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The structural assessment of historical buildings is a complex and articulated problem based on different activities. This paper describes the different phases of an integrated approach to obtain an accurate knowledge of the structural damage and seismic performance of two masonry Baroque churches located in Northern Italy and hit by the 2012 Emilia earthquake. The activities involved historical research, laser scanning survey, diagnostic investigation and structural analysis. The historical research, based on the analysis of written documents and historical maps, aimed at understanding previous structural problems and major changes in the structure over the centuries. The geometrical survey of the churches was performed by means of a laser scanner technique in order to very precisely determine the geometry of the two churches. Experimental tests and visual inspections allowed identifying location and extent of cracks, construction techniques, presence of voids and defects in structural masonry walls, as well as some characteristics of masonry. Based on this information, detailed three-dimensional finite element models of the two churches were developed and non-linear dynamic analyses were performed. The numerical simulations led to the determination of damage distribution and the identification of the most vulnerable elements, highlighting the main structural deficiencies of the churches when subjected to different levels of seismic actions. [ABSTRACT FROM AUTHOR]

The architectural heritage was severely damaged by the seismic sequence that occurred in Emilia (Northern Italy) in May 2012. This paper investigates the seismic behavior of three masonry churches that were damaged by the 2012 Emilia earthquake. The analyzed churches are located in the South-East area of the province of Mantua: they are representative of some churches, denoted as 'Matildic churches', belonging to the territorial area between Lombardia, Emilia Romagna and Toscana and built during the Matilde di Canossa domain, between the X and the XI centuries. The study was based on detailed field surveys, in situ tests, visual inspections and existing archives in order to obtain an accurate knowledge of the churches and a proper evaluation of the damage caused by the earthquake. Then, detailed finite element models of the churches were developed and non-linear dynamic analyses with different peak ground accelerations were performed. The numerical simulations provided a deep insight into the seismic behavior of the analyzed churches, identifying the damage patterns and the main collapse mechanisms for different seismic intensity levels. The obtained results appear to be in a good agreement with the damage experienced by the churches during the earthquake. This study can be considered as a first step to assess the seismic vulnerability of the 'Matildic churches', extremely important for their historical and architectural value. [ABSTRACT FROM AUTHOR]

In this paper, a numerical approach for the pushover analysis of masonry towers, having hollow arbitrary sections, is proposed. Masonry is considered a nonlinear softening material in compression and brittle in tension. The tower, modeled in the framework of the Euler-Bernoulli beam theory, is subjected to a predefined load distribution, but the problem is formulated as a displacement controlled analysis in order to follow the post peak descending branch of the structural response. Nonlinear geometric effects and nonlinear constraints (the latter due to surrounding buildings) are also considered. Benchmarking pushover analyses are performed with the commercial code Abaqus in relation to a real case (the Gabbia Tower in Mantua), which proved the accuracy and reliability of the results obtained with the present formulation and the noteworthy reduction of computing time. [ABSTRACT FROM AUTHOR]

In this paper a masonry baroque church by Antonio Galli Bibiena in Villa Pasquali is analyzed using a multidisciplinary approach. The importance of this monument is due to the prestige of its architect and to the peculiar system of masonry perforated vaults, which is an unicum in architectural history. Nevertheless, until now this church has not been studied, but historical data and significant crack patterns have pointed out its high vulnerability. The first step related to the knowledge of the building consists of the historical record of archival documents, which allow for the identification of the vulnerable elements. An accurate geometric survey is carried out with Terrestrial Laser Scanning in order to detect the complex three-dimensional geometry of the structure and crack patterns. Finally, a three-dimensional finite element model of the entire structure is developed and a comparison between the numerical results and the damage survey is performed. [ABSTRACT FROM AUTHOR]

Scaling phenomena in the progressive debonding between fiber reinforced polymer (FRP) strips and concrete substrate are examined on the basis of single lap shear tests, considering different bond lengths and widths. To capture a stable post-peak response of the FRP-concrete joint, the slip between the concrete support and the reinforcement strip, measured at the reinforcement end using a clip gage, was selected as feedback control signal during the tests. This allowed a quasi-static stable fracture propagation in the descending branch until complete load relaxation and debonding. Experimental tests were simulated by means of 2D and 3D finite element analyses adopting two different approaches. At first, a numerical model based on linear elastic materials with all non-linearities concentrated at the interface was assumed. It clearly revealed the inability to recognize all the aspects of the debonding process. Then, a different numerical model, based on a non-linear constitutive model for concrete and perfect adhesion between all the materials, was adopted. [ABSTRACT FROM AUTHOR]

In this paper, debonding phenomena between carbon fiber reinforced polymer (CFRP) strips and masonry support were investigated on the basis of single-lap shear tests, considering different dimensions of the bond length. To capture the post-peak response of the CFRP–masonry joint, the slip between the support and the reinforcement strip was controlled using a clip gauge positioned at the end of the reinforcement. The tests were simulated by means of a finite element model able to capture the post-peak snap-back behavior due to the failure process. The numerical model is based on zero-thickness interface elements and on a proper non-linear cohesive law. The comparison between experimental and numerical results was performed in terms of overall response, measured by both the machine stroke and the clip gauge positioned at the free end of the reinforcement. The cases of effective bond length greater and lesser than the minimum anchorage length, suggested by the CNR Italian recommendation, were considered. [ABSTRACT FROM AUTHOR]

Highlights: [•] This paper deals with a historical building: Palazzo del Capitano in Mantua. [•] Material and geometrical surveys are performed. [•] Three dimensional nonlinear dynamic analyses are performed with special attention to finite element discretization. [•] The seismic vulnerability of the building is analyzed. [•] Proposal for restorations are critically assessed. [Copyright &y& Elsevier]

This paper examines how surveying and monitoring improve our knowledge about ancient buildings, allow the interpretation of their structural response and help in the search for the best solutions for their conservation. The case study of Palazzo del Capitano in Mantua (Italy) is analyzed. In particular, the attention is focused on the use of a Terrestrial Laser Scanner (TLS) for surveying and monitoring too, considering that the building structural control has been performed in combination with other traditional topographic techniques such as geometric leveling and topographic networks for 3D control based on measurements through total stations. The study of TLS monitoring has been tested only in the last decade and it is an innovative method for the detection of displacements of particular surfaces. Till now the research has focused only on the use of TLS monitoring to control large structures and in particular landscape situations; thus its use for a civil construction and historical buildings is a new field of investigation. Despite the fact technological development and new methodologies seem offer new future potential for the analysis of ancient buildings, currently there are still important limits for the application of the investigated surveying and monitoring techniques. [ABSTRACT FROM AUTHOR]

• Very few experiments have investigated the orthotropic shear strength of masonry. • Laboratory tests are presented about three shear collapse mechanisms. • A detailed 3D FEM has been implemented to approximate the non linear responses. In this paper the problem of evaluation of the structural response of 1.20 m × 1.20 m blockwork masonry panels under monotonic shear and diagonal-compression tests is investigated. The digital image correlation technique was used to detect the initiation and propagation of damage. The experimental findings were analyzed and simulated also by means of accurate finite element non-linear analyses. The results revealed the non-isotropic shear response of the masonry panels, which is related to the meso-scale structure. The shear response along the two principal directions, when investigated by a test configuration which recall the Iosipescu method, proved to be quite different, being the shear strength parallel to the bed joints mainly dependent on the mortar properties, while the shear strength perpendicular to the bed joints is affected by the bond pattern. The standard diagonal compression tests, on the other hand, showed an intermediate response, even if the orthotropy of shear response could not be explicitly manifest. [ABSTRACT FROM AUTHOR]