Gordon Campbell | Parliament TV | Parliament Today | News Video | Crime | Employers | Housing | Immigration | Legal | Local Govt. | Maori | Welfare | Unions | Youth | Search

 


Research Launched To Help Homes Better Withstand Earthquakes

Research Launched To Help Homes Better Withstand Earthquakes

A key research project, to help improve the resilience of the types of homes that performed poorly in the Christchurch earthquakes, has been launched.


Engineering experts from BRANZ, with research support from EQC, will use computer modelling to assess the impact of simulated seismic action on modern homes with more complex configurations.


The research has been prompted by findings that less complex homes in Christchurch performed better in the quakes than those built beyond the limits of New Zealand Standard 3604.


Variation in the stiffness of the bracing systems in a house is a common occurrence in such homes, especially hillside houses or older houses, which have been altered to make them more open plan.


The experts will examine how the bracing systems of different stiffness interact during a seismic event.


BRANZ and EQC expect the learnings from the research will be used to develop new guidelines for houses built outside the scope of NZS 3604 in order to mitigate the potential damage in earthquake events.


Project leader Angela Liu, a member of the BRANZ team which inspected residential properties for damage in Christchurch, said that one common phenomenon observed during the Canterbury earthquake sequence was the damage at the junctions where bracing systems changed or where the layout of the building changed.


“We found that many older buildings, pre-NZS 3604 Standard light timber framed houses with small windows and smaller rooms, had performed better than many modern buildings with complex seismic resisting systems,” said Ms Liu.


“The team observed more severe earthquake damage in homes which often had a mixture of different seismic resisting systems, either because of the presence of bigger rooms at one end of the dwelling or larger windows included on one side for a better view.


“According to the current regulations, seismic design of buildings mainly focuses on preserving life and our residential houses performed very well in this regard, as observed in Canterbury earthquake sequence.


“Builders and designers are guided by the prescriptive standard, NZ 3604 Timber Framed Buildings unless architectural and structural designers are employed. Bracing elements as per NZS 3604: 2011 are often sheathed timber walls.”


Ms Liu said that nowadays many people want bigger spacing between bracing lines so they can have bigger rooms or windows and, quite commonly, the spacing of bracing lines becomes too large to comply with NZS 3604.


“The designer will bring in an engineer to design just that part of the house and often the engineer will design a specific bracing system, which is almost definitely not sheathed light timber walls as introduced in NZS 3604.


“Or an owner may want to take out supporting walls in an older house to make larger rooms or an open plan living area and the engineer may, for instance, recommend installing a steel portal to brace that wider space.


“Currently, it appears there is often a mismatch between the mixed stiffness bracing elements resulting in some parts of the house moving more than others in an earthquake. We repeatedly found that cracking had appeared at the points where the stiffer and the more flexible bracing met. We also found that the more flexible bracing associated with the desire to take advantage of the view resulted in significant cladding and window damage to the extent that the dwelling was uninhabitable.”


The team also observed cracking in extensions, at the junctions between pre-1978 suspended timber piles and modern concrete slab floors and noted similar problems with houses which had been built on different levels down hillsides.


“We are aiming to find better ways to improve the performance of these more complex houses,” said Ms Liu.


”We will be looking at what the action is in individual areas and the computer model will allow us to adapt the bracing elements to ensure all the elements of bracing work together.


“That will enable us to provide guidance around areas where engineers need to pay more attention in future designs in order to mitigate problems associated with the potential differences in stiffness between the specifically designed bracing elements and NZ 3604 bracing elements.”


Ends

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

 

PARLIAMENT TODAY:

  • Week in Parliament 22-05-15
  • Saturday Sitting
  • House Rises At Midnight
  • Telco Levy Bill Passes
  • Telco Levy Bill Completes First Reading
  • Social Housing Bill Passes Under Urgency

  • TPPA: University Of Auckland Warns Of Negative TPP Impact

    The University of Auckland May 20, 2015 University of Auckland Warns of Negative TPP Impact With the Trans Pacific Partnership (TPP) negotiation drawing to a close, the University of Auckland has expressed serious concerns about its potential implications. ... More>>

    NZ Flag: Flag Referendum Gets Hit Hard In New Poll

    The latest Campbell Live text poll confirms it is time for the Prime Minister to listen to the public and shelve his flag referendum, says the New Zealand First Leader Rt Hon Winston Peters. More>>

    Gordon Campbell: The Government’s Belated Moves On Property Speculation

    Is it a property tax on capital gains or a capital gains tax on property? The Jesuitical distinctions in the government’s spin about its latest moves on property speculators are all about whether the government can claim that it jumped, or confess that it ... More>>

    Grant Robertson:
    Key Can’t Just Be Prime Minister For Parnell

    John Key must show New Zealanders in next week’s Budget that he is more than the Prime Minister for Parnell, and is also the Prime Minister for Pine Hill, Putararu and Palmerston North, Labour’s Finance spokesperson Grant Robertson says. In a ... More>>

    Labour Party: More Regional Jobs Go In Corrections Reshape

    News that 194 Corrections staff are to lose their jobs will have ramifications not only for them and their families but for the wider community, Labour’s Corrections spokesperson Kelvin Davis says. Prison units at Waikeria, Tongariro and Rimutaka ... More>>

    ALSO:

  • NZ First - Prison Job Losses to Send Money Offshore
  • TPPA: ‘Team Obama’ Regroups On Fast Track, Still Not Deliverable

    ‘After yesterday’s stinging and unexpected defeat for the Obama administration’s attempt to advance Fast Track legislation in the US Senate, Senate leaders have worked up a compromise they think will get them past this blockage’, according to Auckland ... More>>

    NZ Government: 5,500 More Doctors And Nurses In Our Hospitals

    Health Minister Jonathan Coleman says a record number of doctors and nurses are working in District Health Boards across the country. More>>

    Controller and Auditor General: Katherine Rich Conflict of Interest Decision

    We are writing to you about a matter that has been raised with us by members of the public. More>>

    ALSO:


    Budget 2015: Andrew Little On The 2015 Budget

    Speaking to the Chamber of Commerce, the Labour opposition leader attacked the government’s approach to economic issues facing New Zealand. He said they have been “more than reckless in their complacency” and “the next week’s budget will do nothing ... More>>

    Defence Force: NZDF Building Partner Capacity Mission Personnel In Iraq

    NZDF Building Partner Capacity Mission Personnel in Iraq The New Zealand Defence Force Building Partner Capacity training mission contingent is in place at Taji Military Complex in Iraq. The Chief of Defence Force Lieutenant General Tim Keating says the ... More>>

    PM Press Conference: ACC Levy Cuts Announced

    In a press conference this afternoon in Wellington, ACC Minister Nikki Kaye proposed $500 million worth of ACC levy cuts. More>>

    Quakes: New Process For Red Zone Crown Offers

    Canterbury Earthquake Recovery Minister Gerry Brownlee has announced a process to give everyone a say on the Crown offers to owners of vacant, commercial/industrial and uninsured properties in the Residential Red Zone. More>>

    ALSO:

    Gordon Campbell: On The Battle Obama Is Waging Over The TPP

    For the past two and a half years, this column has been arguing that the fate of the Trans Pacific Partnership (TPP) deal will hinge on whether US President Barack Obama can win Trade Promotion Authority (TPA) from Congress... Last week, the White House finally, finally unveiled a draft TPA Bill. More>>

    ALSO:


    Gordon Campbell: On lessons for Labour from the UK election
    If the polls were right – and the pollsters kept telling us how accurate they’d been in 2010, and even Nate Silver was getting the same results – there seemed no way that the British Labour Party could lose last Thursday’s British election. With Labour predicted to win around 270 seats and the Scottish National Party batting around 55-60 seats, Labour seemed to be home free. But…as we now know, things didn’t turn out that way. Labour ended up with 232 seats and the Conservatives swept back to power with an outright majority, after winning only a little more than a third ( 36.9%) of the votes cast.MORE >>
    Also.

  • NZ PM John Key - PM congratulates David Cameron after UK election
  • The Nation IV Transcript - Hack Attack author Nick Davies
  • Get More From Scoop

     

    LATEST HEADLINES

     
     
     
     
     
    More RSS  RSS
     
     
     
     
    Politics
    Search Scoop  
     
     
    Powered by Vodafone
    NZ independent news