NEESR-SG: Seismic Performance Assessment in Dense Urban Environments

这个奖项是NSF 08-519计划征集的结果？乔治E.小布朗地震工程模拟研究网络（NEES）该奖项由加州大学伯克利分校（牵头机构）、布法罗-纽约州立大学（子奖项）、加州大学戴维斯分校（子奖项）、加州大学圣地亚哥分校（子奖项）、加州州立理工大学圣路易斯奥比斯波分校（子奖项）和地震工程研究大学联盟（子奖项）共同颁发。 本项目将利用位于加州大学戴维斯分校的NEES设备场地（加州大学戴维斯分校岩土工程设备）。在我们的城市中，建筑物是在集群（城市街区）中建造的。 理想情况下，它们应该被设计为抵抗地震力的建筑群，因为一个建筑物的反应可以影响相邻建筑物的反应。 然而，密集分布的建筑物之间的相互作用在当前的设计实践中没有被捕获，因为建筑物通常被设计为孤立的结构。 土-结构相互作用（SSI）对密集低层和中高层建筑的影响知之甚少。 例如，不清楚不同大小的地下室如何影响地面如何震动这些建筑物。 最近的地震破坏了城市中的建筑群，但由于缺乏地面运动和建筑性能的记录，很难从这些观测中学习。 然而，一个全面的计划，现实规模的离心机实验，输入运动，地面条件，地面响应，结构响应可以仔细跟踪，然后通过这些模型试验的反分析，可以用来提高专业？的理解，SSI的影响，建筑物在密集的城市环境。 NEES UC Davis离心机的独特功能将用于提高我们对建筑群SSI效应的理解，以便进行可靠的评估。 在离心机中，装有土壤和模型建筑物的盒子以50 g的旋转加速度旋转，使得2英尺厚的土壤具有与100英尺厚的土壤相同的应力。 建筑模型的比例相似，因此在这些实验中测量了真实的响应。该测试程序将开发一个数据库，有据可查的模型？病历在密集的城市环境中，在经历中度和严重地面震动的场地，无论是否发生地面破坏， 然后，研究人员可以利用这些实验结果来提高我们对这些现象的理解和分析它们的能力。 物理实验和数值模拟将使我们能够为设计师和政策制定者提供指导，帮助他们了解建筑群在地震中的表现。该项目将推进基础科学和工程知识，为岩土工程和结构工程学科带来实质性的知识效益。 这两个学科将有助于并受益于综合性能抗震设计和可靠的损失估算方法的开发和部署。 该项目还将培养博士。学生，从教学大学引进本科生，吸引代表性不足的学生，影响建筑规范的制定和基于性能的抗震设计，并通过强调网络访问媒体来推广到广泛的最终用户。 我们还将翻译的挑战，解决这个现实的问题，本科生（和其他人）通过？城市街区的震动？振动台比赛，让学生考虑相邻结构和土壤对抗震性能的影响。 该项目的数据将通过NEES数据储存库（http：//www.example.com）提供。www.nees.org

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 the University of California, Berkeley (lead institution), University of Buffalo-SUNY (subaward), University of California, Davis (subaward), University of California, San Diego (subaward), California Polytechnic State University, San Luis Obispo (subaward), and the Consortium of Universities for Research in Earthquake Engineering (subaward). This project will utilize the NEES equipment site at the University of California, Davis (the UC Davis Geotechnical Centrifuge Facility). In our cities, buildings are constructed in clusters (the city block). Ideally, they should be designed to resist earthquake forces as clusters of buildings, because the response of one building can affect the response of neighboring buildings. However, the interactions between densely spaced buildings are not captured in current design practice, because buildings are typically designed as isolated structures. Soil-structure interaction (SSI) effects on closely spaced low- and medium-rise buildings are poorly understood. For example, it is not clear how basements of different sizes affect how the ground shakes these buildings. Recent earthquakes have damaged groups of buildings in cities, but it is difficult to learn from these observations due to the lack of documentation of the ground motion and building performance. However, a comprehensive program of realistic scaled centrifuge experiments, where the input motion, ground conditions, ground response, and structural response can be carefully tracked, followed by back-analyses of these model tests, can be employed to enhance the profession?s understanding of SSI effects of buildings in a dense urban environment. The unique capabilities of the NEES UC Davis centrifuge will be used to advance our understanding of SSI effects for clusters of buildings so that reliable assessments can be made. In a centrifuge, a box containing soil and model buildings is spun at a rotational acceleration of 50 g so that a 2 foot thickness of soil has the same stresses as a 100 foot thickness of soil. Building models are scaled similarly so realistic responses are measured in these experiments. The testing program will develop a database of well-documented model ?case histories? of building performance within a dense urban environment at sites undergoing moderate and severe ground shaking with and without ground failure. Researchers can then use these experimental results to advance our understanding of these phenomena and our ability to analyze them. Physical experiments followed by numerical simulations will allow us to develop guidance for designers and policy makers on how clusters of buildings perform during earthquakes. This project will advance fundamental science and knowledge in engineering with substantial intellectual benefits to both geotechnical and structural engineering disciplines. Both disciplines will contribute to and benefit from the development and deployment of an integrated performance-based seismic design and a robust loss-estimation methodology. The project will also train Ph.D. students, bring in undergraduate students from a teaching university, engage under-represented students, impact building code development and performance-based seismic design, and outreach to a broad spectrum of end-users by emphasizing web-accessed media. We will also translate the challenge of solving this realistic problem to undergraduates (and others) via a ?Shaking of a City Block? shaking table competition to have students consider the effects of adjacent structures and soil on seismic performance. Data from this project will be made available through the NEES data repository (http://www.nees.org).