In February 2011, a 6.2 magnitude earthquake caused devastation to buildings, roading and infrastructure in Christchurch, New Zealand. Over 6,500 people were injured and 185 people lost their lives.
Following the earthquake, Christchurch City Council (CCC) was faced with a major rebuild of the city’s water and wastewater pipeline network. Due to its flexibility and ductility, the existing polyethylene (PE) watermain pipeline network performed remarkably well during the quake and CCC chose PE as the material of choice for new water and wastewater pressure pipelines.
As the rebuild began, a large number of construction workers arrived in the city to work on the rebuild. Many of the workers were inexperienced in the installation of PE pipelines and specifically the installation of electrofusion jointing used to connect the pipework. The lack of knowledge resulted in wide spread failures of newly installed pipeline joints.
CCC implemented testing and monitoring oversight which installers were required to follow. The result was electrofusion weld failures fell from 30% after the earthquake, to less than 1% within the next 18 months. The system is still in place today and mandatory weld testing shows failures account for less than 0.3% of all welds tested.
Author
- Mark Habel, Technical Manager, Plasson Australia