ANTI-EARTHQUAKE

Evening Star, Issue 19804, 1 March 1928, Page 13

ANTI-EARTHQUAKE

METHODS ADOPTED IN JAPAN Wiliiin a leu- years, the mailer of protection against earthquake effects lias become decidedly prominent (says an editorial writer in the ‘ Engineering Nows Record,’ New York). Engineers, owners, financiers, and insurance men have all given the subject such attention as limited knowledge permits, and this concern is increasing rapidly. There is no longer much chance lor doubt, the writer concludes, as to tho possible effect of severe earthquake disturbances, since the large-scale demonstrations in Japan and those in San Francisco and Santa Barbara. Fairly definite conclusions may be reached as to the destructive effects on modern life and the necessary construction in tho case of such disturbances. Little corn fort - can. —be obtained from experience, for the few decades since modem buildings, pipe-lino systems, liowcr plants, and the like came into existence are short compared to tho long chapters of earthquake history. The concern which the problem baa aroused is, therefore, quite natural. He goes on:— “ One thing reasonably certain is that present building practice is far from strong enough to give much security in a strong earthquake. With this conviction, however, many havo come to believe that earthquakeresistant building is quite impossible. Tho lack of precedent in carthquakc-rcsistant-construction, and the widespread—it might almost bo called universal—extent of destruction in violent earthquakes lends some support to such pessimism. But probably a truer statement of tho present fact would bo to say that earthquake-resistant construction still remains to he developed.'

The writer then tells us of an attempt to solve this problem in the erection of a new hank building at Tokio:—“ln Japan, the problem of building fur safety against earthquakes is being attacked with determination, Measurements of earthquake motions and estimates of the forces _ involved lead to the conclusion that it is possible to obtain, if not complete security, at least a high degree of protection against even very violent earthquakes. The most interesting example of the results of this determination is described this week by tho designers. It is the frame for a large, heavy, ornamental bank structure now under erection in Tokio. It represents, bn the basis both of the Japanese estimates of requirements and the American engineers’ study ol structural possibilities, an adequate solution of the problem of protecting this very important building. In order to meet the needs of the ease it 'was necessary to go well outside the range of current practice in steelfiame construction. An ingenious new form of column was developed, very heavy and rigidly connected girder systems, were designed, and due recognition was given to the controlling influences of distortion bonding m these members by making them heaviest near the joints and lightest towards the centre.”

On the score of cost, not much is known as yot in this new field. The Mitsui building, however, would appear to involve no staggering excess for its earthquake protection. The writer understands that the total steel requirement is something more than twice that of a building designed under ordinary standards; and if wo take the cost of the framework of an ordinary building as 10 per cent, of the total cost, it would mean that the cost of this building has been increased 10 or lo per cent, by the ' earthquake provisions. Perhaps tho addition will be somewhat larger if corresponding precautions in the masonry and other e'ements of the structure are taken into account. This gives definite encouragement fur the belief that earthquake construction is not only practicable, but that it involves no prohibitive expense.