Age matters: model predicts how ancient walls will withstand earthquakes  

Historic buildings, constructed from bricks and mortar long before modern engineering, have been worn by centuries of weather extremes, stress and decay. These aging processes alter a building’s structure in complex ways, making it difficult to predict how it will respond to an earthquake.  

Now, researchers at Khalifa University and Aristotle University of Thessaloniki, Greece, have addressed this challenge by developing a modeling method that doesn’t just look at how a historic building was built – but how it has aged. Their method factors in how the physical properties of masonry change over time to better predict what might happen in an earthquake. Their pilot study could help improve future seismic risk assessments and protect both lives, and buildings of historical and cultural importance. 

“Securing the resilience of our heritage buildings is a huge challenge, particularly in seismically active regions such as Greece,” says Andreas Kappos, the structural engineer at Khalifa, who led the study. “The mechanical and physical properties of older, stone-built buildings shift over time as the stone and mortar deteriorate.”  

The physical properties that determine how modern buildings change over time, such as the corrosion of steel, are well-studied. Scientists’ understanding of how masonry changes over time, however, is limited.  

“There is [always] the hope that heritage buildings will survive in perpetuity. Policymakers therefore need robust evidence and predictions to guide decision making.”

Andreas Kappos, Khalifa University 

“It’s difficult to study the deterioration of stone over decades in an experimental set-up, so this is where computer modeling can help,” says Kappos.  

“There is [always] the hope that heritage buildings will survive in perpetuity, and the resulting maintenance and retrofitting costs often come down to governments. Policymakers, need robust evidence and predictions to guide decision making,” he adds. 

Kappos and his team applied a fragility analysis framework, originally developed by their own research group, specifically to masonry buildings. They incorporated data on how the mechanical properties of masonry, such as its ability to withstand compression, tensile and shear forces, change over time in response to environmental conditions such as heat and moisture. These factors influence how much damage an earthquake would cause.  

The researchers used their approach to generate sets of ‘fragility curves’ for a typical Greek masonry building: a two-story, stone building, built in Athens in the 1830s.  

“A fragility curve describes the likely amount of damage expected given a certain strength of earthquake,” says Kappos. “These curves allow us to predict damage severity under multiple earthquake scenarios. Such outputs can help engineers decide which buildings to retrofit and when.”  

A scaled-up, refined version of their method could help guide building inspections and strategies to limit building damage in earthquake zones around the world, says Kappos. Future models could be expanded to include heritage bridges and other ancient structures. 

Reference

Kafetzi, P.P., Papanikolaou, V.K., & Kappos, A.J. Fragility analysis of heritage masonry buildings accounting for ageing effects. J. Build. Eng. 104, 112267 (2025). Article