Last year, the Palmerston North City Council released a list of Earthquake Prone Buildings. The list comprises mostly Unreinforced Masonry Buildings in the city centre and the buildings listed are below 33 per cent of what is required for new buildings. The Building Act 2004 defines buildings below 33 per cent of code as earthquake-prone and having greater risk of collapse in a moderate earthquake.
Peter Eathorne, general manger Customer Services, says the list was put together after an initial conservative assessment carried out by a consulting engineer on behalf of the Council and has been updated every few months since as more buildings are assessed.
The owners of the buildings on the list need to carry out their own structural integrity assessment or start planning for a strengthening programme. Since the original list was compiled several owners have provided structural engineering reports showing their buildings comply, others have carried out work to ensure their buildings meet code and these buildings have been removed from the list.
"Last year," Mr Eathorne says, "400 other buildings were prioritised based on high public use and emergency services buildings - These buildings are being assessed, a process which will take up to four years to complete."
Ray Swadel, general manager City Networks, says alongside this process Council has taken the proactive measure of carrying out initial assessments on its property portfolio, regardless of whether they are on the list or not.
This is the third update to the original list of the Earthquake Prone Buildings (EQPB) list. The list is compiled of 131 buildings, 13 of which are Council-owned, including:
Civic Administration Building:
- Central Tower Block, South West block
- Council Chambers
- North East Block including front of house
- Science Gallery
- Iwi Gallery
- McDairmid West Store
- Pitt St Workshop
Caccia Birch House
Mr Swadel says the Keith Street Power Station was added to the list last year and since then a detailed engineering evaluation has been carried out.
"The results are that Council, as the building owner, is not prepared to carry the risk of allowing members of the public to be in the building given its poor evaluation."
"The Power Station is an important building to this city and we are happy to review our decision if additional information comes to light. However, based on the information seen to date it has been decided to close the building."
On a more positive note, Mr Swadel says he is pleased to report both the Palmerston North City Central Library and the Regent Theatre have come through the initial assessment process very well and no further assessment for either building is required.
Last year, the Square Edge Building was added to the EQPB list. Council then carried out a detailed engineering evaluation which led to the rating of the building rising significantly. Mr Swadel says the initial report identified parts of the building to be 2 or 3 % of code, however, following an in-depth assessment the rating was found to be closer to the 33% of code. "This means the building has been confirmed as earthquake prone however the relative risk is significantly less."
Mr Swadel says Council staff are preparing a report on all EQPB Council-owned properties, including Square Edge and the Keith Street Power Station, which will be considered by elected members in due course.
The latest additions to the EQPB list include The Civic Administration Building. The initial assessment for the building is in three parts due to the size of its footprint. It found the performance of the five story building during an earthquake was subject to the ground that it sits on. Subsequently, a ground assessment was undertaken which found the ground to be better than thought. Now, a Detailed Engineering Evaluation that takes into account the new ground information is being undertaken.
Mr Swadel says the results of the report, due midyear, may see the building removed from the EQPB list. "Regardless of this, Council is committed to investigate and cost strengthening options which again will be presented to Councillors."
A number of buildings at Te Manawa have been added to the list. Mr Swadel says as these buildings are not unreinforced masonry buildings we anticipate that the Detailed Engineering Evaluation, which is now being undertaken, could well see these buildings removed from the list.
Caccia Birch has been added to the list. Mr Swadel says it's important to note here the initial assessment does not take into account what a building is made of even if, as in this case, it is made of wood, which performs better in an earthquake than most other structures. "Because of this, it's thought the rating will improve once the Detailed Engineering Evaluation, which is currently being carried out, is completed."
Council's current EQPB policy is in line with existing Government guidelines. Council currently requires a 15-30 year timeframe for strengthening buildings below 33% of new building code towards a minimum of 67% of code.
Policy planner Matthew Mackay says the guidelines are pre-Christchurch earthquakes. Earlier this year the Government consulted on a new draft policy developed post the recommendations from Canterbury Earthquake Royal Commission.
Matthew Mackay says Council runs a Heritage Fund to assist the owners of heritage buildings and to date 12 heritage building owners have received grants to assist with seismic engineering assessments.
The full EQPB list is available at: /yourcouncil/councilactivities/currentprojects/earthquake-prone-buildings-project/