Resilience in the built environment – a necessity for the future

By - , Build 206

Aotearoa New Zealand’s built environment is under pressure to respond to modern needs and societal expectations, says Paul Campbell, National Technical Leader – Building Structures, WSP.

B206 Paul Campbell
B206 Paul Campbell

In an era of rapid urbanisation, climate change and increasing natural disasters, resilience has become increasingly critical.

The Resilient Buildings Project showed there is a shortfall between societal performance expectations and what the New Zealand Building Code delivers – it’s time to critically review our resilience.

Resilience is often defined as the ability of buildings, infrastructure and communities to withstand, adapt to and recover from adverse events.

Importantly, resilience needs to consider the built environment and people and communities. It’s not just about surviving disasters – it’s about thriving in the face of challenges.

The hazards we face

New Zealand’s unique geography means earthquakes, tsunamis, flooding, volcanic activity and other natural hazards can happen at any time. Within each of these hazards, there is a spectrum of severity. The government discussion document Strengthening New Zealand’s emergency management legislation laid out the 50-year likelihood of various potential natural disasters. Examples include the most likely being a Cyclone Gabrielle-equivalent event (80%) or a magnitude 8 Alpine Fault earthquake (75%) through to less likely events such as a large Taranaki eruption (1%) and a magnitude 9.1 Hikurangi subduction zone earthquake (1%).

What the New Zealand regulatory system delivers

The New Zealand Building Code is performance based and primarily focused on life safety with a basic level of amenity rather than comprehensive asset protection and resilience. The Code sets a legal minimum performance, yet it is often treated as a premium standard to be achieved. Consumers and designers can choose to do better than Code minimum. Resources like Low damage seismic design and Earthquake design for uncertainty give designers advice when going above Code minimum.

The power of individual choice

Small resilience choices we make individually contribute significantly to social and community resilience. Whether it’s choosing a simple repairable layout, choosing lightweight cladding to decrease seismic weight or making your foundation system able to be relevelled, these decisions add up to create a more resilient built environment.

Enhancing the resilience of existing buildings is more challenging but achievable. Restraining water tanks, adding additional bracing to the subfloor or choosing resilient materials such as flexible vinyl over rigid tiles make a difference.

The crucial step individuals can take is to understand what performance they want versus what the regulations require and make informed decisions of Code or above-Code performance.

Affordability of resilience

Housing affordability in Aotearoa is an issue. Getting reliable cost information for designing beyond Code is difficult. US studies indicate that the cost premium for seismic resilience is low and that a 50% increase adds an estimated 0–2% to cost, depending on building type. A New Zealand study found the premium was 0.5–1.5%. Some resilience enhancements such as simplifying building form may be cost neutral or even a saving.

The future of resilience

As we face future challenges of climate change, population growth and housing densification with an ageing built environment, we will need innovative and adaptive strategies. You have the choice on your next project to make informed Code versus beyond-Code performance decisions. You may choose not to design for the extremely rare event, but imagine if we all designed for the more common events to cause less damage.

We all have the power to influence a more resilient future.

Download the PDF

More articles about these topics

Articles are correct at the time of publication but may have since become outdated.

B206 Paul Campbell
B206 Paul Campbell

Advertisement

Advertisement