ERI: Developing Ductility through Replaceable Concrete Anchorage Connections for Improved Seismic Performance of Mass Timber Structures

该工程研究启动（ERI）奖支持研究开发一种改进的抗震木-混凝土连接，使用可更换的延性锚杆，用于震后快速修复。在美国，大量的木结构建筑在世界建筑史上占有重要的地位。为了满足易受地震灾害影响地区的现代设计理念，大型木结构建筑的设计通过集中破坏、延展性和连接中的地震能量耗散来保持大地震时的安全。然而，这些机制不可避免地会导致建筑物损坏，并影响地震后建筑物的整体占用、功能和可修复性，最终影响社区的恢复能力。改进的木结构-混凝土连接将减轻地震破坏对木结构构件的影响，并通过可靠的延性机制来耗散连接木材构件和混凝土基础的锚杆的能量，并允许在损坏后更换拉伸的锚杆，从而增强地震弹性。构件测试将调查木材-混凝土连接的抗震性能，数值研究将扩展这些发现，以评估额外的设计参数，以开发适合工程实践的设计建议和建模建议。研究活动将纳入结构工程的课堂课程模块，并将通过外展计划吸引工程中代表性不足的群体。项目数据将在自然灾害工程研究基础设施数据库（NHERI）中存档并公开提供（https://www.DesignSafe-ci.org）.The)，在木材-混凝土连接中观察到的主要失效机制包括连接钢板和木材部件的小直径紧固件的塑性变形和钢板本身的塑化，从而导致所附木材部件的损坏。改进的延性锚固连接侧重于锚杆变形的概念，以促进整体结构的鲁棒性，延性和强度的增强，限制板和连接的木材部件的损坏，并加速震后木结构建筑的修复。本课题的研究目标包括：(1)探讨延锚连接的抗震性能及其修复后的剩余承载力；(2)探讨整体结构抗震需求与连接承载力的分析方法。采用延性锚杆和可更换螺纹杆的木混结构连接模型进行模拟地震试验，研究新型连接设计及锚杆拉伸长度对连接整体性能的影响。我们将使用实验验证的有限元分析来研究更广泛连接配置的响应，从而为实践工程师提供设计和建模指南。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Engineering Research Initiation (ERI) award supports research to develop an improved seismic resistant timber-concrete connection using replaceable ductile-anchor rods for rapid post-earthquake repair. Of growing interest in the United States, mass timber buildings hold a relevant place in the history of world architecture and construction. To meet the modern design philosophy in regions vulnerable to seismic hazards, mass timber buildings are designed to remain safe during large earthquakes by focusing damage, ductility, and seismic energy dissipation in the connections. However, these mechanisms inevitably induce building damage and affect the overall building post-earthquake occupancy, functionality, and repairability, ultimately impacting community resiliency. The improved timber-concrete connection will mitigate the impact of seismic damage in timber structural components and enhance seismic resiliency by enabling a reliable ductile mechanism to dissipate energy in the anchor connecting timber components to the concrete footing and allowing replacement of the stretched anchor rod after damage. Component testing will investigate the seismic behavior of timber-concrete connections and a numerical study will expand these findings to evaluate additional design parameters toward the development of design suggestions and modeling recommendations suitable for engineering practice. The research activities will be incorporated into an in-class course module in structural engineering and will engage underrepresented groups in engineering through outreach programs. Project data will be archived and made publicly available in the Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org).The main mechanisms of failure observed in timber-concrete connections include plastic deformations of the small diameter fasteners connecting the steel plates to the timber component and plasticization of the steel plate itself, with consequent damage in the attached timber element. The improved ductile-anchor connection focuses on the concept of anchor deformation to promote overall enhanced structural robustness, ductility, and strength, limiting the damage in the plate and in the connected timber component and accelerating the repair of timber buildings in post-earthquake scenarios. The project research objectives include exploring (1) the seismic behavior of the ductile-anchor connection and its residual capacity after repair, and (2) analytical methods relating the overall structural seismic demand to the connection capacity. Simulated seismic tests of timber-concrete connection prototypes with ductile anchor and replaceable thread rod will be conducted to investigate the new connection design and the effect of anchor stretch length on the overall performance of the connection. The response of a broader range of connection configurations will be studied using experimentally validated finite-element analysis to inform design and modeling guidelines for practicing engineers.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.