Seismic Retrofit of Horizontal Lateral Force Resisting Systems in Buildings

建筑物水平抗侧力系统的抗震改造

• 批准号: 2050030
• 负责人: Eric Jacques
• 金额: $ 42.23万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050030&HistoricalAwards=false
• 关键词: Seismic; Retrofit; Horizontal; Lateral; Force

This project aims to advance understanding of the vulnerabilities in the horizontal lateral force resisting system of concrete buildings subject to seismic loads and create new approaches for fiber reinforced polymer retrofit through patterns of targeted strengthening and enhanced ductility. The horizontal lateral force resisting system, consisting of the diaphragm, chords, and collectors, often requires retrofit during renovations, when penetrations are cut in the slab, or in older buildings when deficiencies in the in-plane load path, strength, or ductility are discovered. Externally bonded fiber reinforced polymers are increasingly being used to improve diaphragm performance because they are easier to install and do not increase the building weight as compared with conventional concrete and steel strengthening. However, because of their relatively large size and other factors, little research has been conducted to understand how externally bonded composites can be best used to retrofit deficient horizontal lateral force resisting systems. The new retrofit approaches to be developed in this research are important for their potential to increase infrastructure resilience to natural hazards such as earthquakes, as well as improving infrastructure sustainability through adaptive reuse rather than demolition and reconstruction. This project will provide training for graduate and undergraduate students and will curate a social media microblog to excite and inspire individuals underrepresented in science and engineering. This award will contribute to the National Science Foundation (NSF) role in the National Earthquake Hazards Reduction Program (NEHRP). Data from the project will be archived and made publicly available in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (http://www.designsafe-ci.org). The project objectives are to (1) elucidate efficient patterns of triangulated targeted strengthening that are not constrained to orthogonal building axes, (2) enhance cyclic behavior of axial elements in the floor through new concrete confinement techniques, and (3) establish force transfer between the horizontal and vertical systems that may not occur along orthogonal lines. The new fundamental knowledge will unlock opportunities related to nonorthogonal elements, more efficient force flow patterns, and optimization that will be used to advance new design and analysis approaches for diaphragms. The research plan consists of integrated computational and experimental tasks that include: (1) using topology optimization and strut and tie concepts on a set of archetype buildings to develop targeted strengthening approaches, (2) a large-scale experimental study to investigate behavior of existing and retrofitted floors, (3) validation of computational models that can capture the behavior of complex concrete floor systems with and without composite retrofitting, (4) evaluating retrofit approaches using computational models, and (5) synthesizing generalizable design strategies that can be applied to practical diaphragms. The research impact will be broadened through wide dissemination of the research results to the academic community, practicing engineers, and appropriate building code committees.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.

该项目旨在提高对混凝土建筑物水平抗侧力系统在地震荷载作用下的脆弱性的认识，并通过有针对性的加固和增强延性的模式，为纤维增强聚合物加固创造新的方法。水平横向力抵抗系统由横隔梁、弦杆和集热器组成，在翻修期间，当板中切割穿透部分时，或在旧建筑中，当发现平面内荷载路径、强度或延性存在缺陷时，通常需要进行改造。外部粘结的纤维增强聚合物越来越多地用于改善隔膜性能，因为与传统的混凝土和钢加固相比，它们更容易安装并且不会增加建筑物重量。然而，由于其相对较大的尺寸和其他因素，很少有研究已经进行，以了解如何外部粘结复合材料可以最好地用于改造有缺陷的水平侧向力抵抗系统。在这项研究中开发的新的改造方法很重要，因为它们有可能提高基础设施对地震等自然灾害的抵御能力，并通过适应性再利用而不是拆除和重建来提高基础设施的可持续性。该项目将为研究生和本科生提供培训，并将策划一个社交媒体微博，以激发和激励在科学和工程领域代表性不足的个人。该奖项将有助于国家科学基金会（NSF）在国家地震减灾计划（NEHRP）中的作用。该项目的数据将在NSF支持的自然灾害工程研究基础设施（NHERI）数据库（http：//www.example.com）中存档并公开提供。www.designsafe-ci.org 该项目的目标是（1）阐明不受正交建筑轴线约束的三角形定向加固的有效模式，（2）通过新的混凝土约束技术增强楼板中轴向元件的循环性能，以及（3）建立水平和垂直系统之间的力传递，这种力传递可能不会沿沿着正交线发生。新的基础知识将开启与非正交元件、更有效的力流模式和优化相关的机会，这些机会将用于推进隔膜的新设计和分析方法。该研究计划包括综合计算和实验任务，其中包括：（1）在一组原型建筑物上使用拓扑优化和压杆和拉杆概念来开发有针对性的加固方法，（2）大规模实验研究来调查现有和改造楼层的行为，（3）验证计算模型，该计算模型可以捕获具有和不具有复合材料翻新的复杂混凝土楼板系统的行为，（4）使用计算模型评估翻新方法，（5）综合可应用于实际膜片的可推广设计策略。通过向学术界、执业工程师和适当的建筑规范委员会广泛传播研究成果，将扩大研究影响。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的评估被认为值得支持影响审查标准。