Earthquake-strengthening school buildings

Features 31 May 2012 Catholic schools in the Wellington and Palmerston North dioceses are generally in good shape although there are some school buildings in need of earthquake strengthening.Catholic Schools…


31 May 2012

Catholic schools in the Wellington and Palmerston North dioceses are generally in good shape although there are some school buildings in need of earthquake strengthening.
Catholic Schools Board Limited which looks after the 77 schools in the two dioceses is currently implementing a strengthening programme for the buildings that have been identified as high risk.

CSBL executive chair Gary Quirke says CSBL started investigating the seismic resilience of school buildings immediately after the first Canterbury quake on September 4, 2010. Now he says the biggest issue facing CSBL and proprietors will be funding the necessary strengthening work.

CSBL established a Structural Standards Committee to advise on the appropriate seismic standards for school buildings and to develop a process to quantify the risk. The committee includes structural engineer Adam Thornton who is also an adviser to the Royal Commission investigating the Canterbury earthquakes and the managing director of leading construction firm LT McGuiness Ltd, Brian McGuinness.

The committee first established criteria for determining whether school buildings were compliant with current seismic standards and for developing a methodology for speedily assessing all CSBL school buildings.

From a pilot study of four Wellington schools early last year, the committee produced a standard which recommended an acceptable minimum strength level for the continued occupation of buildings and timeframes for strengthening them depending on the assessed seismic strength of each.

In line with Ministry of Education requirements, CSBL has made a commitment to finish within three years strengthening buildings that pose an unacceptably high risk. This key recommendation has also been adopted by the Association of Proprietors of Integrated Schools.

CSBL has also developed a methodology for assessing the potential seismic risk of school buildings. The risk criteria includes the building age, construction, use, number of storeys, type of soil, earthquake zone and whether a building has been previously strengthened. Gary says many of our school buildings are of single-storey, timber frame construction which generally presents a lower risk in an earthquake compared to multi-storey buildings of heavy construction.

The initial risk assessment of all school buildings in the two dioceses was finished last October and CSBL has since established a programme which will see engineers making detailed assessments of every school over the next three years where relevant. A school’s priority on the detailed assessment programme has been determined by its overall rating obtained from the initial risk assessment.

Gary says CSBL will contact the proprietor of any school that fails to meet building standards and its board of trustees to agree on appropriate remedial action. The school property that CSBL manages on behalf of the proprietors in the two dioceses amounts to more than 500 school buildings.

Buildings can be classified as ‘earthquake-prone’ if they fail to meet one third (34%) of the seismic performance requirements of the current loadings code for new buildings.
The first building code requiring specific earthquake engineering considerations for buildings was introduced in 1935 following the 1931 Napier earthquake.

It was revised, with additional significant changes, in 1965, 1976, 1984, 1992 and 2004.
In particular, the 1965, 1976 and 2004 revisions made significant increases in lateral earthquake loadings and the 2004 building code also required local authorities to develop policies for identifying earthquake-prone-buildings within their local areas and to require the building owners to strengthen them within specified timeframes.