Dropout Repair Hapokopoko – DuraMesh®

In June 2015 there was a large flood event that caused substantial road damage to several parts of SH4 between Whanganui and Raetihi. Hapokopoko Curve Rock was one of the sites that was majorly affected, there was a large amount of scouring due to the high river level, that reduced the road way to a single lane for approximately 250m. Higgins Contracting who managed the NOC (Network Outcome Contract) for the area, were responsible to provide a repair.

Design

The engineers at BECA were required to design a cost-effective suitable solution that gave the required performance and was readily available and quick to construct. A 70 degree DuraMesh® MSE (Mechanically Stabilised Earth) wall was chosen for the top half of the drop out area with a rock riprap at the bottom to help protect the toe from any future river action. Also as lane width was a problem, the DuraMesh® system proved to be a great option to maximise the available area meaning the finished surface and road barriers were able to be brought as close as possible to the wall edge.

Installation

Mills Albert Ltd was selected as the sub-contractor to construct the wall. Right from the initial proposal through to the completion of the project, the Cirtex team provided the necessary information and on-site support required to help this job be a success. Overall it was a fantastic solution allowing the asset to be reinstated better than its original condition and providing safer access to the road users, this was a great project to be a part of.

The DuraMesh® used provided the following benefits to the project:

• Simple fast installation
• Cost effective & durable
• Flexible design options