Precautions Against Major Earthquakes In N.Z. Urged

Press, Volume CI, Issue 29748, 15 February 1962, Page 19

Precautions Against Major Earthquakes In N.Z. Urged

A single great earthquake could set back New Zealand’s economy for generations, Mr A. W. Smith, an Auckland architect, said yesterday. He was presenting a paper called “Some Aspects of Seismic Damage” at the annual conference of the New Zealand Institution of Engineers in Christchurch.

“It is clearly our duty to take whatever steps we can to reduce the toll of damage that a great earthquake might cause." said Mr Smith. “Our livelihood may depend upon our doing so.” New Zealand could not “afford’’ an earthquake such as the one that devastated Chile not so long ago. At present New Zealand’s Earthquake and War Damage account contained less than £23 million and was growing at the rate of some £2 million a year. “In the Chilean earthquakes, the damage was estimated at more than £175 million in a stricken zone some three-quarters of the area of New Zealand," Mr Smith said. If the fund was exhausted, the Earthquake and War Damage Act. 1944. required the Minister to borrow the money necessary to make up the deficiency after any disaster. Design Of Foundations Although the standard specification ensured that modern buildings had a considerable resistance to seismic damage, there was still room for considerable improvement. The code lacked any real reouirements for the design of foundations against seismic loadings and this was a major omission, said Mr Smith. There was a definite need for all glass larger than a specified size to be mounted in flexible packing to allow at least half an inch wracking of the frame before the glass fractured. Where continuous glazed facings were used, the glass should be carried by a separate structural sub-frame supported from the main building frame by flexible mountings. There should also be adequate structural verandas over any pavement capable of withstanding a sheet of 3-Bin glass falling 100 ft. Some existing verandas were more dangerous than the walls supporting them, and all new ones should be of reinforced concrete well anchored to the main building frame. Safest Position “The safest position in a building is usually under a stout doorway.” said Mr Smith. “If the code required all large buildings to be provided with a set-back entranceway or foyer, resistant to earthouake damage.

this would afford a valuable refuge.” Mr Smith also suggested that all large buildings should have an emergency room, near the main access, provided with first-aid kits, torches, crowbars, jacks, protective helmets and, perhaps, gas-cutting gear. “A major shock is likely to devastate a complete town, and it will be quite impossible to bring emergency gear into the stricken area quickly enough." he said. The real problem in reducing disaster damage lay in strengthening and securing existing old buildings, many of which had structural defects. decayed components, and inherent weaknesses, and which were highly hazardous to earthquakes. “Start Should Be Made” “Local bodies do not have the power, and there is no real legal requirement to have these buildings made damage resistant.” said Mr Smith. “Until another great earthquake occurs, there is probably no remedy But the hazards are so great that a start at least should be made “Local bodies must have clear powers to require the repair of structural defects and be able to condemn unsafe structures. The earthquake and fire damage insurance premiums should be based on a realistic rate schedule depending upon the assessed susceptibility to damage of each structure insured."

Mr Smith claimed that a structural survey of buildings would protect not only the owner and the insurance company in their contract, but also the third party who stood to get killed under the building during an earthquake. “In due course our courts may have to consider problems of negligence and damage responsibility,” he said. Theatres and Schools Cinemas, schools, theatres and halls, many of which were of “early settler” construction, were a special problem that should be tackled immediately. “If a maior shock hit a city such as Wellington between 8 p.m and 10 p.tn. on Saturday, there might be about 2000 casualties from the theatres alone.” said Mr Smith.

"Such buildings should be critically inspected by the local body every two or three years. Even our finest buildings decay and deteriorate without ceaseless vigilance and proper maintenance. It should not be possible to pack more than 1000 persons into a building of unknown stability,” he said. In the average New Zealand timber house, the only real hazards during a moderate earthquake were chimney collapse and fire. Under strong earthquakes, however, there were other features in houses that were unsatisfactory.