Ngaruawahia Section of the Waikato Expressway officially opened

The Ngaruawahia Section of the Waikato Expressway has been officially opened. The opening ceremony took place on Saturday 14th December and was officially opened by Minister Gerry Brownlee. The day’s festivities also allowed the community to walk, cycle, run along the 12.3 km bypass which was a once in a lifetime opportunity before it went live to traffic on 16th December.

DCL were privileged to have been involved in the project. During pavement construction we performed roughness and structural testing utilising our highly specialised survey equipment.

Roughness Compliance Testing is required to ensure a smooth ride to the public and was performed with our Laser Crack Measurement System (LCMS). The LCMS uses a combination of a laser and accelerometer to measure the elevation profile of the road with very high accuracy at highway speeds while eliminating vehicle influence by directly measuring the roads surface. Whilst this project only required roughness testing, the laser based system can also measure rutting, macro texture and automated crack & pothole detection.

Structural Testing was performed utilising our Falling Weight Deflectometer (FWD) prior to surfacing to ensure the road is structurally sound. The FWD simulates the stresses and strains applied to the pavement equivalent to a heavy vehicle. These stresses and strains can lead to surface fatigue and / or subgrade deformation.

The FWD can be used to determine:

  • Deflection and curvature results to target geotechnical testing
  • Structural Number (SNP)
  • Layer moduli results based on pavement layer information.
  • Sub-grade CBR
  • Remaining life and pavement designs based on traffic count data