Engineer Studied Earthquake-Resistant Dams In Japan

Press, Volume CVI, Issue 31143, 20 August 1966, Page 25

Engineer Studied EarthquakeResistant Dams In Japan

Japanese research into the design of earthquake - resistant dams may help New Zealand engineering. Mr A. V. Hatrick, a Ministry of Works senior design engineer associated with the Aviemore scheme, has recently returned from a six-week tour of Japan. where he studied earthquake engineering, as applied to dam structures.

Japan has thousands of dams, some 900 years old. and the outstanding work of its engineers in the dam field is internationally recognised.; Conditions for building dams in New Zealand and Japan are similar. Mr Hatrick said that the Japanese had several ap-; proaches to earthquake engineering, as applied to dams. One widely practised was the installation of measuring instruments in dam structures and on their crests, and in the natural foundations. The instruments embedded in structures were connected to

I the surface by electrical! ; cables. ! The instruments enabled i the behaviour of the dams dwhen shaken by earthquakes . to be understood. Much could I be learned even from small detectable only - by sensitive instruments. In ■ •iJapan, as in New Zealand.: 1 . these occurred quite fre-; ! I qently. ■ Another approach was the >!use of vibrating machines on Hthe crests of dam structures Hto simulate earthquakes. II Laboratory Tests J Japanese engineers made

many models of projected dam structures in their laboratories and “shook'' them, and measured the reactions. The model technique was used because theoretical knowledge could not at present give all the answers. The same situation arose in hydraulics and the New Zealand Ministry of Works had long been using hydraulic models to study problems in harbour, hydroelectric and catchment schemes. Mr Hatrick said it was now almost routine practice in Japan, when construction of a dam was planned, first to install measuring instruments in the natural foundation and

record its behaviour during earthquakes as a means of forecasting the effects of earthquakes on the structure. Nearly all the concrete dams in Japan had been build in the last 30 years and, as far as Mr Hatrick was aware, none had suffered any serious damage from earthquakes. Most of these concrete dams were owned by electric power companies, which had their own central research institute in Tokyo. The sum of Japanese knowledge of concrete dams was considerable. Less was known about the

behaviour of earth dams, which comprised by far the greatest proportion of Japan s dams. They were, in the main, owned by local authorities which, while they had access to research establishments, appeared less financial than the electricity companies. Most of their dams were for flood control, irrigation or water supply purposes, said Mr Hatrick The behaviour of earth dams seemed to be more complex than that of concrete dams, so that research on them was not so far advanced. However, in the last few years study of these dams had been intensified and new knowledge was emerging all the time.