The George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) is a project funded under the NSF Major Research Equipment and Facilities Construction appropriation. This cooperative agreement, under NEES, establishes two permanently instrumented field sites for monitoring soil-foundation-structure interaction (SFSI), ground motion, ground deformation, and pore-water pressure responses. The field sites will be used to monitor responses generated by local and regional earthquakes and for active experiments with excitation by shakers such as those being constructed by other NEES projects at the University of California, Los Angeles (NSF NEES award CMS-0086596 and the University of Texas, Austin (NSF NEES award CMS-0086605). These two field sites are being developed by a team of investigators led by Brigham Young University (BYU), in partnership with the University of California at Santa Barbara (UCSB) and the University of Southern California (USC). The sites will be connected to the NEES network system through a high performance network. This equipment will be operational by September 30, 2004, and will be managed as a national shared-use NEES equipment site, with teleobservation and teleoperation capabilities, to provide new earthquake engineering research testing capabilities for geotechnical and SFSI testing through 2014. Shared-use access and training will be coordinated through the NEES Consortium. This award is an outcome of the peer review of proposals submitted to program solicitation NSF 01-164, "NEES Earthquake Engineering Research Equipment, Phase 2." The NEES equipment will be located as permanently instrumented field arrays at two sites in Southern California: the Garner Valley Downhole Array (GVDA) in Riverside County, east of Hemet, California, and the Salton Sea Wildlife Refuge Liquefaction Array (WLA) in Imperial County near Calipatria, California. Both sites are located adjacent to major faults and have previous histories of recording ground motions and pore-water pressures. The two sites are underlain by soft, liquefiable ground. The instrumentation at GVDA will be upgraded and enhanced for real-time data transmission. A reconfigurable, one-story structure will be constructed at that site and instrumented with sensors installed in the structure, foundation, and underlying soil. A small shaker will be permanently mounted on the roof of the building; larger shakers may be brought to the site and placed on the building or on a nearby pad to artificially excite the structure and underlying ground. Instrumentation at WLA will be upgraded and greatly expanded to allow monitoring of three-dimensional ground motion and pore-water pressure responses. Communications equipment capable of concurrent data transmission and teleobservation will allow rapid delivery of data to the NEES network and remote participation in experiments conducted at the sites. There is need to further study SFSI in real structures under seismic input, but there are always complexities in real structures that can mask understanding of SFSI phenomena. Study of ground failure is also complicated in urban or geologically complex settings. Simple, well-characterized test sites like these two are needed to increase understanding of the physics behind SFSI, ground response, and ground failure during earthquakes. This pair of NEES field sites will also provide an excellent test bed for new in-situ site characterization techniques and new sensor technologies. The field sites will have an impact on undergraduate and graduate teaching programs in earthquake engineering, geotechnical engineering, and engineering seismology by allowing students to participate in the active experiments through teleparticipation as well as on-site workshops. Data from both sites will be contributed to the NEES Data Repository and the Advanced National Seismic System (ANSS). The collected information will aid development and verification of simulation models for ground response, pore-water pressure generation, and dynamic SFSI. Improved simulation of these fundamental earthquake engineering phenomena will lead to better, safer and more economical engineering design. BYU, UCSB, and USC will integrate experimentation at these sites into their research program and curricula, provide training opportunities for outside researchers through on-site courses and web-based materials, and host visiting scholars.
