope was reshaped, Concrete Cloth GCCM was placed at the end of the wing wall with 10 soil anchors.

RESULTS

Based upon the positive performance at this site, NCDOT is considering using Concrete Cloth GCCM at other sites.

PROJECT DETAILS
Application: Headwall Scour Protection
Client: NCDOT
Location: Graham, NC
Installation: 2012

There was no damage to the scour protection after the repair using Concrete Cloth GCCM.
Pre-installation scour to the left of the inlet.
Concrete Cloth GCCM installed at the inlet headwall where vegitative control was ineffective.
Additional scour outside the inlet needing protection due to ineffective riprap.
Additional Concrete Cloth GCCM installed outside the inlet for scour protection.