'Huge uncertainty' in building design
MARC GREENHILL Last updated 12:15 12/03/2012

STRUCTURAL ENGINEER: Richard Sharpe says buildings are never "earthquake-proof".

Christchurch Earthquake 2011 Rules on green-blue homes delayed Big crowds for grand old lady's wake Cathedral debate canned Japanese, NZ scientists collaborate on quakes Lawyers fear court will never reopen Owners forced to risk rockfall Canterbury quake recovery boss pleased with pace of progress Thousands farewell cathedral Japanese scientists view quake damage Cera, scientists agog at studies; residents less than impressed
Engineers should be proud of their efforts in the development of Christchurch's earthquake design standards, an inquiry has heard.

New technology to be used in the rebuild of the central city is today being heard by the Canterbury earthquakes royal commission.

The three-day hearing will focus on the range of new building technologies relevant to the quake-damaged central business district and other New Zealand regions.

Structural engineer Richard Sharpe, of Beca in Wellington, told commissioners there was "always room for improvement", but engineers had "a lot to be extremely proud of".

There was a "huge amount of uncertainty" in the development of quake design loads, and quake engineering was "as much an art as it is a science", he said.

Buildings were never "earthquake-proof", Sharpe said.

"I believe our design philosophies acknowledge that there's always a chance that a properly designed, properly constructed structure will still collapse in an earthquake." he said.

"All our material properties, our understanding of the earthquake - everything that goes into it - has some probability of being not what you thought it was going to be."

Commission chairman Justice Mark Cooper said the hearing was a chance to "look positively into the future".

The hearing will be a platform for a constructive debate about building design philosophies, such as "life safety" versus "building survivability", and the associated economic impacts.

It will also discuss new building technologies, some of which are already being implemented in New Zealand, and others that are emerging.

Presenters will include academics, senior practising engineers and professional engineering organizations.


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Have also included the full report so that you can see the 20 comments made re building on a swamp - which is what  Christchurch is.  Underground streams etc which is available for viewing at the Museum I think it is in what they call the "Black maps".  Done by the surveyors who came out from England in about the 1800's to survey for a city to be built. Yes some buildings did have to have pumps going in their basements to pump water out particularly when their was a high tide.  I even worked in one in the 1950's down Hereford Street. 
Where we live in the West of the City it is definitely more stable being old Waimakariri river bed -stoney not boggy and certainly not susceptible to liquefaction like in the East or around the river banks.
One person in St Martins had to replace the piles of his house and had to go down 17 meters to strike more solid ground and cost him a small fortune.
They will have to think seriously as to how tall a building is allowed to be rebuilt in the central city and also the building codes will have to be very very high for rebuilding in Christchurch.