Research reduces earthquake strengthening costs for schools
Hon Nikki Kaye
Associate Minister of Education
20 October 2013
Media Statement
Research reduces earthquake strengthening costs for schools
Associate Education Minister Nikki
Kaye says ground-breaking research released today by the
Ministry of Education has found timber-framed classrooms are
extremely resilient to earthquakes.
“This is good
news for the education budget because we will not have to
spend hundreds of millions of dollars on earthquake
strengthening these buildings,” Ms Kaye says.
“The research has confirmed these buildings are
safe and resilient in quakes. This means that we can focus
on modernising buildings to provide better learning
environments.
“The Ministry advises me that
timber-framed structures account for up to 90 per cent of
school classroom and administration
buildings.
“Timber-framed school buildings
performed very well in the Canterbury earthquakes, with no
major structural damage caused by ground shaking. Building
damage there was caused by liquefaction, rather than
shaking.
“The Ministry advises me that this led
to commissioning research to find out definitively whether
wooden school buildings needed earthquake upgrading, or
whether they were already strong enough.
“This
research confirmed that timber-framed buildings are low risk
and don’t pose a significant life safety hazard in quakes.
But it showed that previous models which engineers worked
with didn’t accurately quantify this.
“As a
result of the research engineers are conservatively
assessing that the Ministry’s one and two-storey
timber-framed buildings are twice as strong as previously
thought.
“In terms of school buildings which are
not timber-framed, outside of greater Christchurch the
Ministry is looking more closely at a small group of 1900
out of a total 35,700 buildings to make more detailed
engineering assessments.
“These include
unreinforced masonry, multiple storey and heavy construction
buildings and buildings with a large open area. Based on the
individual assessments, they will be prioritised for
strengthening work if required.
“In greater
Christchurch the Ministry has been assessing approximately
2600 buildings as required by the Canterbury Earthquake
Recovery Authority (CERA). A majority of these buildings are
timber framed and CERA has agreed to a streamlined approach
to the evaluation of timber framed school buildings.
“This research may have wider implications for
the nation’s wooden buildings, meaning they are
significantly more resilient than engineering calculations
had previously suggested.”
The research –
Report on Structural Testing of a Standard Classroom
Block in Carterton in June 2013 - can be found at: http://www.minedu.govt.nz/DestructiveTesting
More
about the research
The Kestrel Group’s
Dave Brunsdon, a top private sector structural and
earthquake engineer, was appointed to head the Ministry of
Education’s Engineering Strategy Group in late 2012 to
co-ordinate the approach to assessments of the strength of
school buildings.
The group commissioned destructive
testing on a typical timber-framed classroom block,
literally attempting to pull it apart using two huge trucks
and cables. The massive force pulling in opposite directions
was designed to place the building under stresses it would
experience during an earthquake.
It was thought the
building might splinter when the massive [40-50 kN] of force
was applied. That’s what existing engineering models would
have predicted. But what was found was there was no real
damage until forces four or five times greater than the
building would have been predicted to withstand were
applied. At that point some windows broke. Even then, the
building continued on to withstand much higher levels of
loading without showing any signs of imminent
collapse.
The results from this testing are being
circulated in engineering circles and have been fed into the
Ministry of Business, Innovation and Employment’s current
review of the management of earthquake-prone buildings. It
is also being fed into the New Zealand Society for
Earthquake Engineering’s guidelines for the assessment of
buildings.
The research was independent and
externally reviewed. The test was undertaken by the Building
Research Association of New Zealand (BRANZ) on behalf of the
Ministry of
Education
ENDS