Analysis, Design and System-Level Performance of Repairable Precast Concrete Buckling-Restrained Braced Frames under Seismic Loads

地震荷载下可修复预制混凝土屈曲约束支撑框架的分析、设计和系统级性能

• 批准号: 2230187
• 负责人: Yahya Kurama
• 金额: $ 136.43万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230187&HistoricalAwards=false
• 关键词: Analysis; Design; System; Level; Performance

The scale of losses from previous earthquakes has demonstrated the need for buildings that can rapidly restore their essential functions after a natural disaster. This concept is called functional recovery. This project will contribute to the nation’s functional recovery objectives by creating and examining a repairable precast concrete buckling-restrained braced (BRB) frame structure with a new type of non-proprietary diagonal brace. The new brace will have low-cost features that permit practical replacement after an earthquake. This project will generate fundamental knowledge on the seismic design and performance of this building system. Data will be generated from numerical analyses, testing of isolated braces and their connections, and culminating tests on the seismic performance and repair of a three-story building utilizing the six-degree-of-freedom Large High-Performance Outdoor Shake Table operated by the University of California, San Diego, as part of the NSF-funded Natural Hazards Engineering Research Infrastructure (NHERI). The project will emphasize diversity and inclusion, will engage undergraduates from underrepresented groups in education and mentoring programs, and will create engineering learning modules for pre-college students. Precast industry partners will provide specimens and technical guidance emphasizing the project’s focus on industry-preferred structural details for practical acceptance. Engagement with the broader engineering community will be achieved through a competition to predict the building response on the shake table. Data generated from this project will be archived and made publicly available in the NHERI Data Depot (https://www.DesignSafe-CI.org). This award will contribute to NSF's role in the National Earthquake Hazards Reduction Program (NEHRP). There is currently no comprehensive U.S.-based research on the seismic performance of precast BRB frame structures. This project will fill this research gap by 1) designing and characterizing the behavior of a novel, replaceable concrete brace, 2) evaluating the design and modeling of multi-story braced frames, and 3) evaluating the seismic behavior of these frames within a building. The new brace will achieve ductile and stable behavior by structurally efficient details incorporating energy-dissipating reinforcing bars crossing gap-joints at the brace ends and spliced with threaded couplers and upsized bars to minimize damage in the beam and column members. This threaded gap-joint connection will permit damaged precast braces to be replaced with cast-in-place concrete braces after an earthquake. Detailed numerical models will be developed and experimentally validated to predict three-dimensional stress gradients and damage conditions that could lead to premature failure of the brace, and to evaluate efficient design-basis models for multi-story braced frames. The modeling and design methods will be validated with the first system-level testing of a precast braced frame building on the six-degree-of-freedom shake table. These culminating tests will demonstrate the performance of the braced frames, their connections, and brace replacement under multi-directional demands.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.

以往地震造成的损失规模表明，需要能够在自然灾害发生后迅速恢复其基本功能的建筑物。这个概念被称为功能恢复。该项目将通过创建和检查可修复的预制混凝土屈曲约束支撑(BRB)框架结构来为国家的功能恢复目标做出贡献，该框架结构具有新型的非专有对角支撑。新的支架将具有低成本的特点，可以在地震后进行实际更换。该项目将产生关于该建筑系统的抗震设计和性能的基本知识。数据将来自数值分析、隔离支撑及其连接的测试，以及对一座三层建筑的抗震性能和修复的最终测试，该测试利用了加州大学圣地亚哥分校运营的六自由度大型高性能室外振动台，作为NSF资助的自然灾害工程研究基础设施(NHERI)的一部分。该项目将强调多样性和包容性，将吸引来自代表性不足群体的本科生参与教育和指导计划，并将为大学预科学生创建工程学习模块。预制行业合作伙伴将提供样品和技术指导，强调项目的重点是行业首选的结构细节，以便实际验收。与更广泛的工程界的接触将通过在振动台上预测建筑反应的竞赛来实现。该项目产生的数据将被存档，并在国家医疗保险研究所数据仓库(https://www.DesignSafe-CI.org).)公开可用这一奖项将有助于NSF在国家减少地震灾害计划(NEHRP)中发挥作用。目前，美国还没有关于预制BRB框架结构抗震性能的全面研究。该项目将通过1)设计和表征一种新型的可更换混凝土支撑的性能，2)评估多层支撑框架的设计和建模，以及3)评估建筑内这些框架的抗震性能，来填补这一研究空白。新的支撑将实现延性和稳定的性能，通过结构高效的细节结合能量耗散钢筋跨越支撑端部的间隙节点，并与螺纹连接件和更大尺寸的钢筋拼接，以最大限度地减少对梁和柱构件的损害。这种螺纹缝隙连接将允许在地震后将损坏的预制支撑更换为现浇混凝土支撑。将建立详细的数值模型并进行实验验证，以预测可能导致支撑过早破坏的三维应力梯度和破坏条件，并评估多层支撑框架的有效设计基础模型。通过六自由度振动台上预制支撑框架的首次系统级试验，验证了建模和设计方法的有效性。这些最终测试将展示支撑框架的性能、它们的连接和多方向需求下的支撑替换。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。