Large-Scale Mobile Shakers and Associated Instrumentation for Dynamic Field Studies of Geotechnical and Structural Systems

地震工程模拟网络（NEES）项目是美国国家科学基金会重大研究设备计划资助的一个项目。根据NEES项目的合作协议，在德克萨斯大学奥斯汀分校建立了一个NEES地震工程现场实验基地。UT将设计、购买、建造、安装、调试和操作新的移动大型现场设备，用于岩土和结构地震工程实验。该设备将于2004年或更早投入使用，并将作为国家共享使用的NEES设备站点进行管理，具有远程呈现能力，到2014年提供新的地震工程研究测试能力。该NEES设备站点将通过高性能网络连接到NEES合作实验室。共享使用的获取和培训将通过NEES联盟进行协调。该奖项是对提交给项目招标NSF 00-6， NEES：地震工程研究设备的提案进行同行评审的结果。了解近地表地质材料对地震荷载的响应对新结构的设计和现有结构的修复至关重要。目前，对土壤液化和沉降、横向扩展和场地放大的预测是基于小应变实验室和现场测试，不能复制大地震期间发生的非线性应变水平。将开发可移动的大型现场设备，以在地面上产生与地震时产生的动态运动相媲美的动态运动。该设备包括一个大型三维移动式振动筛；两个立方体，独立的三维激振器；带有现场设备和多通道数据采集和处理系统的仪表车；以及用于远程参与的通信设备。这款大型3d移动式振动筛在垂直方向上可在11 ~ 200 Hz频率范围内产生高达267 kN （60000 lb）的力，在水平方向上可在5 ~ 200 Hz频率范围内产生高达133 kN （30000 lb）的力。两个独立的立方体激振器也将能够在水平或垂直方向上产生力。一个立方体激振器在2.6到800赫兹的频率范围内产生18千牛（4000磅）的力，另一个激振器在0.7到125赫兹的频率范围内产生57千牛（12800磅）的力。它们将用于建筑物内部和可液化沉积物的顶部。具体的仪器将包括低频和高频加速度计、三轴1赫兹检波器、孔隙压力传感器、高速数据采集、波形记录仪信号处理能力和无线技术。该设备将以德克萨斯大学为基地，但将作为NEES共享使用设备安装在卡车上，便于在美国各地搬迁。该设备将用于：1)对岩土材料的非线性抗震性能和抗液化性能进行现场表征；2)有效和高效的岩土环境重要区域的三维成像，包括距离为1至2公里，深度为300至500米；3)调查和记录大型或全尺寸地基或结构在实际岩土工程环境中的动态响应。使用该设备的现场实验将大大提高我们对与地质材料相关的地震效应的基本知识，从而减少未来地震造成的生命损失和经济损失。德克萨斯大学将把这种现场设备整合到其研究项目、本科和研究生课程中，并为外部研究人员提供培训机会。

CMS-0086605StokoeThe 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 earthquake engineering field experimentation site at the University of Texas (UT) at Austin. UT will design, purchase, construct, install, commission, and operate new mobile, large-scale field equipment for geotechnical and structural earthquake engineering experimentation. This equipment will be operational by 2004 or earlier and will be managed as a national shared-use NEES equipment site, with telepresence capabilities, to provide new earthquake engineering research testing capabilities through 2014. This NEES equipment site will be connected to the NEES collaboratory through a high performance network. 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. Understanding of the response of near-surface geologic materials to earthquake loading is essential to the design of new structures and the remediation of existing structures. Currently, prediction of soil liquefaction and subsidence, lateral spreading, and site amplification are based on small-strain laboratory and field testing, which does not duplicate the nonlinear strain levels that occur during major earthquakes. Mobile, large-scale field equipment will be developed to produce dynamic motion in the ground comparable to that produced during earthquakes. This equipment includes a large three-dimensional mobile shaker; two cubical, stand-alone three-dimensional shakers; an instrumentation van with field equipment and multi-channel data acquisition and processing systems; and communications equipment for teleparticipation. The large, 3-D mobile shaker will have the ability to generate up to 267 kN (60,000 lb) of force in the vertical direction over a frequency range of 11 to 200 Hz and up to 133 kN (30,000 lb) of force in the horizontal direction over a frequency range of 5 to 200 Hz. The two stand-alone cubical shakers will also be able to generate force in either the horizontal or vertical direction. One cubical shaker will generate forces of 18 kN (4000 lb) over frequencies from 2.6 to 800 Hz, and the other shaker will generate forces of 57 kN (12,800 lb) over frequencies from 0.7 to 125 Hz. They will be used inside buildings and on top of liquefiable deposits. Specific instrumentation will include low and high frequency accelerometers, triaxial 1-Hz geophones, pore pressure transducers, high-speed data acquisition, waveform recorder signal processing capabilities, and wireless technology. The equipment will be based at UT, but will be truck mounted and portable for relocation throughout the U.S. as NEES shared use equipment. The equipment will be used for: 1) characterizing the nonlinear earthquake performance and liquefaction resistance of geomaterials in situ; 2) effective and efficient 3-D imaging of significant zones of the geotechnical environment, including depths of 300 to 500 m over distances of 1 to 2 km; and 3) investigating and documenting the dynamic response of large-scale or full-scale foundations or structures in actual geotechnical settings. Field experiments using this equipment will significantly enhance our fundamental knowledge of earthquake effects associated with geomaterials, thereby reducing loss-of-life and economic losses from future earthquakes. UT will integrate this field equipment into its research program and undergraduate and graduate curricula and provide training opportunities for outside researchers.