Balancing the risks of earthquake-prone council buildings

Published November 2021

Living in Aotearoa means living with frequent earthquakes. Fortunately, most earthquakes are not even felt, but occasionally, they are severe enough to damage buildings and threaten lives.

Since the Kaikōura and Christchurch earthquakes, new legislation has led to many earthquake-prone buildings sitting empty, resulting in community facilities and services being suspended. In response to the Building (Earthquake-prone Buildings) Amendment Act 2016 and new building standard (NBS), some territorial authorities rapidly closed buildings with NBS ratings of less than 34%, pending their remediation or demolition.

When public buildings close, communities go without spaces to meet, socialise and access services, sometimes leading to negative impacts on social and economic wellbeing. Without clear policy on building closure that considers all the risk factors, it is difficult for decision makers to explain the rationale and gain community buy-in for their decisions.

What did BRANZ do?

Under the strategic pillar of Increasing resilience of the built environment, BRANZ led a Levy-funded research project to understand the decision-making processes to close or keep open earthquake-prone council buildings. BRANZ researchers and collaborators worked with several territorial authorities across New Zealand to understand who made the decisions, what the key drivers were and how engineering risk information was interpreted, evaluated and acted upon.

BRANZ co-designed a framework to help territorial authorities confidently and robustly make decisions on managing earthquake-prone council buildings that are in the best interests of their community.

The framework consists of five steps that generally align with the international standard for risk management (ISO 31000), stepping users through the risk identification, assessment and treatment phases of risk management.

Applying the framework, decision makers can weigh up multiple factors. These include the number of building occupants, the average time spent in the building and the duration the building will be earthquake-prone, along with the social and economic consequences of closure. This step is critical to ensure that territorial authorities are balancing both their responsibility under the Health and Safety at Work Act 2015 (HSWA) and their duties under the Local Government Act 2002 (LGA).

Outcomes

• Territorial authorities will have a decision-making framework to make decisions consistent with their various legislative obligations that can be clearly communicated to the public.
• Council officers, chief executives and elected members can have confidence on how to meet their legislative obligations under the Building (Earthquake-prone Buildings) Amendment Act, HSWA and LGA.

Working in collaboration

BRANZ acknowledges collaborators Resilient Organisations, Kestrel Group, the University of Canterbury LEAD Institute of Law, Emergencies and Disasters and Massey University Joint Centre for Disaster Research. Special thanks also goes to the several territorial authorities involved in the development, testing and refinement of the framework.

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