Has the risk of earthquakes been overestimated in New Zealand? The Christchurch earthquakes of
2010 and 2011 put a huge toll on the people of Christchurch but also a burden
for the rest of New Zealand. The
question remains – “Are we now going too far to protect the lives of our people
in future events? Can we afford the
The current Building Act of 2004 has a policy for Earthquake
Prone Buildings (EPB’s). Each individual
council is required to have a policy for identifying and dealing with buildings
defined as earthquake prone. The minimum
standard is specified as 33% of New Buildings Standard (% NBS). That correlates to the strength 1/3 of the
strength of a building built today to current building standards. Most councils have taken 33% NBS as the
minimum standard for giving differing time periods for owners to either
strengthen their building or demolish to remove the hazard.
Regulators are currently preparing legislation to amend the Building
Act with the EPB provisions likely to be amended. It is likely that the new legislation will
become more stringent and involve tighter timeframes and impose more cost onto
commercial building owners. This will
come at a massive cost. Estimates are
there are over 1000 EPB’s in Auckland alone with an estimated cost of over $500M
to strengthen. With many of these buildings
either outside the CPD of cities in suburbs such as Mt Eden, Balmoral, Te Aro or
in provincial New Zealand towns such as Oamaru, Gisborne, Whakatane and Rotorua
(to name a few) where rental returns are low and the cost of strengthening is
uneconomic, where does this leave the future of these areas?
New Zealand needs its heritage and our buildings to define
who we are, the struggles we have faced to forge our nation and we owe it to
our forbearers to save the best examples for future generations to enjoy.
I believe that over the next 10 years we will see a huge
change in our towns and cities. Substandard
heritage buildings with no heritage merit will disappear and will be replaced
with modern structures that better cater for 21st century
lifestyles. A selection of heritage
structures that either have architectural, or cultural merit or have historical
significance will be retained and bought up to a good standard. The government needs to consider ways to ease
the pain for owners of these buildings with one option being tax breaks for
commercial property owners completing seismic strengthening.
The risk of injury in earthquakes needs to be put into
perspective. With only two major
earthquakes in New Zealand causing deaths in the past 100 years (Napier 1933
and Christchurch 2011) is the billions of dollars required to deal with the
issue worth the investment? Should
market forces be left to determine what level of compliance is right for the
safety of our people?
This thought leadership article is by Andrew Thompson, the Structural Engineering Manager at Harrison Grierson.
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