A study into the effect of ground movement on the deformation of typical local structures consisting of load-bearing HCB walls and reinforced concrete in-situ slabs

Abstract

The 20th century saw rapid growth in the construction industry, especially in recent years, with traditional homes and vacant plots being replaced by apartment blocks. This urban densification has introduced various challenges, particularly the impact of construction on adjacent buildings. Ground movement, notably settlement, can lead to structural deformation, internal stress, strain, and ultimately cracking, which may compromise stability. Weak regulatory enforcement, limited awareness, and profit-driven practices have resulted in severe damage or even collapse of neighbouring structures during nearby construction and excavation. Public awareness about serviceability issues, such as the development of cracks, has grown, driven not only by safety considerations, but also by insurance requirements covering issues like subsidence. Property owners are increasingly vigilant, often escalating concerns into legal disputes, prompting insurance companies to demand stability assessments before issuing coverage. This dissertation aims to investigate the effects of ground settlement on masonry load-bearing structures using numerical modelling in RFEM 6. The focus is on understanding structural behaviour through analysis of deformations, stresses, and strain concentrations. The local masonry construction model was initially calibrated against a full-scale 2D masonry wall. It was then applied to a smaller-scale 3D room structure to further validate its performance. Finally, the calibrated model was used to simulate the deformations observed at Ta’ Kenuna Tower in Nadur, Gozo, enabling a direct comparison between the model’s predictions and the actual deformations. The study culminates in the modelling of an apartment block, reflecting Malta’s construction trends and contributing to safer design practices. The results clearly demonstrate that numerical modelling is a powerful and effective tool for simulating the deformations and stresses experienced by masonry structures subjected to settlement. In some cases, the damage observed in real-life structures was closely reflected in the model's predicted deformations, highlighting the reliability of this approach. In conclusion, numerical modelling offers a cost-effective and insightful method for analysing the impact of ground settlement on masonry load-bearing structures.