NEESR-II: Advanced Site Monitoring and Effective Characterization of Site Nonlinear Dynamic Properties and Model Calibration

该奖项是NSF 08-519计划征集小乔治·E·布朗的成果。地震工程模拟(NEES)研究网络(NEESR)竞赛，包括伦斯勒理工学院(牵头机构)和曼哈顿学院(次级奖项)。该项目将利用加州大学圣巴巴拉分校、德克萨斯大学奥斯汀分校和伦斯勒理工学院的NEES设备场地。在地震激励下，场地液化往往与巨大的永久位移和横向扩散有关，这会对所有类型的土木工程系统造成代价高昂的破坏。然而，直到最近，永久位移的实时现场测量一直是研究人员和实践者的难题，并阻碍了预测场地横向扩展和破坏的可靠工具的开发。该项目提出了一项研究计划，旨在发展一种能力，以监测现场场地的循环和永久位移，并使用相关测量来表征从地表到约30米深的土层的现场低应变和大应变动态特性。将在NEES@UCSB野生动物液化场地永久安装一些无线形状加速度阵(WSSA)，以监测低应变响应以及地震引起的液化、永久变形和横向扩展。预计在不久的将来，地震将在该地点引起大的永久变形。然后，安装的阵列将首次提供场地横向扩展剖面的时间历史的测量。具体地说，该项目包括以下任务：(1)利用离心机模型试验和计算分析开发和验证最佳阵列配置，(2)在NEES@UCSB野生动物液化场地的最佳配置内安装一些无线形状加速阵列，(3)使用NEES@Texas T-Rex可控震源对场地进行激励，以及(4)开发创新的数据简化和识别工具，以估计野生动物场地以及未来可能被测量的其他野外场地的三维(小应变和大应变)动态特性和响应机制。该项目将对我们在现场测试土壤系统、评估其(低应变和大应变)力学特性以及校准这些系统的计算模型的能力产生广泛的影响，同时避免土壤样本干扰的问题和小规模或样本测试的限制。计划中的研究结果将有助于开发更强大的土壤系统建模程序和预测工具，以减少与地震有关的损失。伦斯勒和曼哈顿学院的拟议课程开发将加速和加强工程教育中正在出现的新范式，在这种范式中，实践经验是有效传播知识的催化剂之一。该项目的数据将通过NEES数据库(http://www.nees.org).)提供

This award is an outcome of the NSF 08-519 program solicitation George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)competition and includes Rensselaer Polytechnic Institute (lead institution) and Manhattan College (subaward). This project will utilize the NEES equipment sites at the University of California at Santa Barbara, the University of Texas at Austin and Rensselaer Polytechnic Institute. Site liquefaction during earthquake excitations is often associated with significant permanent displacement and lateral spreading that lead to costly damage to civil systems of all types. However, realtime field measurements of permanent displacements have eluded researcher and practitioners until recently, and hindered the development of reliable tools to predict site lateral spreading and failure. This project proposes a research program to develop a capability to monitor the cyclic and permanent displacement of field sites and use the associated measurements to characterize the in situ low and large strain dynamic properties for soil strata ranging from the ground surface to a depth of about 30 meters. A number of wireless shape-acceleration arrays (WSSA) will be installed permanently at the NEES@UCSB Wildlife liquefaction site to monitor low strain response as well as earthquake induced liquefaction, permanent deformation and lateral spreading. It is anticipated that an earthquake in the near future will induce large permanent deformation at this site. The installed arrays would then provide for the first time measurement of the time history of a site lateral spreading profile. Specifically, this project comprises the following tasks: (1) development and validation of optimal array configurations using centrifuge model tests and computational analyses, (2) installation of a number of wireless shape-acceleration arrays within an optimal configuration at the NEES@UCSB Wildlife liquefaction site, (3) excitation of the site using the NEES@Texas T-Rex vibrator, and (4) development of innovative data reduction and identification tools to estimate the 3-dimensional (small and large strain) dynamic properties and response mechanisms of the Wildlife site as well as other field sites that may be instrumented in the future.This project will have a broad impact on our capabilities to test in situ soil systems, evaluate their (low and large strain) mechanical properties and calibrate computational models of these systems, all while avoiding the issues of soil sample disturbance and limitation of small scale or sample testing. The outcome of the planned research will contribute to the development of more robust modeling procedures and predictive tools of soil systems to reduce losses associated with earthquakes. The proposed curriculum development at Rensselaer and Manhattan College will accelerate and enhance the emerging new paradigm in engineering education where hands-on experience is one of the catalysts for effective transmission of knowledge. Data from this project will be made available through the NEES data repository (http://www.nees.org).