The 3 Elephants In The Room When It Comes To Seismic Design.

A blog entry from Managing Director, Matt Bishop.

This week, I was fortunate enough to speak at the AWCI ANZ National Conference in Uluru, where I addressed the three elephant(s) in the room when it comes to seismic design. 

Here are the three most commonly heard phrases from industry members when discussing seismic code and compliance in Australia; 

seismic design elephants in room

1. "We don't have earthquakes in Aus so seismic isn't a priority?" The geologists have done the research, and Australia DOES have earthquakes, just not as frequently as other parts of the world. MunichRE (the global insurance company) estimate a repeat of the 1957 Adelaide earthquake today would be a multi-billion dollar loss. So why is it so hard to collectively get our heads around this part of the building code? The answer is 'Present Bias'. It's how the mind works, we downrate risks in the future to the point that we say "that'll never happen". That's what we used to say in Christchurch before the 2011 earthquakes...

In short, seismic is in the contract because it's in the code and whilst Australia might have lower seismic risk compared to other countries, earthquakes of similar magnitude to the ones we experienced in NZ do occur in Australia. Despite being more lenient in the past, Aussie regulators and insurance companies are now focused on seismic compliance in an effort to bring the country up to international standards.

2. "Why are building elements not designed as “one element”, rather than three separate designs from three separate professionals? The simple answer is that engineers are great at specialising (knowing a lot about very little), and it just doesn't occur to anyone to design collaboratively. But from the contractor's point of view, it's the same wall and wouldn't it be best practice to get one coordinated design? The good news is that it can be done. The effective coordination of interior building elements is what we pride ourselves on at BVT. Our coordinated design approach reduces design costs, materials used and the amount of labour and time spent on site.

3. "Sounds expensive, who should pay for interior engineering?" Great question. The cost of non-structural building elements seismic design is approximately 2.5% of non-structural materials and labour. Due to the way the contractual obligations for interiors are passed down, this cost initially falls on the subcontractor. Seismic design responsibilities will typically transfer to the subcontractor through inclusion of a requirement like, "All construction to comply with current building code", or maybe more specifically "All interior building elements to comply with AS 1170.4". A broad contractual obligation like this leaves room for interpretation. But ultimately, what the regulator accepts as a compliant design will be good enough for the contract.

Over time, the sub-trades begin to include the seismic design as a provisional sum, and then it becomes part of the pre-tender design package. We see more and more of our engagements in NZ moving upstream now, however it did take 5 odd years for that occur. As seismic design becomes prevalent in the other Australian states, we will hopefully see a faster progression of costs upstream to where we can really make a difference through collaborative design processes.

When it comes to interior engineering and seismic design, our team are working hard to make it simpler. Understanding what the industry needs is a priority of ours and we are here to answer any questions you might have. I welcome you to get in touch with us.

- Matt Bishop.