Cracks are structural pathologies that affect the structural integrity of historical
buildings. The methodologies commonly used to detect cracks are based on visual inspections
or in intrusive techniques that involve removing external wall layers. The main objective of this
study is to develop and validate a semi-automatic and non-destructive tool that helps the user
to analyze the position and growth of the cracks in masonry constructions based on a
photogrammetry analysis. The developed tool uses image processing to plot a curve of the crack
area, and, in case needed, its evolution over time. The tool was validated in laboratory using
earthen samples that were subjected to uniaxial compression tests. The research also provides
the results of the tool used in a case study of a 16th Century stone masonry church located in
the main square of Cusco; Southern Peru. This case study validates the qualitative metrics of
the present work, and indicates that the tool provided accurate results when compared to the
ground truth, which could be helpful in future research studies in order to automatize crack
monitoring.
Abstract
Cracks are structural pathologies that affect the structural integrity of historical
buildings. The methodologies commonly used to detect cracks are based on visual inspections
or in intrusive techniques that involve removing external wall layers. The main objective of [...]
In some cases, the scope of bonded joint characterisation methods applied in laboratory may not be aligned with the bonded joints used in industry. Experimental results produce uncertainty and cause the bonded joints to be replaced by mechanical joints. Experimental procedures evidence a strong dependence on specimen dimensions, type of adhesive, ageing and crack measurement. They are suitable for bonded joints with thin adhesive layers and rigid behaviour while bonded joints in industrial applications have many different geometries and types of adhesive. Moreover, they must withstand external loads and environmental conditions simultaneously, while cracks may not be visible. The present work summarises the methodologies developed to overcome the limitations of current experimental procedures. An analytical method is developed to evaluate the fracture toughness of bonded joints with any width-to-thickness configurations. It is also demonstrated that external loads accelerate the degradation of bonded joints exposed to environmental conditions. Consequently, a new durability test has been developed for bonded joints that considers sustained loads during environmental exposure. Finally, it is demonstrated that the Acoustic Emissions technique is suitable for crack growth monitoring in bonded joints, providing a reliable alternative to locate the cracks when they are not visible.
Abstract
In some cases, the scope of bonded joint characterisation methods applied in laboratory may not be aligned with the bonded joints used in industry. Experimental results produce uncertainty and cause the bonded joints to be replaced by mechanical joints. Experimental procedures [...]
Characterization of Cracks in Historical Buildings Using Image-Processing Techniques 