PSI - Issue 79

Aikaterini Marinelli et al. / Procedia Structural Integrity 79 (2026) 182–189

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promote collaboration across academia and industry. While numerical modelling can support the understanding of structural behaviour and contribute to more effective monitoring and intervention strategies, the intricate geometries, construction typologies, and material variability of historic masonry structures - together with their sheer number globally - mean that such detailed approaches are typically applied only to a select group of particularly notable or vulnerable examples. Scotland’s historic environment is an essential part of the country’s cultural background and its economy. Stone has been a foundational building material, historically used for everything from prehistoric structures to Georgian and Victorian buildings. Scotland’s building heritage encompasses diverse structures and reflects the country's rich history and culture, through the use of local stone and construction techniques. Given their cultural and historical value, their functional significance as well as the existing regulatory and ethical obligations for maintaining historic structures’ structural integrity and authenticity, it is of utmost importance to enhance their level of care and tackle growing challenges from environmental actions. The Scottish coastline, known for its challenging geography and severe weather conditions, hosts over 300 historic lighthouses, many of which represent significant examples of 19th-century marine engineering and continue to pose complex conservation challenges today (Murray, 2021). These lighthouses not only serve as vital navigational aids but also hold captivating stories of maritime history. By the nature of their role, they are often situated in some very remote places where they are exposed to the elements. The Northern Lighthouse Board (NLB), the General Lighthouse Authority for Scotland and the Isle of Man, provides a vital safety service to mariners since 1786 and currently operate and maintain 208 such lighthouses (NLB, 2025b). NLB’s vision is to ensure an effective response to the climate emergency and adapting to the impact of climate change is a core element of their routine strategic, tactical and operation considerations. The identification of risk-prone areas and the quantitative assessment of projected impacts under varying climate change scenarios are primary areas of focus, with the objective of developing mitigation strategies to reduce the susceptibility of infrastructure to temperature fluctuations and sea level rise (NLB, 2024b, NLB, 2024a). Within that context, any future refurbishment works to lighthouses will be refined to incorporate more risk-based and data-based work programmes, while improved inspection and assessment regimes will yield the required data to inform future expenditures for major work to restore existing assets to their original capacity (NLB, 2023). The NLB aims to assess their current structural condition and enhance monitoring capabilities, to provide site-specific solutions and identify the wider risk interdependencies to mitigate risks posed by climate change. In support of this objective, the present research investigates the potential for developing and applying numerical modelling approaches to improve the structural assessment of historic lighthouse structures. There has been an increasing amount of research on the structural assessment of historic masonry lighthouses, with a focus on effects from extreme marine environments. In the United Kingdom (UK), pioneering studies conducted under the STORMLAMP project (STORMLAMP, 2020), have combined field-based dynamic testing, environmental monitoring, laboratory studies and advanced numerical modelling to characterise the performance of rock-mounted lighthouses under wave-induced loading. Finite Element Method (FEM) and Discrete Element Method (DEM) approaches have different strengths and limitations in capturing the global and local behaviour of these complex structures (D’Altri et al., 2020) . FEM is typically used for preliminary assessment of the overall dynamic response and modal behaviour (Antonini et al., 2019, Pappas et al., 2019), while DEM provides greater fidelity in representing the discontinuous nature of block masonry and failure mechanisms such as joint opening and block dislocation (Pappas et al., 2021). These studies highlight the importance of integrating detailed geometric data, historical construction records and site-specific loading conditions into the modelling framework. Modal testing of lighthouses such as Eddystone and Wolf Rock has enabled calibration of numerical models against measured frequencies and mode shapes, thereby improving their predictive capability under extreme wave impacts (Brownjohn et al., 2018, Trinh et al., 2016, Dassanayake et al., 2020). Nonetheless, challenges remain in representing material degradation, non-linear dynamic response, and both short-term and long-term environmental effects, including those related to climate change. These methodological advances collectively provide a robust foundation for developing site-specific, performance-based assessment strategies for the conservation and resilience enhancement of historic lighthouse infrastructure. Despite this progress, most existing research has focused on structures located in southern and western UK waters, leaving the distinctive conditions and construction typologies of Scottish lighthouses underrepresented in the current literature.