Exploring the impact of high-frequency/low-energy earthquakes on old stone masonry structures

该项目将启动麦吉尔大学（加拿大蒙特利尔）和米尼奥大学（葡萄牙吉马良斯）之间的新的战略性国际合作，旨在调查高频/低能量地震对旧石砌结构的平面外（OOP）响应的未探索影响，主要在加拿大，葡萄牙和国外的许多人口稠密的城市中心。地震波的高频分量通常被忽略作为现代建筑物的结构损坏的来源，因为太高而不能与其固有频率共振并且具有小的能量含量。然而，在旧石砌体建筑中，高频振动可导致砌体单元的不可逆错位、分层和碎石芯液化，从而导致突然倒塌。虽然这些破坏模式经常在地震后的调查中被发现，但人们对这一现象仍然知之甚少，这损害了公共安全。该合作项目的创新目标是量化高频/低能量OOP地震波下旧石砌体结构的破坏程度、强度和位移能力。为了在麦吉尔大学和UMinho大学开设这条新的调查路线，采用了多尺度方法，该方法结合了加拿大地区典型的碎石砌体子结构的缩小规模实验振动台测试和先进的离散元随机模拟（但也存在于葡萄牙建筑传统中）。预期成果，包括确定经常性OOP倒塌机制和代表性组件的关键抗震性能指标，将构成一个独特的基线数据，为后续研究提供信息-这对制定临时减灾战略和调查其他变量的影响至关重要。这项探索性研究与UMinho合作-世界领先的砖石研究机构-将为参与的学生提供丰富的培训经验，同时推进加拿大在一个研究不足但非常相关的领域的地位，符合国家优先事项（加拿大净零2050）和承诺（仙台减少灾害风险框架）保护建筑环境。

This project will initiate a new strategic international collaboration between McGill University (Montreal, Canada) and the University of Minho (Guimaraes, Portugal) that aims to investigate the unexplored impact of high-frequency/low-energy earthquakes on the out-of-plane (OOP) response of old stone masonry structures, predominant in many populous urban centers of Canada, Portugal and abroad. The high-frequency components of seismic waves are usually disregarded as a source of structural damage for modern constructions, being too high to resonate with their natural frequencies and having small energy content. However, in old stone masonry buildings, high-frequency vibrations can result in irreversible dislocation of masonry units, delamination and rubble core liquefaction, leading to sudden collapses. Although these failure modes are often detected in post-earthquake surveys, this phenomenon remains poorly understood, undermining public safety. The innovative objective of this collaborative project is to quantify the damage extent, strength and displacement capacities of old stone masonry structures under high-frequency/low-energy OOP seismic waves. To open this new line of inquiry at both McGill and UMinho, a multiscale approach is adopted that combines reduced-scale experimental shake-table tests and advanced Discrete Element stochastic simulations of rubble stone masonry sub-structures typical of Canadian regions (but also present in Portuguese construction tradition). Expected outcomes, including the identification of recurrent OOP collapse mechanisms and key seismic performance indexes of representative assemblies, will constitute a unique baseline data on which to inform subsequent research - crucial for devising ad-hoc mitigation strategies and investigating the effect of additional variables. This exploratory study in partnership with UMinho - a world-leading institution in masonry research - will provide participating students enriched training experiences while advancing Canada's position in a deeply under-researched yet extremely relevant area, in line with national priorities (Canada Net-Zero 2050) and commitments (Sendai Framework for Disaster Risk Reduction) for preserving the built environment.