INDUSTRY

Researchers from NCSA, University of Illinois collaborate with a major Japanese construction firm to conduct NEESgrid's first trans-Pacific earthquake engineering simulation — Earthquake engineers were able to conduct a collaborative experiment that spanned the Pacific Ocean last month thanks to the NEESgrid cyberinfrastructure, which links earthquake engineering researchers across the United States with leading-edge computing resources and experimental facilities. On March 26, earthquake engineers from the University of Illinois at Urbana-Champaign and NEESgrid grid technology developers from the National Center for Supercomputing Applications (NCSA) and around the country partnered with the Kajima Corporation, a leading Japanese civil engineering firm, to conduct the first trans-Pacific simulation using NEESgrid. Sponsored by the National Science Foundation (NSF), NEESgrid is a virtual "collaboratory" that lets engineering research teams collaboratively plan, perform and publish research even while separated geographically by thousands of miles. "NEESgrid is the nation's first engineering cyberinfrastructure initiative," says B. F. Spencer, Jr., who is the Nathan M. and Anne M. Newmark Endowed Chair of Civil Engineering at UIUC and principal investigator for NEESgrid. In addition to UIUC and NCSA, other research institutions leading the development of NEESgrid include Argonne National Laboratory, the University of Southern California and the USC Information Science Institute, Pacific Northwest National Laboratory, the University of California at Berkeley, Mississippi State University, Stanford University, and Washington University. The trans-Pacific experiment simulated a two-span frame structure that was divided by a central column. The central column was represented by a computer model, while the outer columns were physically installed at UIUC and Kajima. The structure was exposed to a 15-second seismic excitation, which was subdivided into time steps of 0.01 seconds. At each time step, the deformation of the outside column was calculated on a computational node using an analytical model of the central column-beam frame. The deformation was then sent to the experimental sites at Kajima and UIUC and applied to the respective test structures. The reaction forces associated with these test structures was then measured and returned to the computational node, where they were used to calculate the response of the next time step. The process was continually repeated for the duration of the seismic excitation. Both physically generated and simulated data were combined via the NEESgrid, which also allowed participants to communicate with each other and observe the experiment in progress. One measure of the experiment's success is that the simulation generated calculations that very closely approximated results from the physical experiment. The trans-Pacific simulation built on the successful Multi-Site Online Simulation Test (MOST) experiment, which was carried out in July 2003 on a larger scale at sites across the United States. Dubbed "Mini-MOST," the smaller setup can be used to test and verify installed NEESgrid nodes safely and inexpensively before larger experiments are conducted. Earthquake engineering research has traditionally relied on expensive physical testing restricted to institutions that possess earthquake simulation equipment such as shaking tables. However, when the NEESgrid is fully operational this fall, it will make possible the integration of physical experimentation and model-based simulation, computational analysis, and improved testing and validation of more complex and comprehensive analytical and numerical models. Additionally, NEESgrid's data repository structure will make experimental data and metadata from these tests more easily accessible to the earthquake engineering community. The prospect of NEESgrid nodes at Japanese experimental facilities promises considerable opportunities for future collaboration between researchers in Japan and the United States, with the potential for substantial advancements in earthquake engineering research. NEES will enable researchers to carry out complicated earthquake engineering simulations more efficiently both by using Kajima's experimental facilities and computer resources effectively and by cooperating with the network of university research resources in the United States. Researchers from both NEES and Kajima anticipate that the simulation of larger, more complicated structures will be carried out by Japan-U.S. collaborations in the near future. "Because of the long history—nearly 40 years—of collaboration between the U. S. and Japan in earthquake engineering, NEES should also facilitate more effective and productive bilateral U.S.-Japan collaboration," says Spencer. NEESgrid is supported by The George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES), a national earthquake engineering project funded by NSF. NCSA (National Center for Supercomputing Applications) is a national high-performance computing center that develops and deploys cutting-edge computing, networking and information technologies. Located at the University of Illinois at Urbana-Champaign, NCSA is funded by the National Science Foundation. Additional support comes from the state of Illinois, the University of Illinois, private sector partners and other federal agencies. For more information, see http://www.ncsa.uiuc.edu/.