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 However, its potential cannot be fully realized due to current outdated and prescriptive design criteria.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压碎性能极限。Hines，Tufts UniversityMotivation& Scope：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，在中等地震区的结构墙中使用明显较轻的构件是可行的。最近的研究空心墩的抗震设计提供了新的见解，准确评估弹性和非弹性腹板压碎剪切能力的结构墙与边界元素。延性剪切破坏，表现为腹板压碎破坏或在相对较高的位移延性水平下横向钢筋屈服，允许容易修复，因为对边界元件的损坏可以是最小的。高强度混凝土的出现引起了人们极大的兴趣，因为它可以提供具有成本效益的抗震设计。然而，由于目前过时和规范的设计标准，其潜力无法充分发挥。合理的评估模型表明，腹板压碎与混凝土抗压强度呈线性关系，表明随着混凝土强度的增加，更轻构件的抗剪能力有了新的可能性。本项目将通过建立结构墙的非弹性腹板压碎极限来验证这一承诺。目的：本项目的目标是研究和建立合理的性能水平，用于发展基于延性剪切破坏机制的高强混凝土（HSC）结构墙的抗震评估和设计方法。具体而言，该项目将：（1）调查并确定中等延性下HSC结构墙的腹板压碎性能限值，（2）调查空心墩背景下结构墙组件的双向抗震性能，（3）开发具有边界单元的结构墙的分析建模和分析程序，以及（4）开发HSC结构墙的简单评估模型。研究目标将通过综合实验和分析研究来实现。 第一部分的实验研究将集中在确定可靠的界限，腹板挤压破坏的延性剪切反应在HSC结构墙通过8准静态单调和循环试验1/4规模的墙壁与混凝土强度为34，69，103，和137 MPa。平行分析调查将侧重于通过三维非线性有限元模型和更简单的截面分析，开发和验证在其主方向和对角方向加载的结构墙的评估工具。利用改进的评估模型，两个1/4比例的HSC（137 MPa）墙组件类似于空心墩将设计和双向加载下的测试。将设计一个组件，以在低延性水平下获得腹板挤压破坏，以验证组合载荷下系统的既定限值。第二个单元将被设计为在高延性水平下以延性剪切破坏模式破坏。传统和先进的非接触应变测量将与分析结果相关联，从根本上了解相关的变形极限。合理的，但简单的，评估模型将开发提供设计人员与实用的工具，设计的HSC结构墙可靠的延性剪切破坏模式。将建立一个网站，向研究人员、设计人员、教育工作者和学生传播研究结果。将通过PI积极参与技术委员会来实现向实践的过渡。NEES用途：该研究计划将战略性地联合收割机结合密歇根州立大学民用基础设施实验室的实验资源，进行所需的常规伪静态调查，以及明尼苏达大学双子城分校的多轴子装配测试（MAST）NEES设施提供的新能力，协作元素：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咨询委员会的协助。知识优势：对地震设计原则的了解越来越多，以至于地震安全很少受到损害。相反，材料科学的进步，对结构行为的了解增加以及进行复杂计算模拟的可用性表明，从当前的保守主义转向改善即时和长期成本以及在不牺牲安全性的情况下增强结构优雅性的适当时机。建立高强度混凝土结构墙的性能极限表现在替代延性破坏模式，预计将有助于在地震工程设计的下一阶段薄腹板元件和系统的基础。广泛的影响：该项目将整合研究工作的教育任务的合作机构，通过培养地震工程知识，通过：（a）培训两名研究生，（B）为代表性不足群体的两名本科生提供研究经验，（c）加强教学课程。将坚决尝试利用大学课程招收代表性不足的研究生。研究将有助于下一阶段的抗震设计的基础，从保守的方法，通过建立合理的性能限制，在延性剪切破坏模式的HSC迁移。