The Kaikoura M7.8 earthquake caused widespread damage to the road and rail corridor for approximately 20 km North and South of the Kaikoura township. Over forty major slips inundated the road and rail with more than 750'000 m³ of material from source zones up to 500 meters above sea level. The highly fractured Grey Wacke meant frequent future rockfalls were expected. The rockfall frequency at NS13 created the requirement for a system that attenuated the rockfall energy to a manageable level with no maintenance and easy clearing.
A 6 m RXE-2000 rockfall barrier was modified into a 56 m special attenuator. The attenuator consisted of a 12/3/350 ROCCO® ringnet in the impact zone (first 10 m) and a 7/3/350 ROCCO® tail (20 m). The lighter 7/3/350 ROCCO® tail was selected to enable the attenuated material to pass through into a catchment area at the toe of the slope for clearing/maintenance. The post spacing was between 8 m - 12 m depending on topography. TECCO® G65/3 was selected as the secondary mesh in the impact zone to ensure the smaller (less than 350 mm) high velocity rocks were also attenuated. GEOBRUGG SUPERCOATING® and GEOBRUGG ULTRACOATING® were selected due to the close proximity of the sea and Type III flex heads were required due to poor ground conditions.