Description

In November 2019 a change was made to Acceptable Solution B1/AS1 preventing it from being used on liquefaction-prone ground. This change takes effect from 29 November 2021. The change was made as a result of the experience of the Canterbury earthquakes, and subsequent recommendations made by the Royal Commission of Inquiry.

The change brings the rules that are currently in place in Canterbury to the rest of New Zealand, meaning robust foundations will be required for liquefaction-prone ground. The new rules will be mandatory across the country after 28 November 2021, ensuring new buildings are being built safely and strongly enough to withstand liquefaction risks.

This change will provide more clarity to local councils, Building Consent Authorities (BCAs), engineers and developers, resulting in safer and more resilient buildings.

Scope

This Guide includes:

• Background
• Impact of 'Good Ground' definition change
• Changes to foundation design
  • Regional liquefaction hazard maps
  • Consider seismicity risk
• Example - foundations for NZS 3604-type residential buildings
  • Review of regional hazard information
  • Review of local seismicity and shallow ground conditions
• Resources