An Uplift Friction Damper for Seismically Resilient Mass-Timber Buildings

该奖项将研究一种适用于交叉叠层木材(CLT)抗震系统(SFRS)的低损害解决方案，该解决方案使用一种新型的提升摩擦阻尼器(UFD)装置，适用于具有地震弹性的大块木材建筑。UFD设备将采用高层CLT建筑中预期的自然摇摆墙行为，提供稳定的能量耗散，并显示出自定心特性。预计在设计水平的地震后，使用这些设备对建筑物进行的结构修复将是最小的。尽管CLT已经成为一种重振木材工业的建筑材料，但目前还缺乏CLT专用的地震能量耗散装置，可以与基于CLT的SFRS的自然运动学进行整体集成。CLT墙板本身并不提供任何可测量的地震能量耗散。作为加州大学圣地亚哥分校自然灾害工程研究基础设施(NHERI)振动台上进行测试的大型十层CLT建筑样本的有效载荷，该项目将使用安装在CLT建筑样本上的UFD设备进行一系列测试，这是美国国家科学基金会奖1636164“协作研究：高层木结构建筑基于弹性的地震设计方法”的一部分。这些试验将用高保真试验数据与实际边界和地震荷载条件下收集的高保真试验数据连接分析和数值模型。校准后的模型将被纳入概率数字框架，以建立抗震能力强的高层木结构建筑的设计方法，从而产生更多样化和生态可持续的城市景观。该项目将提供当地小学外展活动，将本科生少数群体和代表性不足群体的参与纳入研究活动，并促进研究生水平的课程创新。项目数据将被存档，并在国家科学基金会支持的NHERI数据仓库(https://www.DesignSafe-CI.org).)中公开提供该奖项对美国国家科学基金会在国家减少地震灾害计划(NEHRP)中的作用做出了贡献。该有效载荷项目的研究目标是：1)将基于CLT的SFRS的地震响应预测所需的分析和数值模型连接起来的基本力学UFD模型；2)通过实际边界条件和地震载荷的大型试验验证和校准，表征基本的动态UFD行为；3)将基于摩擦的低损伤减震系统替代方案集成到高层木结构基于弹性的抗震设计方法中。为了实现这些目标，收集的试验数据将提供一个关键途径，以可靠地建立数值和分析模型，将振动台试验结果扩展到广泛的原型建筑。采用增量动力分析方法，通过倒塌风险评估，确定大体积木结构原型建筑体系的抗震性能。这将是为基于CLT的SFRS建立基于规范的抗震性能系数的长期目标的第一步。这一奖项反映了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。

This award will investigate a low-damage solution for cross-laminated timber (CLT) seismic force-resisting systems (SFRSs) using a novel uplift friction damper (UFD) device for seismically resilient mass-timber buildings. The UFD device will embrace the natural rocking wall behavior that is expected in tall CLT buildings, provide stable energy dissipation, and exhibit self-centering characteristics. Structural repair of buildings with these devices is expected to be minimal after a design level earthquake. Although CLT has emerged as a construction material that has revitalized the timber industry, there exists a lack of CLT-specific seismic energy dissipation devices that can integrate holistically with the natural kinematics of CLT-based SFRSs. CLT wall panels themselves do not provide any measurable seismic energy dissipation. As a payload to the large-scale, ten-story CLT building specimen to be tested on the Natural Hazards Engineering Research Infrastructure (NHERI) shake table at the University of California, San Diego, as part of NSF award 1636164, “Collaborative Research: A Resilience-based Seismic Design Methodology for Tall Wood Buildings,” this project will conduct a series of tests with the UFD devices installed on the CLT building specimen. These tests will bridge analytical and numerical models with the high fidelity test data collected with realistic boundary and earthquake loading conditions. The calibrated models will be incorporated in a probabilistic numerical framework to establish a design methodology for seismically resilient tall wood buildings, leading to a more diverse and eco-sustainable urban landscape. This project will provide local elementary school outreach activities, integrate participation of undergraduate minorities and underrepresented groups into the research activities, and foster graduate level curriculum innovations. Project data will be archived and made available publicly in the NSF-supported NHERI Data Depot (https://www.DesignSafe-CI.org). This award contributes to NSF's role in the National Earthquake Hazards Reduction Program (NEHRP). The research objectives of this payload project are to: 1) bridge the fundamental mechanistic UFD models linking analytical and numerical models necessary for seismic response prediction of seismically resilient CLT-based SFRSs, 2) characterize the fundamental dynamic UFD behavior with validation and calibration through large-scale tests with realistic boundary conditions and earthquake loadings, and 3) integrate low-damage, friction-based damping system alternatives within a resilience-based seismic design methodology for tall wood buildings. To achieve these objectives, the test data collected will provide a critical pathway to reliably establish numerical and analytical models that extend the shake table test results to a broad range of archetype buildings. The seismic performance of mass-timber archetype building systems will be established through collapse risk assessment using incremental dynamic analyses. This will provide a first step in the longer term goal of establishing code-based seismic performance factors for CLT-based SFRSs.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.