NEESR-CR: Unbonded Post-Tensioned Rocking Walls for Seismic Resilient Structures

NEESR-CR：用于抗震结构的无粘结后张法摇墙

• 批准号: 1041650
• 负责人: Sri Sritharan
• 金额: $ 119.99万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1041650&HistoricalAwards=false
• 关键词: NEESR; CR; Unbonded; Post; Tensioned

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 Iowa State University (ISU) as well as two University of Minnesota campuses: Twin Cities (UMN) and Duluth (UMD). This project will utilize the NEES facilities located at UMN and the University of Nevada at Reno.The motivation for this research is that damage caused by earthquakes, and the subsequent economic losses, underscore the need to focus on developing earthquake resilient buildings. One method of achieving resilient buildings is to design them with self-centering structural systems to resist earthquake lateral loads. Using unbonded post-tensioning tendons, a cost-effective, self-centering wall system known as PreWEC (i.e., Precast Wall with two End Columns) was developed at ISU, which has been proven analytically and experimentally to have excellent seismic performance with minimal structural damage. In this system, as well as in single rocking walls (SRWs) designed with unbonded post-tensioning, the response is dominated by a rocking mode. However, the energy loss caused by the wall impacting the foundation during rocking has not been given consideration in design due to lack of knowledge on this subject. Significant evidence suggests that this mechanism alone may be sufficient to dissipate the seismic energy. Furthermore, the resilience of a building containing rocking walls is also dependent on the behavior of surrounding structural components, especially floors and gravity columns, and their interactions with the seismic resistant systems. To ensure a fully resilient structure, these interactions should be addressed by understanding the wall-floor connection responses. Intellectual Merit: In collaboration with E-Defense in Japan and researchers at the University of Auckland in New Zealand, the intellectual merit of this project is the development of seismic resilient building solutions utilizing the fundamental characteristics of seismic rocking of both SRWs and PreWECs. By involving an international, cross-disciplinary team of experts and two NEES facilities, the project will accomplish this goal by completing the following objectives: 1) understand the fundamental characteristics of seismic rocking of self-centering walls through NEES/international tests, thereby identifying different energy dissipation sources (i.e., energy loss due to impact, viscous damping and hysteretic damping); 2) develop suitable connections between rocking walls and floors, and quantify the wall-floor-column interactions using large-scale tests; 3) ensure safety of the rocking systems through sufficient anchorage of the unbonded tendons; 4) design seismic resilient structures; 5) improve numerical simulation of buildings designed with rocking walls and different floor systems; 6) formulate design guidelines; and 7) educate students, practitioners, and others (e.g., policymakers) on the significance of the proposed study.Broader Impacts: This award also has several broader impacts. First, it offers several unique opportunities for graduate and undergraduate students from diverse populations to participate and collaborate with an international team of researchers in a distributed NEES environment. Second, it promotes the participation of underrepresented students in civil engineering and introduces K-12 students to the new NEES collaboration model and benefits of rocking walls in seismic resistant design. The research team will contribute to Project Lead the Way (PLTW), a program designed to prepare middle and high school students for college-level engineering education by exposing them to engineering courses. UMD will pilot the proposed PLTW program at schools in northern Minnesota, including tribal schools. Next, a unique, team-oriented course module will be developed by integrating the research outcomes so that it can be used for instruction at the graduate and undergraduate levels. This module will be made available to the earthquake engineering community through NEEShub. Using the planned NEES collaboration within the project, the project team will also contribute to advancing NEES telepresence technologies. Finally, the proposed project will enhance research and education at the three participating institutions, which includes a predominantly undergraduate university. All anticipated project outcomes will ultimately produce new basic knowledge needed to design safer, more resilient buildings in seismic regions and thus contribute to seismic hazard mitigation in the United States and around the world. 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).

该奖项是NSF 09-524计划招标的结果“ George E. Brown，Jr。Jr.地震工程模拟网络（NEES）Research（NEESR）”竞争，包括爱荷华州立大学（ISU）以及两个明尼苏达大学校园：Twin Cities：Twin Cities（UMN）和Duluth（Umd）。该项目将利用位于UMN和内华达大学里诺大学的NEES设施。这项研究的动机是，地震造成的损害以及随后的经济损失，强调了需要专注于开发地震弹性建筑物。 实现弹性建筑物的一种方法是使用自动核心结构系统设计它们，以抵抗地震横向负载。在ISU上开发了一种具有成本效益的，自我为中心的壁系统（即带有两个末端柱的预制壁）的成本效益，以自我为中心的墙壁系统，在ISU上开发了该系统，该系统已在分析和实验上经过证明，具有极好的地震性能，具有最小的结构损害。在此系统中，以及在设计有无粘性后张紧的单个摇摆壁（SRW）中，该响应以摇摆模式为主导。但是，由于缺乏对该主题的知识，尚未考虑摇摆过程中墙壁影响基础造成的能量损失。 大量证据表明，仅这种机制就足以消散地震能。此外，包含摇摆壁的建筑物的弹性还取决于周围结构组件的行为，尤其是地板和重力柱，以及它们与地震抗性系统的相互作用。为了确保完全弹性的结构，应通过了解墙板连接响应来解决这些相互作用。知识分子的优点：与日本的电子防御和新西兰奥克兰大学的研究人员合作，该项目的知识分子是利用SRW和Prewecs地震摇摆的基本特征的地震弹性建筑解决方案的发展。通过参与国际，跨学科的专家和两个NEES设施，该项目将通过完成以下目标来实现这一目标：1）了解通过NEES/国际测试对自动核心墙壁的地震摇摆的基本特征，从而确定不同的能量耗散来源（即，由于影响，影响，影响，可影响，粘贴型damp damp damping damping damping damping damping damping damp and settic damping damps）; 2）在摇摆壁和地板之间建立合适的连接，并使用大规模测试量化墙壁地板的相互作用； 3）通过足够的无粘结肌腱锚固确保摇动系统的安全； 4）设计地震弹性结构； 5）改善使用摇摆墙和不同地板系统设计的建筑物的数值模拟； 6）制定设计指南； 7）教育学生，从业人员和其他人（例如政策制定者）​​就拟议的研究的重要性进行教育。Boader的影响：该奖项也具有更广泛的影响。首先，它为来自不同人群的研究生和本科生提供了一些独特的机会，可以与国际研究人员合作，并在分布式NEES环境中合作。其次，它促进了代表性不足的学生参与土木工程的参与，并向K-12学生介绍了新的NEES协作模型，并在地震抗性设计中摇摆墙的好处。 研究团队将为项目领导（PLTW）做出贡献，该计划旨在通过将他们暴露于工程课程中，为中学生和高中生准备大学级工程教育。 UMD将在明尼苏达州北部的学校（包括部落学校）试行拟议的PLTW计划。接下来，将通过整合研究成果来开发一个独特的面向团队的课程模块，以便在研究生和本科级别的教学中使用它。该模块将通过Neeshub提供给地震工程社区。使用计划的NEES协作，项目团队还将为NEES Tepresence Technologies提供贡献。最后，拟议的项目将在包括本科大学的三个参与机构中加强研究和教育。 所有预期的项目成果最终都将产生在地震地区设计更安全，更具弹性的建筑所需的新基本知识，从而有助于美国和世界各地的地震危害减轻。 该项目的数据将通过NEES数据存储库进行存档并提供给公众。 该奖项是国家地震危害计划（NEHRP）的一部分。