SGER: Large-Scale Validation of Seismic Performance of Bridge Columns

探索性研究小额资助（SGER）项目的目标是：(1)提供其他研究人员、从业人员和资助机构可以参与的核心；(2)积极配合策划E-Defense桥柱试验方案；(3)编译和分发（根据NEES Consortium， Inc.和E-Defense政策）来自整个测试系列的数据，包括NEES数据存储库中的存档；(4)进行一系列与当前美国设计实践详细一致的全尺寸桥柱试验；(5)根据E-Defense测试项目的其他数据，以及此前在美国进行的小规模测试，解读这些数据；(6)采用先进的基于物理的模型以及设计实践中使用的较简单的现象学模型进行数值模拟；(7)根据这些测试和分析评估当前的设计和分析实践；(8)广泛传播成果。主要的交通结构，如桥梁，在最近的地震中遭受了巨大的破坏，如1989年的洛马普里塔地震、1994年的北岭地震、1995年的兵库县南部地震和2001年的Nisqually地震。这种破坏限制了受影响社区开展应急行动的能力，减缓了恢复速度，并使有限的灾后重建和发展资源紧张。许多人推测，如果在这些地震之前对桥梁进行大规模的地震测试，这种破坏是可以避免的。幸运的是，在过去的二十年中，有大量的实验数据可以帮助改进基于桥梁构件准静态、伪动态和动态测试的设计、评估和改造方法。然而，这些桥柱的动力测试都是使用大幅缩小（十分之一到四分之一）的样本进行的。由于许多重要的行为模式（剪切、锚固和断裂）在缩小比例模型中不能很好地重现，地震工程界高度重视对桥梁柱进行真实的全尺寸振动台试验。最近在日本三木兵库县地震工程研究中心建造的地球防御（E-Defense）振动台使这样的实验成为可能。日本研究人员正在迅速推进使用E-Defense设施进行全尺寸桥柱和系统的研究。在2007年和2008年期间，他们将使用E-Defense对大约七个全尺寸钢筋混凝土桥柱进行一系列实验，这些桥柱代表了日本过去和现在的设计和施工实践。虽然这些测试将提供全尺寸柱动态行为的基本数据，但这些数据本身对美国工程界的有用性并不是最佳的。该项目为美国研究人员、从业人员和学生提供了一个参与这些实验的规划、实施、分析和解释的特殊机会。日本的规划工作非常先进，正在调动大量资源进行测试。美国已经与日本调查小组建立了强有力的合作关系，这使这个项目成为可能。这项研究将获得、解释和传播全尺寸桥梁柱的第一个振动台结果。将美国和日本样品的结果与过去的测试结果和分析模拟结果进行比较，将为缩小比例模型和在改变应变速率下进行的测试的充分性提供急需的评估。根据观察到的性能，比较美国和日本的设计实践将为桥梁行为提供新的见解。它将提供所需的缺失数据，以增加分析方法的信心，并验证（或改进）当前的设计方法。这项研究是全国联邦和州桥梁机构和行业的高度优先事项。计划的成果传播和预期的教员、学生、专业人员和其他人员的大量交流将扩大该项目的影响。

The goals of this Small Grant for Exploratory Research (SGER) project are to: (1) provide the nucleus around which other investigators, practitioners, and funding agencies can participate; (2) actively collaborate in the planning of the E-Defense bridge column test program; (3) compile and distribute (in accordance with NEES Consortium, Inc., and E-Defense policies) data from the entire test series, including archival in the NEES data repository; (4) conduct a series of experiments on full-scale bridge columns detailed consistent with current U.S. design practices; (5) interpret these data in terms of other data from the E-Defense test program, as well as from previous reduced-scale tests in the United States; (6) carry out numerical simulations using advanced physics-based models as well as simpler phenomenological models of the type used in design practice; (7) evaluate current design and analysis practices in view of these tests and analyses; and (8) widely disseminate results.Major transportation structures, such as bridges, have suffered tremendous damage in recent earthquakes, as observed during the 1989 Loma Prieta, 1994 Northridge, 1995 Hyogo-Ken Nanbu, Japan, and 2001 Nisqually earthquakes. Such damage limits the ability of the affected community to conduct emergency response operations, slows recovery, and strains the limited resources available for post-event reconstruction and development. Many have conjectured that such damage could have been avoided had large-scale seismic tests been done on bridges prior to these earthquakes. Fortunately, considerable experimental data has become available during the past two decades to help improve design, evaluation, and retrofit methods based on quasi-static, pseudo-dynamic and dynamic tests of bridge components. However, these dynamic tests of bridge columns have all been conducted using substantially reduced (one-tenth to one-quarter) scale specimens. Because many important modes of behavior (shear, anchorage, and fracture) do not reproduce well in reduced scale models, the earthquake engineering community has placed high priority on carrying out realistic, full-scale shaking table tests of bridge columns. The recent construction of the Earth Defense (E-Defense) shake table at the Hyogo Earthquake Engineering Research Center in Miki, Japan makes such experiments now feasible. Japanese researchers are moving ahead rapidly to conduct research on full-scale bridge columns and systems using the E-Defense facility. During 2007 and 2008, they will use E-Defense to conduct a series of experiments on approximately seven full-scale reinforced concrete bridge columns representative of past and current Japanese design and construction practices. While these tests will provide fundamental data on the dynamic behavior of full-scale columns, the usefulness of this data by itself to the U.S. engineering community is not optimal.This project responds to an exceptional immediate opportunity for U.S. researchers, practitioners, and students to participate in the planning, conduct, analysis and interpretation of these experiments. Planning in Japan is well advanced, and significant resources are being mobilized to carry out the tests. The strong U.S. collaboration already established with the Japanese team of investigators makes this project feasible. This investigation will obtain, interpret and disseminate the first shake table results for full-scale bridge columns. Comparison of results for the U.S. and Japanese specimens with past tests and with analytical simulations will provide a critically needed assessment of the adequacy of reduced-scale models and tests conducted at altered strain rates. Comparison of U.S. and Japanese design practices in light of observed performance will provide new insights into bridge behavior. It will provide missing data needed to increase confidence in analysis methods and validate (or improve) current design methods. This research is of high priority nationally to federal and state bridge agencies and industry.The impact of the project will be broadened by the planned dissemination of results and by the substantial anticipated exchange of faculty members, students, professionals, and others.