ERI: Segmented Braces for Improved Seismic Performance and Repairability of Concentrically Braced Frames

ERI：分段支撑可提高同心支撑框架的抗震性能和可修复性

• 批准号: 2138912
• 负责人: Andrew Sen
• 金额: $ 20万
• 依托单位: Marquette University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138912&HistoricalAwards=false
• 关键词: ERI; Segmented; Braces; Improved; Seismic

This Engineering Research Initiation (ERI) award will develop a new seismic design approach for steel braced frames using segmented braces configured for rapid post-earthquake repair. Buildings constructed in regions vulnerable to seismic hazards in the United States are designed to remain safe during large earthquakes, but structural components, such as diagonal braces, are designed to sustain damage as they dissipate seismic energy. This building damage may be severe and widespread in earthquake-affected communities, inhibiting the speed or possibility of post-earthquake occupancy, functionality, and repair. Steel braced frames are prevalent in existing building infrastructure across a broad range of uses, including hospitals, schools, offices, and industrial facilities, which are critical for post-earthquake shelter and care of people, distribution of goods, and economic productivity. The segmented bracing scheme will mitigate the impact of seismic damage in these common systems and enhance seismic resiliency by enabling relatively fast, low-cost replacement of the brace midspan segment such that most other system components can be safely retained. Experimental testing will investigate the seismic behavior of segmented braces applied to new construction and repair scenarios. An accompanying computational study will expand these findings to evaluate additional design parameters toward the development of design procedures and modeling recommendations suitable for engineering practice. The research activities will be incorporated into a laboratory experience course module in structural steel design and engage underrepresented groups in engineering through undergraduate research opportunities and outreach programs. This award will contribute to the National Science Foundation role in the National Earthquake Hazards Reduction Program (NEHRP). Project data will be archived and made publicly available in the Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org). Concentrically braced frames used in regions with high seismic hazard are expected to sustain large inelastic deformations through brace buckling in compression and yielding in tension. These actions concentrate damage to the midspan of the brace and gusset plate connections, and fracture typically precipitates at the brace midspan. The longitudinally segmented brace scheme, therefore, focuses on repair of the brace midspan while retaining other regions of the brace, the connections, and the framing members. The major research objectives include: (1) development of segmented brace interface connections that facilitate replacement and improve seismic performance through the introduction of additional controlled yielding mechanisms outside the brace hinge; (2) evaluation of seismic behavior of components retained in repair, including residual capacity and performance-based engineering considerations; and (3) generation of practical modeling approaches, performance acceptance criteria, design guides, and other engineering tools contextualized in existing steel building design and evaluation provisions. Large-scale subassemblage testing of frames with segmented braces will be conducted to investigate the new segmented brace design and the effect of damage accumulation in other frame components. The inelastic response of a broader range of segmented brace connection configurations and seismic load histories will be studied using experimentally validated continuum finite-element analysis to inform design and modeling guidelines for segmented braces.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该工程研究启动（ERI）奖将使用配置用于快速地球后修复的分段括号为钢制支撑框架开发一种新的地震设计方法。在美国容易受到地震危害的地区建造的建筑物旨在在大地震期间保持安全，但是结构性成分（例如对角线牙套）旨在在消散地震能量时造成损害。这种建筑物的破坏可能是严重的，并且在受震影响的社区中占据了广泛的影响，从而抑制了地震后占用，功能和修复的速度或可能性。钢制支撑框架在各种用途的现有建筑基础设施中很普遍，包括医院，学校，办公室和工业设施，这些设施对于地球后庇护所和人们的照顾，商品分配和经济生产力至关重要。分段的支撑方案将减轻地震损伤对这些通用系统的影响，并通过实现相对较快的，低成本的替换，从而提高地震弹性，以使大多数其他系统组件可以安全地保留。实验测试将研究应用于新建筑和维修方案的分段括号的地震行为。随附的计算研究将扩大这些发现，以评估适合工程实践的设计程序和建模建议的其他设计参数。研究活动将被纳入结构钢设计的实验室体验课程模块中，并通过本科研究机会和外展计划参与工程中代表性不足的团体。 该奖项将促进国家科学基金会在国家地震危害计划（NEHRP）中的作用。 项目数据将在自然危害工程研究基础设施（NHERI）数据仓库（https://www.designsignsafe-ci.org）中进行存档并公开提供。高地震危险区域中使用的较高的支撑框架预计将通过压缩和张力屈服来维持较大的非弹性变形。这些动作将损坏集中在支撑板和毛刺板连接的中跨处，而断裂通常会在支撑中跨处沉淀。因此，纵向分割的支架方案的重点是维修支架中跨，同时保留了支架，连接和框架成员的其他区域。主要的研究目标包括：（1）开发分段的支撑界面连接，通过引入支撑铰链外的其他受控屈服机制来促进并改善地震性能； （2）评估保留在维修中的组件的地震行为，包括剩余能力和基于绩效的工程注意事项； （3）在现有钢结构设计和评估规定中对实用建模方法，绩效接受标准，设计指南以及其他工程工具的生成。将进行带有分段括号的框架的大规模亚汇编测试，以研究新的分段支架设计以及其他框架组件中损伤积累的影响。将使用经过实验验证的连续元素有限元元素分析来研究更广泛的分段支架连接配置和地震负载历史的无弹性响应，以为分段括号的设计和建模指南提供信息。该奖项反映了NSF的立法任务，并认为通过基金会的智力综述和广泛的评估，值得通过评估来进行评估。