Experimental and Analytical Investigations of Shake Table Tests of a Reinforced Concrete Structure at the E-Defense Shake Table Facility

2010年12月，在日本三木市的国家地球科学与灾害研究所（NIED） E-Defense震动台设施中，两个全尺寸的四层钢筋混凝土建筑结构在不断增加的多向地震激励下接近倒塌。国家科学基金会1110860奖的首席研究员和几位美国研究人员与日本研究人员合作，对样品进行仪器测量并观察性能。结构中的梁、柱和板均按预期运行。然而，剪力墙和梁柱节点即使按照现行的地震工程实践设计，也表现出严重的破坏和整体性损失。实验程序提供了丰富的数据来研究现有分析工具的准确性。目前的分析工具是基于单个结构部件的拟静力实验研究来校准的。因此，结构工程领域采用了许多外推法来形成完整结构体系的分析模型。这种外推的明显后果是无法验证系统级分析结果的有效性。测试系列的记录数据提供了一个独特的机会来研究当前使用的分析工具的准确性，确定参数假设，并改进结构系统的分析方法。通过这个项目，将提供关键的指导，为这类结构制定分析模型。就测试全尺寸建筑物地震运动的能力而言，日本NIED/E-Defense设施的振动台在世界上没有类似的设备。该系列试验是在一个全尺寸的四层钢筋混凝土建筑结构上进行的，该结构密切反映了当前美国的抗震设计实践。该系列测试是迄今为止唯一一个在控制条件下经受真实地震事件的全尺寸、现代、抗震设计的钢筋混凝土结构。结构的性能比预期的要差，这引起了人们对当前抗震设计和施工实践是否足够的严重质疑。本项目将揭示这种性能的原因，并提供改进设计实践的建议。研究目标将在与日本研究人员的密切合作下实现。将向美国和日本的期刊提交一份报告和出版物，向广大读者介绍主要成果。首席研究员将利用该项目加强与日本研究人员和E-Defense中心的联系。德克萨斯大学的工程专业研究生将受益于课堂指导和参与研究，包括前往日本向地震工程领域前沿的日本研究人员学习。

In December 2010, two full-scale four-story reinforced concrete building structures were tested at the National Research Institute for Earth Science and Disaster (NIED) E-Defense shake table facility in Miki City, Japan under increasing multi-directional seismic excitations to near collapse. The principal investigator and several U.S. researchers under NSF award 1110860 collaborated with Japanese investigators to instrument the specimens and observe the performance. Beams, columns, and slabs in the structure performed as expected. However shear walls and beam-column joints showed severe damage and loss of integrity even though designed according to current earthquake engineering practice. The experimental program presents wealth of data to study the accuracy of current analytical tools. Current analytical tools are calibrated based on pseudo-static experimental investigations of individual structural components. The structural engineering field has therefore resorted to a number of extrapolations to form analytical models of complete structural systems. The obvious consequence of such extrapolations is an inability to verify the validity of system level analytical results. The recorded data of test series presents a unique opportunity to study the accuracy of currently used analytical tools, identify parametric assumptions, and improve on analytical method for structural systems. Through this project critical guidance will be delivered on formulating analytical models for this type of structures.The shake table at the Japanese NIED/E-Defense facility has no counterpart in the world in terms of capacities of testing full-scale buildings for earthquake motions. The test series were performed on a full-scale four-story reinforced concrete building structure that reflected closely current U.S. practices for earthquake design. This test series is the only one to date of a full-scale, modern, seismically designed reinforced concrete structure subjected under controlled conditions to a real seismic event. The performance of structures was worse than anticipated, which raises serious questions about the adequacy of current seismic design and construction practices. This project will uncover the causes of this performance and provide recommendations for improvements in design practices. The research objectives will be achieved in close collaboration with Japanese researchers. A report and publications will be submitted to U.S. and Japanese journals to present key results to a broad audience. The Principal Investigator will use this project to strengthen ties with Japanese researchers and the E-Defense center. Graduate engineering students the University of Texas will benefit through classroom instructions and involvement in the research including travel to Japan to learn from Japanese researchers at the forefront of the field of earthquake engineering.