Effect of Geometrical Imperfections on the Response of Dry-Joint Masonry Arches to Support Settlements

This paper aims to investigate the effects of geometrical imperfections on the response of a scaled dry-joint arch to the vertical displacement of one support. The arch behaviour was analysed in the large displacement regime using both physical and numerical modelling. The experimental tests were performed on 1:10 small-scale models made of bicomponent composite blocks with dry joints. In order to evaluate the geometrical accuracy of the blocks, two different sets of voussoirs were produced. The numerical simulations were carried out using a finite element (FE) micro-modelling approach, where the arch was modelled as an assembly of very stiff voussoirs connected by nonlinear interfaces. Particular attention was paid to the interface stiffness, which was set so as to tune the numerical model with the experimental evidence. Experimental and numerical results were then compared in terms of collapse mechanism, hinge configuration and ultimate displacement capacity. The imperfections of the physical models were found to significantly affect the arch response

Historic masonry churches exposed to slow-moving landslides: A critical damage assessment

This paper deals with the damage assessment of historic masonry churches exposed to slow-moving landslides. A damage survey campaign was carried out on 33 listed churches located in the Liguria region (Italy) in areas affected by slow-moving landslides. For each church, information about zoning, state of activity and direction of landslide phenomena was collected and analyzed. Knowledge of each building’s main geometric and structural features, history and past interventions was gained by means on-site surveys and archival research. A detailed field-survey of crack patterns and deformations was also performed. Based on the critical assessment of the damage observed, preliminary conclusions on the structural response of historic masonry churches to slow-moving landslides were made. Recurrent types of damage and damage mechanisms were also identified

Effect of Slow-Moving Landslides on Churches in the Liguria Region: a Geotechnical Approach

Protecting cultural heritage from water-soil interaction related threats is a current issue and the prediction of the effects induced on buildings by landslides is very challenging. The main difficulties lie in the lack of detailed information about landside movements as well as in the modeling of soil-structure interaction. This paper study the effects of a particular category of slow-moving landslides, namely active rotational and translational slides with movement rates of the order of some mm/year, on buildings of historical and cultural interestsuch as churches. Three case studies located in the Liguria region (Italy) were analyzed by performing FEM and LEM numerical analyses on sections representative of the slope

Seismic assessment of masonry cross vaults through non-linear static analyses

Masonry cross vaults are common structural elements in historical buildings. They are largely diffused in all European countries, including those characterized by higher levels of seismicity. Although they have been constructed for centuries, they represent some of the most vulnerable elements of traditional architecture, especially with reference to horizontal loads. The understanding of their behaviour under seismic loading and the definition of their safety are crucial aspects for the accurate assessment of the global health conditions of historical buildings. In the present work, masonry cross vaults are analysed through the Finite Element Method (FEM) and static non-linear analyses are performed considering the effect of different brick pattern. A simplified micro-modelling approach is adopted for the generation of the FEM models and two different brick arrangements are considered, i.e., radial bricks and diagonal bricks, which are the most widespread in European cross vaults. Static non-linear analyses are performed by monotonically incrementing a lateral acceleration until collapse. Results are analysed in terms of maximum load factor, crack pattern and damage mechanisms. The analysis of the results shows that the masonry apparatus strongly influences the vault seismic response both in terms of stiffness and ductility as well as in terms of global capacity

Seismic behaviour of cross vaults with different brick pattern

Cross masonry vaults are common structural elements in historical buildings. They are largely diffused in all European countries, including those characterized by higher levels of seismicity. Although they have been constructed for centuries, they represent some of the most vulnerable elements of traditional architecture, especially with reference to horizontal loads. The understanding of their structural behaviour under seismic loading is a crucial aspect for the accurate assessment of the safety of historical buildings. In the present work, the seismic response of cross masonry vaults is analysed through the Finite Element Method (FEM) and static non-linear analyses considering the effect of different brick patterns and boundary conditions. A simplified micro-modelling approach is adopted for the generation of the FEM models and two different brick arrangements are considered, i.e., radial bricks and diagonal bricks, which are the most widespread in European cross vaults. Two different boundary conditions are assumed in order to simulate a vault with and without lateral confinement. Static non-linear analyses are performed by monotonically incrementing a lateral acceleration until collapse. Results are analysed in terms of maximum load factor, stiffness, ductility, crack pattern and damage mechanisms. The analysis of the results shows that not only boundary conditions, but also the brick pattern strongly influences the vault seismic response both in terms of stiffness and ductility as well as in terms of global capacity

Effect of slow-moving landslides on a vaulted masonry building: The case of San Carlo Borromeo church in Cassingheno (Genova)

This paper presents the structural analysis of San Carlo Borromeo church, a masonry building located in Cassingheno (Genoa, Italy) in an area affected by a slow-moving landslide. A deep knowledge of the building in terms of geometry, structural configuration, history and construction phases was acquired by means of on-site surveys and archival research. The crack patterns were surveyed in detail and the deformations were studied through a point cloud obtained from a LIDAR survey. The comparison between the landslide direction and the damage observed showed discrepancies and suggested the presence of foundation settlements due to other phenomena. To identify the actual causes of damage, a finite element model (FEM) of the building in its hypothetical undeformed configuration was created. The geometry of such configuration was reconstructed starting from the point cloud obtained from the LIDAR survey and removing geometrical defects such as leaning of walls, deformation of vaults and inclination of tie-rods. To simulate the effects produced by the landslide and the foundation settlements on the building over time, nonlinear analyses were performed by imposing different displacement fields at the foundation plane in multiple steps. The damage predicted numerically was then compared with the one experienced by the building, showing good agreement

A Study of Charged P-wave D Meson Production in Semileptonic B Decays

A Study of Charged P-wave D Meson Production in Semileptonic B Decays. A search for the semileptonic decay of B mesons into final states involving charged D** as well as non resonant D0-pi is performed in a sample of approximately 3 million hadronic Z decays recorded with the ALEPH detector at LEP. Topological vertex criteria are used to separate the B -> D**+ l nu X signal from background as well as to search for the non-resonant component B -> D0 pi l nu X. Preliminary results for the branching fraction into resonant and non-resonant components are presented

Slow-Moving Landslide Damage Assessment of Historic Masonry Churches: Some Case-Studies in Italy

This paper presents a contribution for the damage assessment of historic masonry churches exposed to slow-moving landslides. In particular, the authors identified four global damage mechanisms, which are presented here by means of the critical damage assessment of four case studies located in the Liguria region (Italy) in areas affected by slow-moving landslides. For each church, a correlation between the damage patterns observed on-site and the ground movements induced by landslide phenomena was sought by means of visual inspections and crack interpretation. As a result, each damage mechanism was associated to a different pattern of ground movements produced by slow-moving landslides

Three-Dimensional Limit Analysis of the Vicoforte Elliptical Dome

Limit Analysis provides a conceptually simple and robust method to estimate the safety of structures and has been long applied to the analysis of the ultimate collapse state of two-dimensional masonry structures or structural elements. In revolving symmetric domes, the three-dimensional problem can be reduced to the two-dimensional case under appropriate hypotheses. The Vicoforte dome is the largest elliptical dome in the world, and its complex geometry makes this kind of analysis not straightforward. Starting from some basic assumptions, a method for analyzing the three-dimensional elliptical geometry and understand the behavior at collapse of the drum-dome system using limit analysis is proposed. The three dimensional collapse mechanism is found and the system behavior including the presence of tension rings at different levels is interpreted. The results are compared against a nonlinear finite element model