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(葡萄牙吉马雷)之间的一项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平面外(OOP)反应的未探索影响，这种结构主要分布在加拿大、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认为是现代建筑结构损伤的一个来源，因为它太高，不能与其固有频率共振，而且能量含量很小。然而，在老的石砌建筑中，高频振动会导致砌体单元不可逆转的错位、分层和碎石芯液化，导致突然倒塌。尽管这些故障模式经常在震后调查中被检测到，但这种现象仍然知之甚少，破坏了公共安全。该合作项目的创新目标是量化在高频/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McGill和UMinho开辟这条新的调查路线，采用了多尺度方法，将缩减规模的试验性振动台试验和先进的离散元随机模拟结合在一起，这些试验是加拿大地区典型的碎石砌体子结构(但也存在于葡萄牙的建筑传统)。预期结果，包括确定反复出现的OOP倒塌机制和具有代表性的组件的关键抗震性能指数，将构成一个独特的基线数据，以便为后续研究提供信息--这对于制定临时缓解战略和调查额外变量的影响至关重要。这项与世界领先的砖石研究机构UMinho合作的探索性研究将为参与研究的学生提供丰富的培训经验，同时促进加拿大在一个研究严重不足但极其相关的领域的地位，符合国家优先事项(加拿大净零2050)和保护建筑环境的承诺(仙台减少灾害风险框架)。

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.