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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]

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]