| Shunzo Okamoto, PhD |
 Dr. Shunzo OKAMOTO, Emeritus Professor at the University of Tokyo, was a pioneer among earthquake engineers in Japan. He had devoted his time and effort to the establishment of a firm foundation for structural and geotechnical earthquake engineering. His early professional life was spent in search for a rational approach to the evaluation of the dynamic earthquake resistance of a variety of soil-structure systems. Dr. Okamoto's writings contain important contributions on a number of topics regarding dams, tunnels, bridges and the other civil engineering structures. His first outstanding achievement is found in his paper entitled gAnalysis of frame structure vibration on the basis of the theorem of four moments (1939). The method described in this paper was a truly great breakthrough in simplifying the analysis of vibrating frame structures, and was put, with the later rapid development of computers, to great practical use. In the 1949 paper entitled gEstimation of strength or cylindrical hollowh, Dr. Okamoto clarified the stress distribution in the vicinity of a cylindrical hollow in an elastic medium in the gravitational field and presented a guideline for evaluating tunnel stability. This paper was awarded the Best Journal Paper Prize of 1949 by the Japan Society of Civil Engineers JSCE. Dr. Okamoto also developed theories for the dynamic behaviors of thin|walled cylinders, a most important influence on the later rapid increase in studies on storage tanks. Following this work on thin-walled structures, he expanded its application to the analysis of the dynamic behaviors of arch dams. At that time in Japan, the question of whether an arch dam could sustain considerable seismic loading was a matter, of great concern, and his findings and theories have allowed huge arch dams to be effectively designed and constructed in Japan. Dr. Okamoto had glearn from failuresh as his motto, and has actually made frequent investigative trips to see with his own eyes, failures caused by devastating events like the Fukui Earthquake of 1948 and the San Fernando Earthquake of 1972. On these occasions, he has repeatedly shown his valuable ability to quickly identify the most important components of a complex phenomenon. Through these investigations, Dr. Okamoto discovered that underground structures follow closely the motion of soils surrounding them, and thus, unlike structures on the surface are more liable to be damaged on the boundaries between soft and stiff soils. This important knowledge, its validity supported by a plethora of data from long-term earthquake observations, is now reflected in the updated design codes for tunnels and buried pipes. Dr. Okamoto was the first person to develop a seismometer including an automatic triggering device; this 1955 seismometer was the prototype on which many of the later strong-motion Seismometers were based. He also developed water-proof seismometers for underground use. These innovative seismometers have been improved continuously, and have been used at many different Sites including the Kurobe and Tagokura dams. The Kurobe dam, with a planned height of 186 m, was one of the largest arch dams ever attempted at the time, and the experience, knowledge and technology acquired from it has proved invaluable. The data from seismometers, together with the other physical quantities measured at Kurobe were summarized on one volume in gStatic and Dynamic Behavior of Kurobe Damh (Univ. of Tokyo Press, 1983) His great ability had been shown in the development of experimental methods for many different problems regarding suspension bridges, arch dams, earth and rock fill dams, buried pipes and tunnels. Among these, his experimental method for the study of dynamic arch dam-abutment-water interaction is worth-mentioning. Using a number of electro-magnetic actuators rather than a shaking table, equivalent inertia forces were applied on the concave downstream face of dam model holding back water. Various ingenious contrivances in this method led to the later development of hybrid experimental methodology. Professor Okamoto had devoted considerable effort to collecting all of his theoretical and experimental findings together for the benefit of later generations. These efforts were finally rewarded with the publication in the 1973 of his famous book, g Introduction to Earthquake Engineeringh (Univ. of Tokyo Press, 1984), which is now widely regarded as one of the most comprehensive and systematized introduction to earthquake engineering in Japan. This book has been awarded the Prize of the best international publication by the Japanese Ministry of Foreign Affairs. Dr Okamoto had a proud record of service in various organizations in Japan. In his capacity as chairman of the JSCE committees of Earthquake Engineering, Rock Mechanics and Long Spanned Suspension Bridges he has worked tirelessly to put to practical use both his own distinguished research achievements, as well as those of the many leading researchers inspired by him. He served as Vice President of the JSCE from 1962 and as President from 1972 to 1974. Dr. Okamoto has been a very active consultant and has participated in many important jobs for the advisory Committees of the Prime Ministerfs Office and of the Science and Technology Agency of Japan devoted to the mitigation of seismic hazards. Dr. Okamoto had also been active on the international stage. He has been involved in steering the International Association for Earthquake Engineering (IAEE) since its foundation. He served as a member of its executive board from 1969, and was nominated as an honorary member in 1980. During his career in IAEE, he has made great contributions to UNESCO activities. He investigated the damage to the Koyna dam, India, caused by the Koyna Earthquake of l967, as leader of the UNESCO reconnaissance team, and presented a clear explanation of its cause. Immediately after this investigation, Dr. Okamoto became IAEE representative member of the UNESCO Working Group investigating the possibility of earthquakes being triggered by impounding water in reservoirs. Dr. Okamoto also founded the Committee for Dam Safety' International Commission on Large Dams. Dr. Okamoto had been the recipient of many honors, including the Prize for Distinguished Achievement presented by the Japan Society of Civil Engineers, and the Fujiwara Medal. In 1979, he was decorated with the Purple-Ribbon by the Emperor of Japan for his outstanding achievements in earthquake engineering. He was designated a Person of Cultural Merit in l989. An excellent lecturer, Dr. Okamoto had left his mark on the many students he has taught at the University of Tokyo. Many of them are now the leaders in earthquake engineering in Japan. |
| Choshiro TAMURA, PhD. |
 Dr. Choshiro TAMURA, Emeritus Professor at the University of Tokyo, had been on his carrier path at the Institute of Industrial Science, University of Tokyo since 1965 till 1991. His early professional life was spent in search for a rational approach to the evaluation of the dynamic earthquake resistance of a variety of soil-structure systems such as tunnels, earthfill and rockfill dams etc. Through long-term observations of behaviors of underground fascilities, he showed many clear evidences that underground fascilities follow closely the motions of their surrounding soils. These findings clearly showed that the most important key to a rational design of underground fascilities is to evaluate responses of surface soil deposits with irregular shapes, and his first outstanding achievement is found in his paper entitled gBehaviors of submerged tunnels during earthquakes" that appeared in the International Journal of Earthquake Engineering and Structural Dynamics, Vol. 1 (1973). The method described in this paper was a truly great breakthrough in simplifying the analysis of tunnels, and was put, with the later rapid development of computers, to great practical use. Dr. Tamura also proposed an empirical relation between seismic motions on rocks and epicentral distances. He had been aware of the fact that a surface soil deposit can amplify the ground motion remarkablly, and attenuations of seismic motions can be rationally described only by elliminating the effect due to the presence of soft soil deposits. At that time in Japan, the question of whether dams could sustain considerable seismic loading was a matter of great concern, and his empirical equation has allowed huge dams to be effectively designed and constructed in Japan. Dr. Tamura had glearn from failuresh as his motto, and has actually made frequent reconnaissance trips, sometimes as leaders of teams officially dispatched by the Japan Society of Civil Engineers, to see with his own eyes, failures caused by devastating events. On these occasions, he has repeatedly shown his valuable ability to quickly identify the most important components of a complex phenomenon. Dr Tamura had a proud record of service in various organizations in Japan. In his capacity as chairman of the JSCE committees of Earthquake Engineering, Submerged tunnels etc. Immediately after the killer Kobe Earthquake of 1995, JSCE organized a special assmbly for reviewing problems for seismic designs. Dr. Tamura, as the chairman of this review assembly, has devoted much of his energy to make official JSCE recommendations for seismic designs of civil-infrastructures (1st version on May 23rd, 1995, 2nd version on Jan. 10th, 1996), and important design regulations for railways, tunnels etc have been revised along with these reDr. Choshiro TAMURA, Emeritus Professor at the University of Tokyo, had been on his carrier path at the Institute of Industrial Science, University of Tokyo since 1965 till 1991. His early professional life was spent in search for a rational approach to the evaluation of the dynamic earthquake resistance of a variety of soil-structure systems such as tunnels, earthfill and rockfill dams etc. Through long-term observations of behaviors of underground fascilities, he showed many clear evidences that underground fascilities follow closely the motions of their surrounding soils. These findings clearly showed that the most important key to a rational design of underground fascilities is to evaluate responses of surface soil deposits with irregular shapes, and his first outstanding achievement is found in his paper entitled gBehaviors of submerged tunnels during earthquakes" that appeared in the International Journal of Earthquake Engineering and Structural Dynamics, Vol. 1 (1973). The method described in this paper was a truly great breakthrough in simplifying the analysis of tunnels, and was put, with the later rapid development of computers, to great practical use. Dr. Tamura also proposed an empirical relation between seismic motions on rocks and epicentral distances. He had been aware of the fact that a surface soil deposit can amplify the ground motion remarkablly, and attenuations of seismic motions can be rationally described only by elliminating the effect due to the presence of soft soil deposits. At that time in Japan, the question of whether dams could sustain considerable seismic loading was a matter of great concern, and his empirical equation has allowed huge dams to be effectively designed and constructed in Japan. Dr. Tamura had glearn from failuresh as his motto, and has actually made frequent reconnaissance trips, sometimes as leaders of teams officially dispatched by the Japan Society of Civil Engineers, to see with his own eyes, failures caused by devastating events. On these occasions, he has repeatedly shown his valuable ability to quickly identify the most important components of a complex phenomenon. Dr Tamura had a proud record of service in various organizations in Japan. In his capacity as chairman of the JSCE committees of Earthquake Engineering, Submerged tunnels etc. Immediately after the killer Kobe Earthquake of 1995, JSCE organized a special assmbly for reviewing problems for seismic designs. Dr. Tamura, as the chairman of this review assembly, has devoted much of his energy to make official JSCE recommendations for seismic designs of civil-infrastructures (1st version on May 23rd, 1995, 2nd version on Jan. 10th, 1996), and important design regulations for railways, tunnels etc have been revised along with these recommendations. He served as the President of the Japan Society of Dam Engineering in 1996. Dr. Tamura had been the recipient of many honors, including the Prize for the best journal paper of the year (with K. Konagai 1993), the Japan Society of Civil Engineers, and the JSCE Lifetime Achievement Award, 2003. An excellent lecturer, Dr. Tamura had left his mark on the many students he has taught at the University of Tokyo. Many of them are now the leaders in earthquake engineering in Japan. |
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