More Buildings Evaluated Against Earthquake Standards

About 100 public and Council buildings and structures have now had initial evaluations for how well they would stand up to an earthquake.

The Kaitake Community Board will on Monday (2 July) be the first Council body to receive a report on the progress NPDC is making on evaluating the performance of public buildings in an earthquake against the requirements set out in the Building Code’s standard for new buildings.

“These initial evaluations are the first indication of how well a building meets current building standards,” says Manager Customer and Regulatory Services Simon Pickford.

“Buildings that we have identified as possibly meeting less than a third of the current standard aren’t definitely earthquake-prone, but are likely to be. Our initial evaluations mean that these buildings need to be looked at more closely by engineers so that their seismic strength can be properly determined.”

The Building Act states an earthquake-prone building has less than one-third of the seismic bracing strength required of a new building designed to current codes, and so is considered unacceptably unsafe in a moderate earthquake.

NPDC’s initial desktop review and evaluations grade buildings from A to E. E-grade buildings have been assessed as probably meeting less than 20 per cent of the new building standard, and D-grade buildings between 20 and 33 per cent.

“The owners of those buildings have a specific timeframe, depending on the risk posed by each building, to carry out a detailed structural assessment to confirm the status of their buildings,” says Mr Pickford.

All buildings (other than detached residential, and approximating 1,500) will or have been evaluated as to whether they require an engineer’s assessment. About 200 of these require an initial evaluation process (IEP), of which about 100 have been completed so far.

Of the completed IEPs, 13 buildings have been graded D or E, and 30 have been grade A or A+ (meeting from 81 per cent to more than 100 per cent of the current standard).

Ten of those graded D or E are school buildings, one is a church and one a commercial premise. Number 13 on the list, the Opera House part of TSB Showplace, has been graded D, as announced in May.

All schools in the district have been reviewed and only those with potential issues are listed in the Council’s earthquake-prone buildings schedule. The Ministry of Education is advising schools about the earthquake assessments.

Taranaki Base Hospital has had 37 buildings reviewed, all of which rated between A+ and C and require no further assessment under the current policy.

The district’s 17 water reservoirs have been assessed as unlikely to be earthquake-prone.

Detailed structural assessments are to be done on the Opera House and Govett-Brewster Art Gallery (rated C), with further assessments on Oakura Town Hall, Inglewood Town Hall and Puke Ariki’s South Wing (all rated C) to identify the feasibility of bringing them up to 67 per cent of the current building standards.

The New Zealand Society for Earthquake Engineering recommends that buildings should meet 67 per cent or more of the new building standard. The Council’s policy is to encourage owners to strengthen their buildings to this level.

Earthquake-prone building grades

A+: Meets more than 100 per cent of the Building Act’s new building standard, and so is unlikely to be an earthquake-prone building (EPB). No further assessment required.
A: 81 to 100 per cent. Unlikely to be EPB. No further assessment required.
B: 68 to 80 per cent. Unlikely to be EPB. No further assessment required.
C: 34 to 67 per cent. Depending on the percentage, a detailed assessment may be required.
D: 20 to 33 per cent. Likely to be EPB, subject to detailed assessment.
E: Less than 20 per cent. Likely to be EPB, subject to detailed assessment.