NEESR-CR: Full-Scale RC and HPFRC Frame Subassemblages Subjected to Collapse-Consistent Loading Protocols for Enhanced Collapse Simulation and Internal Damage Characterization

该奖项是NSF 09-524项目征集“小乔治·E·布朗地震工程模拟(NEES)研究网络(NEESR)”竞赛的结果，其中包括德克萨斯大学阿灵顿分校(牵头机构)、加州州立大学奇科分校(分奖)、伊利诺伊大学厄巴纳-香槟分奖(分奖)和明尼苏达大学(分奖)。该项目将利用明尼苏达大学多轴组件测试(MAST)实验室的NEES设备现场。钢筋混凝土(RC)结构构成了世界上大量的建筑物和桥梁。钢筋混凝土结构的抗倒塌能力尚未得到很好的理解，尽管抗倒塌能力对建筑物使用者在地震中的生命安全至关重要。其中一个主要问题是，目前可用的实验测试数据不足以让研究人员全面了解建筑物的倒塌行为，并开发准确的计算机模拟模型来预测建筑物在地震中何时会倒塌。这项研究的目的是增进对现代钢筋混凝土框架建筑和高性能纤维混凝土框架建筑在极端地震作用下的倒塌行为和安全性的认识。这项研究项目涉及测试一套全面的全尺寸RC组件和组件，直到坍塌(几乎所有现有的测试数据都不到倒塌)；这套全面的测试是专门为更好地了解倒塌行为和创建改进的计算机模拟模型来预测RC建筑的倒塌安全而设计的。为了更好地了解材料内部损伤是如何在小范围内发展的，在测试过程中将利用先进的成像技术(超声波断层扫描)来表征内部损伤的发展过程。为了更好地了解全尺寸钢筋混凝土建筑的倒塌行为，将开发改进的计算机模拟模型，并将直接模拟钢筋混凝土建筑模型的倒塌。知识价值：预计将做出以下技术贡献：(1)新的校准RC/HPFRC构件模型，(2)对用RC和HPFRC材料建造的RC框架建筑的抗倒塌性能的新理解；(3)可用作现场结构评估工具的内部成像技术的发展；以及(4)对反复荷载作用下RC柱和板-梁-柱连接的内部损伤发展和机理的理解。更广泛的影响：这项研究的结果将为新建造的RC弯矩框架以及由新兴的高性能材料(HPFRC)建造的弯矩框架的倒塌评估提供全面的信息。这些信息对于支持HPFRC的广泛使用是必要的。先进的混凝土结构成像技术的发展将提供新的诊断能力，以确定混凝土构件内的结构损伤，例如在地震发生后立即确定。在这项研究中开发的倒塌模拟和成像技术将被整合到教育工具中，向本科生介绍地震工程研究、地震效应的重要性以及建筑物在倒塌水平地面运动下的行为。此外，加州州立大学奇科分校的本科生将直接参与这项研究。跨学科工作计划将促进专业准备的研究生的发展，他们接触到广泛的交叉技术。该项目的数据将被存档，并通过NEES数据库向公众提供。该奖项是国家减少地震灾害计划(NEHRP)的一部分。

This award is an outcome of the NSF 09-524 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes the University of Texas at Arlington (lead institution), California State University at Chico (subaward), University of Illinois at Urbana-Champaign (subaward), and the University of Minnesota (subaward). The project will utilize the NEES equipment site at the University of Minnesota, the Multi-Axial Subassemblage Testing (MAST) Laboratory. Reinforced concrete (RC) structures comprise a large number of the buildings and bridges around the world. The collapse resistance of RC structures is not well understood, even though the collapse resistance is fundamental to the life-safety of building occupants during earthquakes. One of the primary problems is that currently available experimental test data are insufficient to allow researchers to comprehensively understand the collapse behavior of a building and develop accurate computer simulation models to predict when a building would collapse in an earthquake. The objective of this research is to advance knowledge about the collapse behavior and safety of both modern RC frame buildings and high performance fiber reinforced concrete (HPFRC) frame buildings when subjected to extreme earthquakes. This research project involves testing a comprehensive set of full-scale RC components and subassemblages all the way to collapse (nearly all currently available test data stop short of collapse); this comprehensive set of tests has been specifically planned for the purpose of better understanding collapse behavior and creating improved computer simulation models to predict the collapse safety of RC buildings. To improve understanding of how internal damage develops at small scales within the materials, advanced imaging technology (ultrasonic tomography) will be utilized during testing to characterize the progression of internal damage. To improve understanding of the collapse behavior of full large-scale RC buildings, improved computer simulation models will be developed and the collapse of RC building models will be directly simulated. Intellectual Merit: The following technical contributions are anticipated: (1) new calibrated RC/HPFRC component models, (2) new understanding of collapse resistance behavior of RC frame buildings constructed with RC and HPFRC materials; (3) development of internal imaging technology that could be used as an on-site structural assessment tool; and (4) understanding of the internal damage development and mechanisms for RC columns and slab-beam-column connections subjected to cyclic loading. Broader Impacts: Results from this study will provide comprehensive information for collapse assessment of newly constructed RC moment frames, as well as moment frames constructed from an emerging high performance material (HPFRC). Such information will be necessary to support widespread use of HPFRC. The development of advanced imaging technology for concrete structures will provide new diagnostic capability to ascertain structural damage within concrete members, for example immediately after an earthquake event. The collapse simulation and imaging techniques developed in this research will be incorporated into educational tools to introduce undergraduate students to earthquake engineering research, the significance of earthquake effects, and the behavior of building structures subjected to collapse-level ground motions. Additionally, undergraduate students at the California State University at Chico will directly participate in the research. The interdisciplinary work plan will promote the development of professionally prepared graduate students who have exposure to a broad range of cross-cutting technologies. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).