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: 0324542
• 负责人: Roberto Leon
• 金额: $ 21.84万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0324542&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：Leon.格鲁吉亚技术1994年北岭和1995年科比地震表明，需要新的技术和结构配置，以限制破坏钢结构受到中等和大的地面运动。在这种情况下，需要提供额外的刚度，以现代框架配置是明确的，导致新的兴趣在支撑框架配置。然而，支撑框架被认为不是很有韧性，因为单个支撑的屈曲会很快导致层间结构的形成。现代结构对刚度和延性的额外需求由于结构更轻、更紧凑的抗侧力系统和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，将开发和测试一种新的支撑系统，称为拉链框架，作为这项拟议工作的一部分。这一提议是解决这一问题的两阶段合作办法的第一阶段。在第一阶段的实验部分，四个实验室（格鲁吉亚技术（GT），美国。在布法罗，美国加州大学伯克利分校（UCB）和美国大学伯克利分校（U。位于博尔德（CU）的科罗拉多大学）将对整个系统、部件和单个元素的行为进行研究。这些将在各种荷载状态下进行测试，从振动台测试到准静态测试，以提供全面的数据，作为设计建议的基础。在第一阶段的分析部分，上述四所大学，加上佛罗里达A M（FAMU）和伦敦帝国学院（IC），将进行广泛的分析研究，以提供（1）基础和补充实验工作，（2）NEES联盟的NEESgrid部分的测试平台，以及（3）用于设计的新的，简化的和全面的模型。作为第一阶段的最后一项任务，GT和FAMU的研究人员将制定第二阶段的提案，该提案将涉及在支撑钢结构中使用先进材料和主动控制。在拟议的研究中的智力价值是，它将提供一个独特的数据库的拉链框架的行为信息，并将提供一个新的一类支撑系统的概念验证研究的结果。此外，该研究将导致分析模型的发展，可以实施到现有的地震分析程序。该研究将开发分析工具和方法，使执业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联盟提供初步调试研究，特别是测试NEESgrid系统的灵活性和鲁棒性。此外，它将为未来的NEES合作提供后勤和技术方面的宝贵经验。该项目将连接三个NEES站点，一个完善的计划（GT），一个开发计划（FAMU）和国际合作伙伴（IC），作为未来大挑战合作的测试案例。该项目分为两个阶段，以便两名年轻的远程研究人员（GT的DesRoches博士和FAMU的Abdullah博士）将从第一阶段的工作中受益，以发展他们在第二阶段所需的伪动态和振动台测试方面的技术专长。这旨在成为未来NEES项目的一个模式，其中来自远程站点的研究人员将能够从现有研究人员/站点获得宝贵的经验和指导。这项研究在很大程度上取决于五个地点的研究人员之间的合作。为了最大限度地发挥该项目的潜在影响，提出了该项目的一个强有力的教育组成部分。为了补充合作研究计划，其中包括一个非常大的研究生交流，一个NEES本科研究计划将开发。该计划将包括三个组成部分;在网站的本科生研究经验，夏季本科生研究交流计划，以及为期2天的学生研讨会。来自传统上代表性不足的群体的学生将专门针对本科研究计划。拟议的研究的更广泛的影响是，它将提供重要的信息，为设计界的性能支撑框架结构。此外，拟议的研究将作为未来使用NEES进行合作研究的模型。