NEESR-II: Inelastic Web Crushing Performance Limits of High-Strength-Concrete Structural Walls

NEESR-II：高强混凝土结构墙的非弹性腹板破碎性能极限

• 批准号: 0530634
• 负责人: Rigoberto Burgueno
• 金额: --
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0530634&HistoricalAwards=false
• 关键词: NEESR; II; Inelastic; Web; Crushing

AbstractNEESR-II: Inelastic Web Crushing Performance Limits of High-Strength-Concrete Structural WallsPI: Rigoberto Burgueno, Michigan State University; Co-PI: Eric M. Hines, Tufts UniversityMotivation & Scope: Significantly lighter members for structural walls in moderate seismic zones are a viable possibility by using high-strength concrete and incorporating ductile shear failures as a new genre of ductile failure mechanisms. Recent research on the seismic design of hollow piers has provided new insights on the accurate assessment of elastic and inelastic web crushing shear capacity of structural walls with boundary elements. Ductile shear failures, displayed as web crushing failures or yielding of the transverse reinforcement at relatively high levels of displacement ductility, allow for easy repair since damage to the boundary elements can be minimal. The advent of high-strength concrete has generated great interest in the promise that it may provide for cost-effective seismic design. However, its potential cannot be fully realized due to current outdated and prescriptive design criteria. Rational assessment models show that web crushing is linearly related to concrete compressive strength, indicative of new possibilities for increased shear capacities of lighter members with increased concrete strength. This project will verify this promise by establishing the inelastic web crushing limits for structural walls. Objectives: The goal of this project is to investigate and establish rational performance levels for the development of seismic assessment and design approaches to high-strength-concrete (HSC) structural walls based on ductile shear failure mechanisms. Specifically, the project will: (1) investigate and establish the web-crushing performance limits of HSC structural walls at moderate ductility, (2) investigate the bi-directional seismic performance of structural wall assemblies in the context of hollow piers, (3) develop analytical modeling and analysis procedures for structural walls with boundary elements, and (4) develop simple assessment models for HSC structural walls.Approach: The research objectives will be achieved through integrated experimental and analytical investigations. The first part of the experimental investigation will focus on the determination of dependable limits to web crushing failures for ductile shear response in HSC structural walls through 8 quasi-static monotonic and cyclic tests on 1/4-scale walls with concrete strengths of 34, 69, 103, and 137 MPa. Parallel analytical investigations will focus on the development and validation of assessment tools for structural walls loaded in their principal and diagonal directions through 3D nonlinear finite element models and simpler sectional analyses. Using the improved assessment models, two 1/4-scale HSC (137 MPa) wall assemblies analogous to hollow piers will be designed and tested under bidirectional loading. One assembly will be designed to obtain a web crushing failure at low ductility levels to validate the established limits for systems under combined loading. The second unit will be designed to fail in a ductile shear failure mode at high ductility levels. Conventional and advanced non-contact strain measurements will be correlatedwith analysis results to fundamentally understand the associated deformation limits. Rational, yet simple, assessment models will be developed to provide designers with practical tools for the design of HSC structural walls with reliable ductile shear failure modes. A website will be developed to disseminate results to researchers, designers, educators and students. Transition to practice will be pursed by active participation of the PIs in technical committees.NEES Use: The research plan will strategically combine the experimental resources of Michigan State University's Civil Infrastructure Laboratory to conduct the required conventional pseudo-static investigations, and the new capabilities provided by the Multi-Axial Subassemblage Testing (MAST) NEES facility at the University of Minnesota-Twin Cities to evaluate the bi-directional performance of structural wall assemblies.Collaborative Elements: The research team consists of collaboration between Michigan State University and Tufts University, which combines strengths and resources in experimentation, analysis, design practice and education. The research effort will be assisted by an external advisory board with significant project-related experience.Intellectual Merit: Increased understanding of earthquake design principles has become so robust that seismicsafety is rarely compromised. Rather, advancement in materials science, increased knowledge on structural behavior and the availability to perform complex computational simulations indicate a proper moment to migrate from current conservatism towards improvements in immediate and long-term cost and enhancement of structural elegance without sacrificing safety. The establishment of performance limits for high-strength-concrete structural walls behaving in alternative ductile modes of failure is expected to contribute to the groundwork of the next stage in earthquake engineering design of thin-webbed elements and systems.Broad Impact: The project will integrate the research efforts to the educational missions of both collaborative institutions by fostering knowledge in earthquake engineering through: (a) training of two graduate students, (b) research experiences for two undergraduates from underrepresented groups, and (c) enhanced teaching curricula. A determined attempt will be made to recruit underrepresented graduate students using university programs. The research will contribute to the groundwork of the next stage in seismic design by migrating from conservative approaches through establishment of rational performance limits for HSC in ductile shear failure modes.

摘要NEESR-II：高强度混凝土结构墙的非弹性腹板破碎性能极限PI：Rigoberto Burgueno，密歇根州立大学；联合首席研究员：Eric M. Hines，塔夫茨大学动机和范围：通过使用高强度混凝土并将延性剪切破坏作为一种新的延性破坏机制，在中度地震区使用明显更轻的结构墙构件是可行的。最近对空心桥墩抗震设计的研究为精确评估具有边界单元的结构墙的弹性和非弹性腹板压碎剪切能力提供了新的见解。延性剪切失效表现为腹板压碎失效或横向钢筋在相对较高水平的位移延展性下屈服，因此易于修复，因为对边界元件的损坏可以最小化。高强度混凝土的出现引起了人们的极大兴趣，因为它有望提供具有成本效益的抗震设计。然而，由于当前过时的规定性设计标准，其潜力无法完全发挥。合理的评估模型表明，腹板压碎与混凝土抗压强度线性相关，这表明随着混凝土强度的增加，轻质构件的剪切能力增加的新可能性。该项目将通过建立结构墙的非弹性腹板破碎极限来验证这一承诺。目标：该项目的目标是调查并建立合理的性能水平，以开发基于延性剪切破坏机制的高强度混凝土（HSC）结构墙的抗震评估和设计方法。具体来说，该项目将：(1) 研究并确定中等延展性下 HSC 结构墙的腹板破碎性能极限，(2) 研究空心墩背景下结构墙组件的双向抗震性能，(3) 开发具有边界元的结构墙的分析建模和分析程序，(4) 开发 HSC 结构墙的简单评估模型。 方法：研究目标将通过集成来实现 实验和分析研究。 实验研究的第一部分将侧重于通过对混凝土强度为 34、69、103 和 137 MPa 的 1/4 比例墙进行 8 次准静态单调和循环测试，确定 HSC 结构墙延性剪切响应的腹板压碎失效的可靠极限。并行分析研究将侧重于通过 3D 非线性有限元模型和更简单的截面分析，开发和验证结构墙在主方向和对角线方向上加载的评估工具。使用改进的评估模型，将设计两个类似于空心墩的 1/4 比例 HSC (137 MPa) 墙组件，并在双向加载下进行测试。一种组件将被设计为在低延展性水平下获得腹板压碎失效，以验证组合负载下系统的既定限制。第二个单元将设计为在高延展性水平下以延性剪切破坏模式失效。传统和先进的非接触式应变测量将与分析结果相关联，以从根本上了解相关的变形限制。将开发合理而简单的评估模型，为设计人员提供实用工具，用于设计具有可靠延性剪切破坏模式的 HSC 结构墙。将开发一个网站，向研究人员、设计师、教育工作者和学生传播研究结果。 PI 积极参与技术委员会将促进向实践的过渡。 NEES 使用：该研究计划将战略性地结合密歇根州立大学土木基础设施实验室的实验资源，以进行所需的常规伪静态研究，以及明尼苏达大学双城分校多轴组件测试 (MAST) NEES 设施提供的新功能，以评估双向性能 合作元素：该研究团队由密歇根州立大学和塔夫茨大学合作组成，结合了实验、分析、设计实践和教育方面的优势和资源。研究工作将得到具有丰富项目相关经验的外部顾问委员会的协助。智力优势：对地震设计原理的理解不断加深，地震安全性很少受到影响。相反，材料科学的进步、结构行为知识的增加以及执行复杂计算模拟的可用性表明，现在是从当前的保守主义转向改善近期和长期成本以及在不牺牲安全性的情况下增强结构优雅的适当时机。建立高强度混凝土结构墙在替代延性失效模式下的性能极限，预计将有助于为下一阶段的薄腹板构件和系统地震工程设计奠定基础。 广泛影响：该项目将通过以下方式培养地震工程知识，将研究工作与两个合作机构的教育使命结合起来：(a) 培训两名研究生，(b) 研究经验 为两名来自代表性不足群体的本科生提供帮助，(c) 加强教学课程。我们将坚决尝试利用大学课程招收代表性不足的研究生。该研究将从保守方法转变为在延性剪切破坏模式下建立 HSC 的合理性能限制，为下一阶段的抗震设计奠定基础。