Collaborative Research: Behavior of Braced Steel Frames With Innovative Bracing Schemes - A NEES Collaboratory Project

合作研究：采用创新支撑方案的支撑钢框架的行为 - NEES 合作项目

• 批准号: 0639997
• 负责人: P. Benson Shing
• 金额: $ 5.79万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0639997&HistoricalAwards=false
• 关键词: Collaborative; Research; Behavior; Braced; Steel

PI: Leon. Georgia TechThe 1994 Northridge and 1995 Kobe earthquakes showed that new technologies and structural configurations are needed to limit damage to steel structures subjected to moderate and large ground motions. In this context, the need to provide additional stiffness to modern frame configurations is clear, leading to a renewed interest in braced frame configurations. Braced frames, however, are regarded as not being very ductile because buckling of individual braces quickly leads to formation of story mechanisms. The additional need for stiffness and ductility for modern structures is compounded by the trends towards lighter structures, more compact lateral-load resisting systems and the advent of performance-based design. To solve the traditional problems associated with conventional braced frames, a new class of bracing systems, known as a zipper frames, will be developed and tested as part of this proposed work. This proposal represents the first phase of a two-phase collaborative approach to the problem. In the experimental portion of the first phase, four laboratories (Georgia Tech (GT), U. at Buffalo (UB), U. of California at Berkeley (UCB), and the U. of Colorado at Boulder (CU)) will conduct studies on the behavior of whole systems, subassemblages, and individual elements. These will be tested under a variety of load regimes, ranging from shake table tests to quasi-static ones, in order to provide comprehensive data on which to base design recommendations. In the analytical part of the first phase, the four universities listed above, plus Florida A&M (FAMU) and Imperial College-London (IC), will conduct extensive analytical studies to provide (1) a basis and a complement to the experimental work, (2) a testbed for the NEESgrid portion of the NEES Consortium, and (3) new, simplified and comprehensive models for use in design. As the final task for the first phase, GT and FAMU researchers will develop the proposal for the second phase, which will deal with the use of advanced materials and active controls in braced steel structures. The intellectual merit in the proposed research is that it will provide a unique database of information on the behavior of zipper frames, and will provide results from proof-of-concept studies on a new class of bracing systems. In addition, the research will lead to the development of analytical models that can be implemented into existing seismic analysis programs. The research will develop analytical tools and methodologies to allow practicing engineers to determine potential benefits of a variety of applications of zipper frames. The project also intends provide initial shakedown studies for the NEES Consortium and in particular to test the flexibility and robustness of the NEESgrid system. In addition, it will provide valuable lessons from both the logistical and technical standpoints for future NEES collaborations. The project will link three NEES sites, one well-established program (GT), one developing program (FAMU) and international partner (IC) as a test case for future grand challenge collaborations. The project has been divided into two phases so that two younger remote researchers (Dr. DesRoches from GT and Dr. Abdullah from FAMU) will benefit from the work on the first phase in order to develop the technical expertise in pseudo-dynamic and shake table testing that they will need for the second phase. This intends to be a model for future NEES projects in which researchers from remote sites will be able to gain valuable experience and mentoring from established researchers/sites. The research proposed depends strongly on the collaboration between researchers at five sites. To fully maximize the potential impact of this project, a strong education component of the program is proposed. To complement the collaborative research program, that includes a very large exchange of graduate students, a NEES undergraduate research program will be developed. The program will consist of three components; an undergraduate research experience at the sites, a summer undergraduate research exchange program, and a 2-day student symposium. Students from traditionally underrepresented groups will be specifically targeted for the undergraduate research program. The broader impact of the proposed research is that is will provide important information for the design community on the performance of braced frame construction. In addition, the proposed study will serve as a model for future collaborative research using NEES.

PI：莱昂。佐治亚理工学院 1994 年的北岭地震和 1995 年的神户地震表明，需要新技术和结构配置来限制钢结构在中度和大规模地面运动中的损坏。在这种情况下，显然需要为现代框架配置提供额外的刚度，这导致人们对支撑框架配置重新产生了兴趣。然而，支撑框架被认为延展性不太好，因为各个支撑的屈曲很快就会导致楼层机构的形成。现代结构对刚度和延展性的额外需求因结构更轻、抗侧向载荷系统更紧凑以及基于性能的设计的出现而变得更加复杂。为了解决与传统支撑框架相关的传统问题，作为这项拟议工作的一部分，将开发和测试一类新型支撑系统，称为拉链框架。该提案代表了解决该问题的两阶段协作方法的第一阶段。在第一阶段的实验部分，四个实验室（佐治亚理工学院（GT）、布法罗大学（UB）、加州大学伯克利分校（UCB）和科罗拉多大学博尔德分校（CU））将进行研究整个系统、子组合和单个元素的行为。这些将在从振动台测试到准静态测试的各种负载情况下进行测试，以便提供作为设计建议基础的全面数据。在第一阶段的分析部分，上述四所大学，加上佛罗里达农工大学（FAMU）和伦敦帝国理工学院（IC）将进行广泛的分析研究，以提供（1）实验工作的基础和补充， (2) NEES 联盟 NEESgrid 部分的测试平台，以及 (3) 用于设计的新的、简化的和综合的模型。作为第一阶段的最终任务，GT 和 FAMU 研究人员将制定第二阶段的提案，该提案将涉及先进材料和主动控制在支撑钢结构中的使用。拟议研究的智力价值在于，它将提供有关拉链框架行为的独特信息数据库，并将提供新型支撑系统概念验证研究的结果。此外，该研究还将开发可应用于现有地震分析程序的分析模型。该研究将开发分析工具和方法，使实践工程师能够确定拉链框架各种应用的潜在好处。该项目还打算为 NEES 联盟提供初步测试研究，特别是测试 NEESgrid 系统的灵活性和稳健性。此外，它还将为未来的 NEES 合作提供后勤和技术方面的宝贵经验教训。该项目将连接三个 NEES 站点、一个成熟项目 (GT)、一个开发项目 (FAMU) 和国际合作伙伴 (IC)，作为未来重大挑战合作的测试案例。该项目分为两个阶段，以便两位年轻的远程研究人员（来自 GT 的 DesRoches 博士和来自 FAMU 的 Abdullah 博士）将从第一阶段的工作中受益，以发展伪动力和振动台方面的技术专长他们需要进行第二阶段的测试。这旨在成为未来 NEES 项目的一个模型，在该项目中，来自远程站点的研究人员将能够从已建立的研究人员/站点获得宝贵的经验和指导。拟议的研究很大程度上取决于五个地点研究人员之间的合作。为了充分发挥该项目的潜在影响，建议该计划包含一个强有力的教育部分。为了补充合作研究计划（包括大量研究生交换），将制定 NEES 本科生研究计划。该计划将由三个部分组成；本科生在这些地点的研究体验、暑期本科生研究交流计划和为期 2 天的学生研讨会。来自传统上代表性不足群体的学生将成为本科研究项目的专门目标。拟议研究的更广泛影响在于，它将为设计界提供有关支撑框架结构性能的重要信息。此外，拟议的研究将作为未来使用 NEES 进行合作研究的模型。