EARTHQUAKE SHOCKS.

Auckland Star, Volume LX, Issue 303, 23 December 1929, Page 8

EARTHQUAKE SHOCKS.

LESSONS OF SOUTH ISLAND TREMORS. .

ARCHITECTS' HEPORT.

MINIMISING FUTURE DAMAGE. 1

Little thought was given in the earthquake striken areas of the South Island to designing and erecting buildings to resist tremors of the magnitude that were experienced, according "t 0 -the special committee of the New Zealand Institute of Architects, June to study features of the disaster and make recommendations eoncenuno them.

The committee) which- consisted of Mr. C. E. Foid, architect, of Auckland Mr. H. Butcher, architect' and townplanner to the Wellington City Council and Mr. A. S. Mitchell, architect and engineer, of Wellington, recorded the opinion (a) "That the damaged buildings examined showed that little thought had been given in their design and erection to the possibilities of earthquake shock. Had this thought been giy eu the loss sustained would have been vertf largely minimised, even with the knon£ ledge generally available at the times the buildings, were erected.

"(b) That if the information upon the subject available to-day is applied with skill and knowledge in the desi<m and construction of new buildings, then these buildings can be made highly earthquake —resisting at no great additional cost above that of ordinary sound construction for static conditions. In many case it is more a matter of application of the proper principles than o£ any additional cost."

Study of Movement Urged. In view of the fact that 2\few Zealand wae given to seismic activity, the committee suggests the urging upon members of the institute the need of making themeelves familiar with, the nature of earthquake movements, and the' principles of earthquake -resisting construction in order that they may giy& the necessary lead to the building public, and so retain public confidence. Publia safety further required that as far as possible the lessons learned in the recent earthquake shocks' should be embodied in building by-laws. On "tie other hand, the committee cautions,, oven the most effective by-laws cannot provide for all conditions, as every building offered problems which only proper technical skill and knowledge can solve with safety. The committee eliminated reference to frames structures, and suggested that a permanent committee should be get up to make a report upon such buildings based upon the evidence obtained in earthquakes In other countries and upon experimental investigation.

Iα making observations contenting the various types of buildings, the report adds, that wooden structures, well and solidly built, would withstand an earthquake shock very well, although there were one or two points that had to be considered. Frequently the founda-' tions of wooden buildings were inadequate. In Murchison- particularly •it had been noticed that buildings had shifted upon the wood piles supporting them, and in some cases the piles themselves had been pushed over'. A continuous foundation reinforced in some simple way was certainly advisable, even in a single-storey wooden house.

Dangers of Plaster. Lath and plaster were quite unsuitable for earthquake conditions, and should be replaced by fibrous plaster sheets very securely fixed, especially in ceilings. The earthquakes had brought down lath and plaster every where, "and it was only by good fortune that injury or loss of life had not been, suffered as a result. The fact that chimneys in seme cases were free to move where ay emerged from the roof had helped to prevent many from falling. It was clear that brick chimneys should be erected absolutely free of the wooden structure at every point, the committee added in recommending a designing of house requiring chimneys of low height only. Turning its attention to dwellings of brick, stone or concrete, with bearing walls, the committee points out that it is imperative that consideration of the forces to be resisted should be ?iven at. the outset. Owing to the impossibility of vertical reinforcement, buildings constructed of any small units such as bricks or concrete blocks, should be limited in height. There was a growing conviction that buildings of this design should be limited to two storeys. Foundations should be carried to an adequate depth and be of concrete properly reinforced. The importance of continuity not only to outer walls, but also across the buildings, could not be over-emphasised. A few extra pounds spent in the foundations would, in the event of an earthquake, bring a very full reward. The committee goes on to explain that its observations supported the views expressed after other investigations, and demonstrated that the most essential factor m _ making a building earthquakeresisting was the tying together of the component parts in an effective manner.