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. .
Ms. Joyce Feng, a graduate student in the College of Engineering at University of California, Berkeley, prepared the following report. Ms. Feng is a participant in the 1999 Summer Institute sponsored in the United States by NSF/NIH/USDA and the Science and Technology Agency and Japan Science and Technology Corporation in Japan. Dr. Isao Nishiyama of Building Research Institute in Tsukuba, hosted Ms. Feng. Ms. Feng can be reached via email at: fjoyce@uclink4.berkeley.edu
Being in the Building Research Institute this summer broadened
my perspective immensely as a structural design engineer. Not
only did I learned about Japanese design standards, I learned
about the necessity of flexibility in design and the demand for
practicality from the construction standpoint.
The focus of my summer research was on structural steel welding using robotics. For this purpose, I have read numerous papers on the welding process, in addition to visiting steel fabricators and construction sites. At the Building Research Institute, there is a robot used in testing the hypothesis and ideas for welding with different parameters. Using a robot for research gives the advantage of consistency. Difference in parameters, such as heat input, plate positioning, torch inclination, and velocity of welding can affect the behavior of the weld tremendously. The purpose of the research is to find the combination that would give the best welding performance so as to prevent brittle behavior of connections as seen in steel structures after the Hyogo-ken Nanbu (or Kobe) and Northridge Earthquakes.
A secondary part of my summer at BRI included studying the recently proposed Earthquake-Resistant Limit-State Design for Buildings as presented by Professor H. Akiyama. The idea of enhancing the energy absorption capacity of structures, through, for example, base isolation and damping mechanisms, originate from the energy concept of earthquake input motion and energy absorption capacity of structures. As part of my studies, I examined the behavior of different structural design types in terms of the energy concept.
I worked closely with some of the researchers at BRI and was able to become familiar with their analytical and experimental research. Of particular interest was the study on the influence of relative member strengths of beam-column-joint panel on the seismic behavior of steel buildings. In addition, having one of the best testing facilities in the world, BRI provided a great opportunity to see experimental researches in progress. For instance, I was able to witness a soft story experiment.
My host lab advisor, Dr. Nishiyama, was able to arrange many professional visits outside of BRI. I was able to visit and tour the largest shaking table in the world in Tadotsu and saw an experiment with LNG (liquid natural gases) storage tanks performed on the shaking table. I went to Ando Construction Corporation and was shown a number of concrete and steel construction sites and examined connections and welding processes and inspection techniques, such as the ultrasonic testing.
I am extremely grateful to NSF and JISTEC and everyone at my host laboratory for making all this possible.