A large part of the world’s architectural heritage is composed of masonry buildings located in seismic areas, and its vulnerability has been shown by the damage caused by the last earthquakes. Meeting the safety demands of cultural heritage buildings according to the performance-based seismic codes requires a deep knowledge of the mechanical properties of material components. Traditional mortars are among these. However, significant samples of structural mortars cannot be taken from existing masonry walls to perform mechanical tests, but tests can, alternatively, be conducted on samples realized according to traditional instructions for composition. Based on a historical study of mix proportions, this paper presents the results of a mechanical test campaign of traditional mortars. The samples were obtained combining lime and pozzolan according to the proportions derived from ancient treatises. The laboratory tests were performed taking into account three different types of limes, and a discussion involving the results presented in the literature is provided. Besides the contribution to fulfilling the lack of knowledge about the mechanical properties of traditional lime mortars, the test results are good references for on-site preparation of mortars for use in restoration. There is a focus on natural pozzolanic lime mortars, widely used in the Neapolitan area and, in general, in the whole Italian territory.
The assessment of the modulus of elasticity and compressive strength of masonry is a fundamental step in the seismic analysis of existing structures. In this paper, the representativeness of the values provided by flat-jack tests for tuff masonry is investigated through the analysis of a very large and homogeneous number of tests (635 double flat-jack tests). Data relate to existing buildings belonging to different historical and/or construction periods, located throughout the Campania region (Italy) in areas with different peculiarities. Results are compared with the values provided by Italian Building Code, containing ranges of the elastic modulus and compressive strength for different types of masonry. The values of flat-jack tests are then compared with laboratory tests available in the literature. Finally, comparisons with code equations are performed. It is shown that equations correlating the masonry compressive strength with the modulus of elasticity provide values larger than the mean of experimental data, whereas the equations correlating the masonry compressive strength with the strength of components provide lower values, if block and mortar strengths are varied within a probable and wide range.
The current seismic prevention strategy is based on a unitary approach aimed at a risk mitigation, also at territorial level. The Italian guidelines for the assessment and mitigation of seismic risk of cultural heritage provides indications for the seismic analysis of protected cultural heritage, with the aim of specifying a path of knowledge, assessing the level of safety and planning possible improvements. The Italian building heritage is very vast and heterogeneous and was devastated by earthquakes due to its high vulnerability; therefore, the seismic risk mitigation also requires the availability of simple and handy analysis tools. The aim of this paper is the illustration of an easy, although approximate, procedure for the evaluation of the seismic safety index and the optimization of strengthening interventions. The procedure is applied to buildings located in the province of Caserta. The analyses are performed with reference to two types of buildings that are particularly recurrent and representative of the building heritage of this area and placed in areas with different seismic hazard.
Non-structural masonry elements represent a significant part of the masonry cultural heritage due to their historical and artistic value. A significant portion of the total losses in recent earthquakes worldwide has been attributed to damage to non-structural elements, that are often very dangerous for public safety. These elements, i.e. merlons, pinnacles, sundial, gable, often undergo out-of-plane failures also for low values of peak ground acceleration. The assessment of the safety of these elements requires a correct evaluation of the seismic demand, to be performed considering the amplification and filtering effects due to the underneath structure, since they are often placed on the upper storeys of the buildings. To that end, the floor spectra are a powerful tool for assessing the earthquake acceleration and displacement requirements on non-structural elements. This paper focuses specifically on the linear and nonlinear kinematic analysis of freestanding masonry elements, comparing the previous Italian Building Technical Code (2008) with that of in force. The out-of-plane overturning mechanism of the protruding portion of the façade of a small chapel is studied, in order to better identify the main parameters that influence the evaluation of seismic safety of such a type of non-structural elements. The seismic demand in acceleration and displacement is computed by floor spectra both through a simplified approach and by using all modes assumed to be significant in the activation the out-of-plane mechanism of the considered protruding element.
In the initial article, the data in the Appendix A Section, Table A6, were incorrect [...]
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