An assessment of the movements of the parish church of Saint Mary, Birkirkara

Abstract

This dissertation presents a comprehensive study of the Old Parish Church of Birkirkara, dedicated to St. Mary, with a focus on the analysis of structural movements in relation to the church’s fabric and its foundations. The assessment draws on ground investigation data, three-dimensional LiDAR surveys, and a Finite Element Model. The literature review traces the historical evolution of the Church, with attention to reconstruction and restoration efforts assessed in line with observed structural defects. The adopted research methodology integrates multiple approaches, including a detailed 3D laser scanning survey of the interior and exterior, and the interpretation of movement monitoring data collected between 2015 and 2025. These findings are evaluated alongside on-site observations and the Finite Element Model developed by Masciotta Studio (2022). The study reveals that the church exhibits measurable seasonal and long-term structural movements, with significant cracking concentrated in the main nave, transept crossing, and side chapels. Crack gauge monitoring highlighted temperature-driven variations, with peaks in winter and troughs in summer, while inclinometers recorded measurable rotations in critical structural planes. Geotechnical investigation confirmed variable subsoil conditions that influence settlement and contribute to differential displacements. Comparison with the FEM analysis showed discrepancies, particularly in predicting compressive stresses in the barrel vault at the crossing, highlighting the need for model refinement. By synthesising these diverse data sources with prior studies, the research provides a holistic understanding of the church’s structural behaviour. The results emphasise that the observed movements are the combined outcome of environmental, structural, and geotechnical factors. This knowledge contributes to developing more reliable predictive models and informing future stabilisation interventions.