What do the three little pigs, a multiple car crash pile up and community earthquake resilience have in common?
Professor Michel Bruneau, Structural Engineer from the University of California in Berkeley, USA had some powerful analogies to describe earthquake community resilience during his recent presentation at the University of Canterbury (UC).
In collaboration with the UC Quake Centre, Professor Bruneau spent six weeks in Christchurch researching and analysing building damage in the CBD following the Canterbury earthquake sequence of 2010-2011.
Professor Bruneau says, “arguably the number one structural earthquake engineering dilemma is that most people don’t see resilient infrastructure as a priority until after a disaster. It’s simply human nature.”
Having experienced the devastation of earthquakes, Christchurch as a population now knows the importance of community resilience planning, but the majority of people globally are still in a ‘before the disaster’ mentality.
“Picture the three little pigs,” says Professor Bruneau. “As earthquake engineers we like to plan for a disaster by building a strong, robust infrastructure, one that is built to life-saving earthquake design codes (a house of bricks and mortar). One that will stay standing if a big, bad wolf (a disaster) were to come a-knocking.”
“But in reality the majority of people naturally have a mentality more like the little pigs that choose to build a house of straw. Straw is cheaper right now and there’s the possibility that the wolf may never come. This way you can use your time, resources and money doing other more enjoyable things than disaster resilience preparedness and have a much more fun and carefree life.”
It’s the pay now or pay later decision.
Even with current earthquake building code designs implemented in modern, developed cities throughout the world and therefore a sense that we are as prepared as we can be for an impending earthquake – there is another problem that still exists.
Professor Bruneau uses the analogy of a car crash to describe the problem.
For those people who have a car, law requires that car to meet certain ‘safe roadworthy standards.’ Drivers know the car will provide a degree of safety if there were to be an accident and most people will have insurance in place to cover the cost if any damage occurred.
The problem though, and what’s sometimes forgotten with implementing building codes, is that during a disaster - like an earthquake - everyone gets into the ‘accident’ at exactly the same time. We have a multiple car collision on our hands with a massive amount of damage, everyone is stuck in that pile up with nowhere to go and we all have to try and live with the consequences.
“We happen to know this very well here in Christchurch, where all the cars (buildings) got damaged at the same time and many people were stuck in a city and suburban ‘pile up’ (the no-go red zones) and had to live with it,” says Professor Bruneau.
Professor Bruneau goes on to say that, “the international community was not aware that the red zone remained the situation for so long. The news at the time broadcast that two buildings had collapsed and showed footage of the extent and scale of the damage. But most people wouldn’t have been aware that two years later (although smaller) the red zone was still in place and that the city remained closed for business.”
And for a city closed for so long, further damage continues to occur in already compromised buildings through exposure to the elements (think the Christchurch Cathedral). The damage grows as other urban elements and infrastructure such as footpaths, paving or signage deteriorate and fall further into disrepair.
Six years on from the initial damaging earthquakes that rocked Christchurch to its core, the city is still hugely affected by the consequences of these major events.
Professor Bruneau’s analogies really help to put these ideas into context.
We now know all too well that buildings with a ‘house made of straw’ mentality didn’t stand up to the huff and puff of an earthquake shudder as well as the stronger (designed to earthquake code) ‘house made of brick’ alternatives.
‘Crashed cars’ have slowly been pulled one by one from the wreckage, and either flattened or repaired. Roads slowly open up to allow drivers through again. Christchurch is slowly but surely rebuilding but has by no means achieved full pre-quake functionality and there’s still a long way to go.
We are keenly aware of the time it takes to recover after an event of this scale. We won't easily forget the consequences that such a major natural disaster brings to a city but we can take heart that lessons learnt may help other communities to better prepare for the worst.