The National Science Foundation's (NSF) Tokyo Office periodically receives and disseminates reports on research developments in Japan that are related to the Foundation's mission. NSF-sponsored researchers currently working in Japan prepare many of these reports. These reports present information for use by NSF program managers and policy makers; they are not statements of NSF policy. .
Special Scientific Report #98-18 (October 12, 1998)
Ms. A'gota Fejes, a Ph.D. student in the Department of Civil Engineering, Polytechnic University, Brooklyn, New York, prepared the following report. Ms. Fejes was a participant in the 1998 Monbusho Summer Program sponsored by NSF and the Ministry of Education, Science, Sports and Culture (Monbusho). Professor Kazuhiko Kawashima in the Department of Civil Engineering at the Tokyo Institute of Technology (TIT), Tokyo, Japan hosted Ms. Fejes. Ms. Fejes can be reached via email at: afejes01@utopia.poly.edu
Purpose:
Seismic strengthening has been conducted on reinforced concrete bridge piers that were designed and constructed in accordance with the seismic codes before 1980. Concrete bridge piers have failed because not enough consideration of the ductility requirements was taken into account prior to 1980. The results were failures. Examples of failure include bridges affected by the North Ridge earthquake on January 17, 1994 and the Hyogo-ken Nanbu earthquake on January 17, 1995. It is necessary to find a better mathematical model that is easy to use and provides viable solutions to problems in reinforced concrete pier design.
View of Past:
Previous studies on confinement effects of lateral reinforcement in columns have already been conducted by Kent and Park (1971), Sheikh and Uzumeri (1982), Mander et al. (1988), Saatcioglu and Razvi (1992), Muguruma (1980), Fuji et al (1988), Hoshikuma et al. (1997).
Objective:
The Mander et al. and Hoshikuma et al. models were used for the stress - strain calculations with J. Sakai's (TIT) circle columns and M. Hosotani's (Taisei Corp.) circle and square columns data.
Conclusion:
Using J. Sakai's experimental data the Mander equation gives very close result to the experimental data. However, Hoshikuma's equations give much higher results than the experiment. A similar conclusion with Hosotani's circle test resulted but there is some inconsistency with Hosotani's square results. In those cases, the Mander equation gives very similar results in small steel ratio (less than 1.33%) and the Hoshikuma equation provides similar or slightly higher results than the experimental in steel ratio higher than 1.33%.
Perspective of research after this program:
The Monbusho program provided me with a very valuable perspective (and a wonderful opportunity for me) for beginning my research and helped me to establish a base for future research. I was able to learn and analyze much more than if I had remained in New York. This is largely due to the guidance of my host, Professor Kawashima, and his students. Our discussions led me to the results I was able to attain. I must thank for the Monbusho Program for this truly unique academic experience. I plan to stay in contact with my host professor and his students in the future.
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