The George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Program is a project funded under the NSF Major Research Equipment Program. This cooperative agreement, under the NEES Program, establishes a NEES reconfigurable reaction wall-based earthquake simulator facility at the University of California, Berkeley (UCB), California. UCB will design, construct, install, commission, and operate a modular and highly flexible dynamic testing facility that will enable experimental and analytical model-based simulation of interactions among substructures that form a single structure. The knowledge gained from such simulations will help develop a new generation of performance-based design guidelines and implement them in practice to improve the safety and reliability of civil infrastructure. This equipment will be operational by September 30, 2004, or earlier 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 large structural systems through 2014. This NEES equipment site will be connected to the NEES collaboratory through the University's Abilene connection, with 1-2 Gb/sec Ethernet capabilities. 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 00-6, "NEES: Earthquake Engineering Research Equipment." The equipment will be installed in Building 484 at the Richmond Field Station of UCB and will make use of the existing strong floor, existing four-million-pound axial compression-tension testing machine, and an array of existing static and dynamic actuators. The following equipment is provided under this award: (1) reconfigurable reaction wall, with post-tensioning bars and couplers, (2) seven dynamic and static actuator assemblies: four dynamic, two rated at 50 kips (222 kN) with 40-in (1016 mm) stroke minimum and two rated at 150 kips (667 kN) with 40-in (1016 mm) stroke minimum, and three static, one rated at 446/600 kips (1984/2669 kN) with 40-in (1016 mm) stroke and two rated at 216/328 kips (961/1459 kN) with 72-in (1829 mm) stroke, (3) one hydraulic distribution system, (4) one high-performance accumulation system, (5) one digital control system with real-time hybrid control packages and integrated data acquisition channels, comprising hardware for 8 control channels and 16 additional data acquisition channels and software development kits, (6) advanced data acquisition system with a modular 128-channel data acquisition system with A/D converter, (7) digital video teleobservation system including a system of digital cameras, digital video recorders and a digital video Internet server, (8) instrumentation that includes potentiometer-based displacement sensors, MEMS-based accelerometers, load cells, tilt-meters, cabling, and connectors, and (9) network interface hardware. The reaction wall consists of concrete modules, hollow-core blocks designed to be mated at the top and bottom and postensioned into a monolithic unit. The same postensioning will be used to connect the reaction wall to the strong floor. At least 14 blocks will make it possible to configure a single 42-ft (12.8 m) reaction wall or two 21-ft (6.4 m) tall walls. Numerous combinations of walls and arrangements will be possible with this modular strong wall concept. A network interface will enable cooperative hybrid testing between an existing shaking table and the reaction wall. Furthermore, a network interface to the University of California Millennium cluster will provide access to a massively parallel computation facility necessary to implement the multiply substructured pseudo-dynamic testing method. The experimental facility is designed to support the development of a new generation of hybrid testing methods that smoothly integrate physical and numerical simulations. Portions of the structure, expected to behave in a predictable manner, are modeled numerically, while one or more complex subassemblies and the boundaries on which they interact are modeled using scaled physical models. Using numerical integration algorithms, the physical and numerical substructures can be analyzed as a single structure. The substructures, physical or numerical, involved in such hybrid testing can be at different geographic locations connected by the NEES network. UCB will integrate this reconfigurable reaction wall-based earthquake simulator into its research program and undergraduate and graduate curricula (including making the material widely available in online web-based course modules), and provide training opportunities for outside researchers through on-site courses and web-based materials.
