Handbook of Research on Seismic Assessment and Rehabilitation of Historic Structures
The chapter reports on the in-situ experimental campaign and the numerical modelling that were pe... more The chapter reports on the in-situ experimental campaign and the numerical modelling that were performed to assess the static and dynamic behaviour of the Cupola of the Siena Cathedral in Italy: an irregular polygonal masonry structure built in the 13th century and composed of two domes. The research was motivated by the failure of some of the stone-trusses which connect the two masonry domes and consists of: a) single and double flat-jack tests in the internal dome, b) dynamic vibration tests on the Cupola under environmental (wind) and artificial (vibrodyne) loads and c) dynamic vibration tests on the double colonnade located below the Cupola (hammer impact tests). Results of tests were employed to identify a numerical model of the Cupola, which allowed to simulate its structural behaviour and to account for the failure of the stone-trusses between the two domes. The numerical model was later extended to the whole Cathedral. Through the discussion of an emblematic case study, the ...
The key topic discussed in this paper concerns the geometrical issue of the structural optimizati... more The key topic discussed in this paper concerns the geometrical issue of the structural optimization, where two approaches are used to obtain the best bending-free state of stress for a triangular shell. In the first approach, starting from an assigned initial shape, the unknown optimal geometry is obtained manipulating the form by means of an ad hoc parametric function, e.g. polynomial, exponential, etc., whose parameters are assumed as design variables. This approach allows to reduce drastically the number of the variables, on the other hand, the generality of the generated shapes depends strongly on the choice of the parametric function. The second is a much more general tool for the surface representation, namely, a CAGD (Computer Aided Geometric Design) technique has been implemented and the initial shape of the selected example has been approximated through a triangular Bézier surface made up of triangular patches. The approximate surface is controlled by the Cartesian coordina...
ABSTRACT La memoria riporta i risultati ottenuti su alcuni casi studio sviluppati nell’ambito del... more ABSTRACT La memoria riporta i risultati ottenuti su alcuni casi studio sviluppati nell’ambito delle attività preliminari del progetto di ricerca “RiSEM - Rischio Sismico negli Edifici Monumentali”. Il progetto nasce con lo scopo di mettere a punto tecniche di indagine, di analisi e di diagnosi che consentano, in maniera speditiva e con costi relativamente contenuti, di stabilire il rischio sismico di beni monumentali. In ambito specificatamente strutturale, la prima parte della ricerca è stata finalizzata al confronto tra diverse tecniche di modellazione numerica per la definizione del comportamento in campo non lineare di una serie di elementi in muratura sottoposti ad azioni orizzontali. I casi sono stati individuati seguendo il duplice obiettivo di: 1) definire in maniera corretta i parametri di crisi degli elementi strutturali, in modo da poter procedere alla messa a punto di modelli numerici semplificati; 2) fornire una stima delle incertezze di tipo epistemico, ossia collegate alle diverse modellazioni, al fine di poter giungere ad una definizione del rischio sismico in termini probabilistici. Dopo una breve descrizione del progetto, i casi studio analizzati sono riportati e ne vengono illustrati alcuni risultati.
The key topic discussed in this paper concerns the geometrical issue of the structural optimizati... more The key topic discussed in this paper concerns the geometrical issue of the structural optimization, where two approaches are used to obtain the best bending-free state of stress for a triangular shell. In the first approach, starting from an assigned initial shape, the unknown optimal geometry is obtained manipulating the form by means of an ad hoc parametric function, e.g. polynomial, exponential, etc., whose parameters are assumed as design variables. This approach allows to reduce drastically the number of the variables, on the other hand, the generality of the generated shapes depends strongly on the choice of the parametric function. The second is a much more general tool for the surface representation, namely, a CAGD (Computer Aided Geometric Design) technique has been implemented and the initial shape of the selected example has been approximated through a triangular Bézier surface made up of triangular patches. The approximate surface is controlled by the Cartesian coordina...
This paper discusses the cracking pattern in a historical Italian palace proposing a diagnosis fo... more This paper discusses the cracking pattern in a historical Italian palace proposing a diagnosis for the origin of the actual damage state. The analyzed building, which dates back to the seventeenth century, is a masonry building with a rectangular plan section located in Piancastagnaio (South Tuscany, Italy). The building exhibits a severe and variegated vertical and horizontal cracking pattern mainly affecting the southern and eastern façades. Due to the damage, the palace was evacuated by the Public Authorities during the 1980s and a series of provisional remedies (mainly steel chains) was added. Through the use of the finite element technique, the paper provides an interpretation of the manifested damage. The aim of the diagnosis, supported by the numerical results, is to design an extensive in-situ investigation on the palace. Moreover, the paper aims at evaluating the effectiveness of the actual temporary retrofitting (mainly steel chains) used to freeze the present damage. At the end of the paper the in-situ investigation is presented and discussed.
Handbook of Research on Seismic Assessment and Rehabilitation of Historic Structures
The chapter reports on the in-situ experimental campaign and the numerical modelling that were pe... more The chapter reports on the in-situ experimental campaign and the numerical modelling that were performed to assess the static and dynamic behaviour of the Cupola of the Siena Cathedral in Italy: an irregular polygonal masonry structure built in the 13th century and composed of two domes. The research was motivated by the failure of some of the stone-trusses which connect the two masonry domes and consists of: a) single and double flat-jack tests in the internal dome, b) dynamic vibration tests on the Cupola under environmental (wind) and artificial (vibrodyne) loads and c) dynamic vibration tests on the double colonnade located below the Cupola (hammer impact tests). Results of tests were employed to identify a numerical model of the Cupola, which allowed to simulate its structural behaviour and to account for the failure of the stone-trusses between the two domes. The numerical model was later extended to the whole Cathedral. Through the discussion of an emblematic case study, the ...
The key topic discussed in this paper concerns the geometrical issue of the structural optimizati... more The key topic discussed in this paper concerns the geometrical issue of the structural optimization, where two approaches are used to obtain the best bending-free state of stress for a triangular shell. In the first approach, starting from an assigned initial shape, the unknown optimal geometry is obtained manipulating the form by means of an ad hoc parametric function, e.g. polynomial, exponential, etc., whose parameters are assumed as design variables. This approach allows to reduce drastically the number of the variables, on the other hand, the generality of the generated shapes depends strongly on the choice of the parametric function. The second is a much more general tool for the surface representation, namely, a CAGD (Computer Aided Geometric Design) technique has been implemented and the initial shape of the selected example has been approximated through a triangular Bézier surface made up of triangular patches. The approximate surface is controlled by the Cartesian coordina...
ABSTRACT La memoria riporta i risultati ottenuti su alcuni casi studio sviluppati nell’ambito del... more ABSTRACT La memoria riporta i risultati ottenuti su alcuni casi studio sviluppati nell’ambito delle attività preliminari del progetto di ricerca “RiSEM - Rischio Sismico negli Edifici Monumentali”. Il progetto nasce con lo scopo di mettere a punto tecniche di indagine, di analisi e di diagnosi che consentano, in maniera speditiva e con costi relativamente contenuti, di stabilire il rischio sismico di beni monumentali. In ambito specificatamente strutturale, la prima parte della ricerca è stata finalizzata al confronto tra diverse tecniche di modellazione numerica per la definizione del comportamento in campo non lineare di una serie di elementi in muratura sottoposti ad azioni orizzontali. I casi sono stati individuati seguendo il duplice obiettivo di: 1) definire in maniera corretta i parametri di crisi degli elementi strutturali, in modo da poter procedere alla messa a punto di modelli numerici semplificati; 2) fornire una stima delle incertezze di tipo epistemico, ossia collegate alle diverse modellazioni, al fine di poter giungere ad una definizione del rischio sismico in termini probabilistici. Dopo una breve descrizione del progetto, i casi studio analizzati sono riportati e ne vengono illustrati alcuni risultati.
The key topic discussed in this paper concerns the geometrical issue of the structural optimizati... more The key topic discussed in this paper concerns the geometrical issue of the structural optimization, where two approaches are used to obtain the best bending-free state of stress for a triangular shell. In the first approach, starting from an assigned initial shape, the unknown optimal geometry is obtained manipulating the form by means of an ad hoc parametric function, e.g. polynomial, exponential, etc., whose parameters are assumed as design variables. This approach allows to reduce drastically the number of the variables, on the other hand, the generality of the generated shapes depends strongly on the choice of the parametric function. The second is a much more general tool for the surface representation, namely, a CAGD (Computer Aided Geometric Design) technique has been implemented and the initial shape of the selected example has been approximated through a triangular Bézier surface made up of triangular patches. The approximate surface is controlled by the Cartesian coordina...
This paper discusses the cracking pattern in a historical Italian palace proposing a diagnosis fo... more This paper discusses the cracking pattern in a historical Italian palace proposing a diagnosis for the origin of the actual damage state. The analyzed building, which dates back to the seventeenth century, is a masonry building with a rectangular plan section located in Piancastagnaio (South Tuscany, Italy). The building exhibits a severe and variegated vertical and horizontal cracking pattern mainly affecting the southern and eastern façades. Due to the damage, the palace was evacuated by the Public Authorities during the 1980s and a series of provisional remedies (mainly steel chains) was added. Through the use of the finite element technique, the paper provides an interpretation of the manifested damage. The aim of the diagnosis, supported by the numerical results, is to design an extensive in-situ investigation on the palace. Moreover, the paper aims at evaluating the effectiveness of the actual temporary retrofitting (mainly steel chains) used to freeze the present damage. At the end of the paper the in-situ investigation is presented and discussed.
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Papers by M. Orlando