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)计划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。这项合作协议根据NEES计划，在奥斯汀的德克萨斯大学(UT)建立了一个NEES地震工程现场实验场。UT将为岩土和结构地震工程实验设计、购买、建造、安装、调试和运营新的移动、大型现场设备。该设备将在2004年或更早时候投入使用，并将作为具有远程呈现能力的国家共享NEES设备站点进行管理，以提供到2014年的新的地震工程研究测试能力。NEES设备点将通过高性能网络连接到NEES协作室。共享使用准入和培训将通过NEES联盟进行协调。该奖项是对提交给NSF 00-6，NEES：地震工程研究设备项目征集的建议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于新结构的设计和现有结构的修复是至关重要的。目前，对土的液化和沉降、侧向扩展和场地扩大的预测都是基于小应变的实验室和现场测试，这不能复制在大地震期间发生的非线性应变水平。将开发移动的大型现场设备，以在地面产生与地震期间相媲美的动态运动。该设备包括一个大型三维移动振动筛；两个立方体独立三维振动筛；一辆装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。大型三维移动振动器将能够在11到200赫兹的频率范围内在垂直方向上产生高达267 kN(60,000磅)的力，在5到200赫兹的频率范围内在水平方向上产生高达133 kN(30,000磅)的力。两个独立的立方振动器还将能够在水平或垂直方向上产生力。一个立方振动器将在2.6至800赫兹的频率上产生18kN(4000磅)的力，而另一个振动器将在0.7至125赫兹的频率上产生57kN(12,800磅)的力。它们将在建筑物内和可液化矿藏的顶部使用。具体的仪器将包括低频和高频加速计、三轴1赫兹地震检波器、孔压传感器、高速数据采集、波形记录器信号处理能力和无线技术。这些设备将以德克萨斯大学为基地，但将安装在卡车上，并可作为NEES共享设备在美国各地重新部署。该设备将用于：1)现场表征岩土材料的非线性地震性能和抗液化能力；2)有效和高效地对岩土环境的重要区域进行三维成像，包括1至2公里范围内300至500米的深度；以及3)调查和记录实际岩土环境中大型或全尺寸基础或结构的动态响应。使用该设备的现场实验将显著增强我们对与岩土材料相关的地震影响的基本知识，从而减少未来地震造成的生命损失和经济损失。UT将把这一现场设备整合到其研究计划以及本科生和研究生课程中，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.