1,721,052 research outputs found
The model of Heyman and the statical and kinematical problems for masonry structures
No full textThe study of masonry mechanics requires a methodological approach radically different from the ones used for ductile structures. The main criteria adopted for the design of the latter, such as strength, stiffness and elastic stability, have a minor role in masonry structures. Even if this peculiar behaviour is rather evident, this point of view is far from manifesting itself among structural architects and engineers. Indeed, the theory of Heyman, giving a modern turn to the old approach to masonry design by means of clear cut simplifications, is in sharp contrast with the sophisticated constitutive theories made possible by finite element methods and the use of super-computers. In these notes, the implementation of Heyman's model for masonry on a computer is introduced. In particular, we describe a simple method based on energy minimization allowing the evaluation of the combined effect of loads and settlements on real masonry structures
Masonry behaviour and modelling
No full textIn this Chapter we present the basic experimental facts on masonry materials and introduce simple and refined models for masonry. The simple models are essentially macroscopic and based on the assumption that the material is incapable of sustaining tensile loads (No-Tension assumption). The refined models account for the microscopic structure of masonry, modeling the interaction between the blocks and the interfaces
Practical applications of unilateral models to Masonry Equilibrium
No full textThis Chapter is devoted to the application of unilateral models to the stress analysis of masonry structures. Some 2d applications of what we call the simplified models for masonry, are discussed and studied. Though the essentially unilateral behaviour of masonry is largely recognized, some prejudices still persist on the possibility of making the No-Tension (NT) assumption a practical model for designing engineers. The results here presented demonstrate that the unilateral model for masonry can be a useful tool for modeling real masonry structures. In the exposition the critical points are emphasized and strategies to handle them are suggested, both for the most primitive model (namely the Rigid NT material), and for the more accurate Normal Elastic NT and Masonry-Like (ML)materials. The first tool here introduced for applying the No-Tension model to structures is the systematic use of singular stress and strain fields. Next a number of closed form solutions for NENT and ML materials is discussed. Finally a numerical approach based on descent is proposed for handling the zero-energy modes typical of unilateral materials. Some numerical solutions and comparisons with analytical solutions and test results are also presented. This Chapter is dedicated to Giovanni Castellano who inspired most of my work on masonry since my early step
Stability analysis and seismic vulnerability of large masonry domes
No full textThis research specifically deals with the issue of the stability of the dome of St. Francesco di Paola (1816) in Naples. It represents the largest dome of its type and is the most significant example of Neapolitan Neoclassical architecture and as such generates great interest due to its solid and impressive structure. Structural analysis of the dome is performed using Heyman's Theory of Limit Analysis for masonry structures and, in particular utilises traditional methods that make use of a static approach based on graphic statics and on the interpretation of thrust lines of stone arches. As is well known, displacements are common in historic masonry structures due, for example, to consolidation of materials, imperfections in construction or differential settlements in foundations. The structural method applied in this work does not aim to define the cause of these displacements but rather seeks to understand their influence on the stability of the construction. With this perspective, in addition to the static analysis, a kinematic analysis approach has been necessary to enable an understanding of the range of possible movements of the masonry structure. Thus, the research of the dome’s minimum thrust has been checked both by static and kinematic approaches in order to assess the safety of the construction. Furthermore, the effects of earthquakes have been explored. By introducing horizontal forces proportional to the weight, it has been possible to assess dome stability under horizontal actions and to determine the limit value of the dome inclination for which the masonry is still entirely compressed. © 2019, International Masonry Society. All rights reserved
On the statics of large domes: A static and kinematic approach for San Francesco di Paola in Naples
No full textThe aim of this paper is to establish a general methodology of approach to assess the safety of the architectural heritage. Starting to a "case study", the problem of the behavior analysis of masonry buildings has been developed on the basis of some simple hypotheses about the material and on the basis of theoretical concepts. The Elastic Theory, used to check modern structures, is not suitable for masonry, material much more heterogeneous and complex. As demonstrated by the ancient builders, the most appropriate theory to study historical constructions is the Limit Analysis [1]: a better understanding of the mechanics for these structures is needed, since it is not the stress the most important parameter for masonry, but it is the stability [2]. The case approached deals with the dome of the Basilica of San Francesco di Paola in Naples, designed and built by the Swiss architect Pietro Bianchi in the nineteenth century, for the royal will of Ferdinand IV of Bourbon [3,4]. In order to assess this structure, the limit analysis approaches are here compared and, on the basis of classical limit analysis, local mechanisms are considered. A static (safe theorem) and a kinematic approach are applied to the structure by means of equilibrium limit conditions and kinematically admissible collapse mechanisms. © 2018 The International Masonry Society (IMS)
The neoclassical dome of san francesco di Paola in Naples. A study on form and stability. (Aimeta 2017)
No full textThe Basilica of San Francesco di Paola, located at the west side of Piazza del Plebiscito, historic center of Naples, was built as a completion of the square in front of the Royal Palace by the will of King Ferdinand IV (1816), designed by the Swiss architect Pietro Bianchi. The "The Bourbon Temple" is mainly characterized by its imposing coverage with hemispherical dome, which protrudes from the complex. It directly refers to the Pantheon for its geometric relations and proportions, its formal and compositive aspects, although it is not completely hemispherical and its interior does not enjoy the spatiality of its model. Furthermore in origin the dome ended with a central oculus in which, even today, the structural forces converge and balance. Subsequently, a lantern was placed on the oculus, which is a conical element completely in glass that allows the passage of light. The aim of this work is the study of the stability of the dome that, firstly, allows to specify the overall safety of the structure in its current state, especially with regard to statics. Secondly, to assess the degree of seismic safety of the structure, identifying the potential conditions of vulnerability in case of earthquake. The static analysis has been performed, by using the graphical method, according with the principles of the limit analysis applied by Heyman to the masonry structures. The methodological innovation consists in the use of the traditional methods of graphical calculation of masonry structures, interconnected with the new antiseismic norms in the territory. The operational aspect of the work is contained in the interdisciplinarity of scientific fields, with the aim of obtaining a complete knowledge of the monument in its current condition without using an elastic analysis, which would not be suitable for the study of historical building
A limit analysis approach for masonry domes: the basilica of San Francesco di Paola in Naples
No full textThe object of the present study is the basilica of San Francesco di Paola, an historical structure that well lends itself to use the graphic method of statics to analyse its stability for a two-fold reason: on the one hand, it is an interesting structure being dominated by a dome of considerable size with a solid appearance, and on the other, it is an entirely masonry structure for which no consolidation interventions with different materials have been necessary so far. This paper applies limit analysis based on the geometric equilibrium of the dome starting from detailed surveys of the church, from the knowledge of its history construction to the comprehension of the entire building. The study carried out enriches previous researches developed around the same case study, and the new contribution is integrated by the analysis of stability of the buttress system that completes the work on the vertical loads, providing a more detailed assessment of the safety level of the structure
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