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A hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.
A. Sandoli; G. P. Lignola; B. Calderoni; A. Prota. Fragility curves for Italian URM buildings based on a hybrid method. Bulletin of Earthquake Engineering 2021, 19, 4979 -5013.
AMA StyleA. Sandoli, G. P. Lignola, B. Calderoni, A. Prota. Fragility curves for Italian URM buildings based on a hybrid method. Bulletin of Earthquake Engineering. 2021; 19 (12):4979-5013.
Chicago/Turabian StyleA. Sandoli; G. P. Lignola; B. Calderoni; A. Prota. 2021. "Fragility curves for Italian URM buildings based on a hybrid method." Bulletin of Earthquake Engineering 19, no. 12: 4979-5013.
Seismic capacity assessment of existing buildings is of paramount importance for mitigating the seismic risk in earthquake-prone areas. In Europe, the next version of Eurocode 8 and the current version of the Italian standards suggest the adoption of both linear and nonlinear approaches to perform seismic analyses of existing masonry buildings. This paper discusses with the main issues concerning linear and nonlinear analyses methodologies provided by the Italian standards for existing unreinforced masonry buildings. An historical building located in Southern Italy, representative of the Mediterranean basin buildings, has been chosen as a case study and modelled through the equivalent frame model. According to the Italian standards, the influence of in-plane stiffness of floors and spandrels on the overall seismic capacity of the structure has been considered in the analyses. Beyond the code prescriptions, the effect of different ultimate drifts values assumed for the spandrels on nonlinear behavior of the structure has been analysed. The results of two types of linear analyses (lateral static force method and modal response spectrum analysis) have been compared among them and with those provided by the nonlinear static method. Conclusions show that either behavior and overstrength factors provided by the Italian standards are conservative than those estimated through the nonlinear static analyses. Moreover, it has been remarked that the value of ultimate drift adopted for the spandrel can affect significantly the nonlinear response of the structures, although this topic still represents an open issue.
Antonio Sandoli; Gaetana Pacella; Emilia Angela Cordasco; Bruno Calderoni. PROS and CONS of linear and nonlinear seismic analyses for existing URM structures: Application to a historical building. Structures 2021, 32, 532 -547.
AMA StyleAntonio Sandoli, Gaetana Pacella, Emilia Angela Cordasco, Bruno Calderoni. PROS and CONS of linear and nonlinear seismic analyses for existing URM structures: Application to a historical building. Structures. 2021; 32 ():532-547.
Chicago/Turabian StyleAntonio Sandoli; Gaetana Pacella; Emilia Angela Cordasco; Bruno Calderoni. 2021. "PROS and CONS of linear and nonlinear seismic analyses for existing URM structures: Application to a historical building." Structures 32, no. : 532-547.
A hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions.Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure (IM) to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minim value of PGAs defined for each buildings class.To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber (MCS) macroseismic intensity scale has been used and the corresponding fragility curves developed.Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.
Antonio Sandoli; Gian Piero Lignola; Bruno Calderoni; Andrea Prota. Fragility Curves for Italian Urm Buildings Based on a Hybrid Method. 2021, 1 .
AMA StyleAntonio Sandoli, Gian Piero Lignola, Bruno Calderoni, Andrea Prota. Fragility Curves for Italian Urm Buildings Based on a Hybrid Method. . 2021; ():1.
Chicago/Turabian StyleAntonio Sandoli; Gian Piero Lignola; Bruno Calderoni; Andrea Prota. 2021. "Fragility Curves for Italian Urm Buildings Based on a Hybrid Method." , no. : 1.
Cross-laminated timber (CLT) buildings are recognized as a robust alternative to heavyweight constructions, because beneficial for seismic resistance and environmental sustainability, more than other construction materials. The lightness of material and the satisfactory dissipative response of the mechanical connections provide an excellent seismic response to multi-story CLT buildings, in spite of permanent damage to timber panels in the connection zones. Basically, CLT constructions are highly sustainable structures from extraction of raw material, to manufacturing process, up to usage, disposal and recycling. With respect to other constructions, the potential of CLT buildings is that their environmental sustainability in the phases of disposal and/or recycling can be further enhanced if the seismic damage in structural timber components is reduced or nullified. This paper reports a state-of-the art overview on seismic performance and sustainability aspects of CLT buildings in seismic prone regions. Technological issues and modelling approaches for traditional CLT buildings currently proposed in literature are discussed, focusing the attention on some research advancements and future trends devoted to enhance seismic performance and environmental sustainability of CLT buildings in seismic prone regions.
Antonio Sandoli; Claudio D’Ambra; Carla Ceraldi; Bruno Calderoni; Andrea Prota. Sustainable Cross-Laminated Timber Structures in a Seismic Area: Overview and Future Trends. Applied Sciences 2021, 11, 2078 .
AMA StyleAntonio Sandoli, Claudio D’Ambra, Carla Ceraldi, Bruno Calderoni, Andrea Prota. Sustainable Cross-Laminated Timber Structures in a Seismic Area: Overview and Future Trends. Applied Sciences. 2021; 11 (5):2078.
Chicago/Turabian StyleAntonio Sandoli; Claudio D’Ambra; Carla Ceraldi; Bruno Calderoni; Andrea Prota. 2021. "Sustainable Cross-Laminated Timber Structures in a Seismic Area: Overview and Future Trends." Applied Sciences 11, no. 5: 2078.
In-plane seismic behaviour of Cross-Laminated Timber (CLT) walls is influenced by panel-to-panel and panel-to-foundation mechanical connections, which consist of hold-downs and angle brackets. Due to the platform constructional technology, also the orthogonal to grain timber-to-timber contact is involved in the seismic response of the panels. At date, literature theoretical approaches to evaluating the flexural load-bearing capacity of CLT panels focused the attention on the schematization of hold-downs and angle brackets only, under evaluating the role of timber compressed in perpendicular direction. In this paper the influence of the orthogonal to grain timber properties on the overall seismic behaviour of CLT walls has been investigated, proposing a general theoretical model to schematize the panel-to-panel and panel-to-foundation connections. A parabola-rectangle constitutive behaviour has been defined to describe the orthogonal to grain timber behaviour in the connection zones, while hold-downs and angle brackets are modelled adopting literature models. Five different failure conditions, described by mathematical formulations, able to describe the entire axial force-bending moment interaction domain have been defined. The proposed model has been also employed to schematize the connection zones in multi-storey CLT walls with openings, allowing to investigate the effect of the orthogonal to grain properties on its seismic behaviour. Results of nonlinear analyses demonstrate a significant influence of the orthogonal to grain timber properties on seismic behaviour of the walls, affecting its strength, stiffness, ductility and collapse mechanisms.
A. Sandoli; C. D'Ambra; C. Ceraldi; B. Calderoni; A. Prota. Role of perpendicular to grain compression properties on the seismic behaviour of CLT walls. Journal of Building Engineering 2020, 34, 101889 .
AMA StyleA. Sandoli, C. D'Ambra, C. Ceraldi, B. Calderoni, A. Prota. Role of perpendicular to grain compression properties on the seismic behaviour of CLT walls. Journal of Building Engineering. 2020; 34 ():101889.
Chicago/Turabian StyleA. Sandoli; C. D'Ambra; C. Ceraldi; B. Calderoni; A. Prota. 2020. "Role of perpendicular to grain compression properties on the seismic behaviour of CLT walls." Journal of Building Engineering 34, no. : 101889.
Modeling of masonry buildings subjected to seismic actions still represents an open problem in structural engineering. The equivalent frame model is the most used approach to analyze the seismic behavior of both existing and new masonry constructions but, despite this, several aspects are being researched to improve its effectiveness. Among these, modeling of spandrel panels plays a key role to correctly analyze the in-plane seismic response of unreinforced masonry walls. Actually, horizontal mono-dimensional beam-like elements provided of both strength and displacement capacity are used to schematize the spandrel panels, also according with the most of current national and international codes. In this paper an alternative strut and tie scheme to model the spandrel panels, suitable to be used within the equivalent frame approach, is presented: the compressed masonry material is schematized with an equivalent diagonal no-tension truss, whose length and effective compressed area are obtained with limit equilibrium conditions, while tensile-resistant element is represented by no-compression truss. Such model allows a more realistic representation of the mechanical behavior of spandrels because both amount of axial force within the spandrel and the reduced elastic flexural and shear stiffness due to progressive cracking of material are taken into account. Moreover, the local failures of both compressed masonry and/or tensile-resistant elements are better identified and, consequently, also the failure mechanisms of the whole equivalent frame are better detailed. The proposed schematization has been used to simulate the seismic behavior of some reference case studies of existing masonry walls, strengthened with different steel ties arrangement. These walls have been modelled with a hybrid equivalent frame model which consists of mono-dimensional beam-like element for piers, fully rigid offsets for the nodal panels and a strut and tie scheme for spandrels.
Antonio Sandoli; Christian Musella; Gian Piero Lignola; Bruno Calderoni; Andrea Prota. Spandrel panels in masonry buildings: Effectiveness of the diagonal strut model within the equivalent frame model. Structures 2020, 27, 879 -893.
AMA StyleAntonio Sandoli, Christian Musella, Gian Piero Lignola, Bruno Calderoni, Andrea Prota. Spandrel panels in masonry buildings: Effectiveness of the diagonal strut model within the equivalent frame model. Structures. 2020; 27 ():879-893.
Chicago/Turabian StyleAntonio Sandoli; Christian Musella; Gian Piero Lignola; Bruno Calderoni; Andrea Prota. 2020. "Spandrel panels in masonry buildings: Effectiveness of the diagonal strut model within the equivalent frame model." Structures 27, no. : 879-893.
This paper deals with the experimental monotonic and cyclic behavior of masonry spandrels reinforced with Fiber Reinforced Polymers (FRP). The research is a part of a wider program, started by the authors in the last decade, regarding the analysis of the seismic behavior of masonry spandrels in historical buildings of the Mediterranean area. The paper summarizes the properties of the test units, the test set-up and the results of the experimental monotonic and cyclic behavior conducted on twenty-four scaled down H-shaped spandrels made with homogeneous material (e.g. mortar with low tensile strength). Both unreinforced and FRP-reinforced specimens with three different slenderness ratios – e.g. slender, intermediate and squat – and three different arrangements of FRP laminates have been considered for the tests. The main objective has been to verify the possibility of preventing brittle failure modes, typical of spandrels subjected to in-plane seismic actions (e.g. diagonal cracking), and of increasing their strength by applying specific reinforcement systems, so encouraging more ductile behavior characterized by toe-crushing at the ends of the spandrels itself.
A. Sandoli; G. Pacella; G.P. Lignola; B. Calderoni; A. Prota. FRP-reinforced masonry spandrels: Experimental campaign on reduced-scale specimens. Construction and Building Materials 2020, 261, 119965 .
AMA StyleA. Sandoli, G. Pacella, G.P. Lignola, B. Calderoni, A. Prota. FRP-reinforced masonry spandrels: Experimental campaign on reduced-scale specimens. Construction and Building Materials. 2020; 261 ():119965.
Chicago/Turabian StyleA. Sandoli; G. Pacella; G.P. Lignola; B. Calderoni; A. Prota. 2020. "FRP-reinforced masonry spandrels: Experimental campaign on reduced-scale specimens." Construction and Building Materials 261, no. : 119965.
Antonio Sandoli; Bruno Calderoni. Constitutive stress–strain law for FRP-confined tuff masonry. Materials and Structures 2020, 53, 1 .
AMA StyleAntonio Sandoli, Bruno Calderoni. Constitutive stress–strain law for FRP-confined tuff masonry. Materials and Structures. 2020; 53 (3):1.
Chicago/Turabian StyleAntonio Sandoli; Bruno Calderoni. 2020. "Constitutive stress–strain law for FRP-confined tuff masonry." Materials and Structures 53, no. 3: 1.
This paper deals with the influence of the rolling shear deformation on the flexural behavior of CLT (Cross-Laminated Timber) panels. The morphological configuration of the panels, which consist of orthogonal overlapped layers of boards, led to a particular shear behavior when subjected to out-of-plane loadings: the low value of the shear modulus in orthogonal to grain direction (i.e., rolling shear modulus) gives rise to significant shear deformations in the transverse layers of boards, whose grains direction is perpendicular with respect to the tangential stresses direction. This produces increases of deflections and vibrations under service loads, creating discomfort for the users. Different analytical methods accounting for this phenomenon have been already developed and presented in literature. Comparative analyses among the results provided by some of these methods have been carried out in the present paper and the influence of the rolling shear deformations, with reference to different span-to-depth (L/H) ratios investigated. Moreover, the analytical results have also been compared with those obtained by more accurate 2D finite element models. The results show that, at the service limit states, the influence of the rolling shear can be significant when the aspect ratios became less than L/H = 30, and the phenomenon must be accurately considered in both deflection and stress analysis of CLT floors. Contrariwise, in the case of higher aspect ratios (slender panels), the deflections and stresses can be evaluated neglecting the rolling shear influence, assuming the layers of boards as fully-connected.
Antonio Sandoli; Bruno Calderoni. The Rolling Shear Influence on the Out-of-Plane Behavior of CLT Panels: A Comparative Analysis. Buildings 2020, 10, 42 .
AMA StyleAntonio Sandoli, Bruno Calderoni. The Rolling Shear Influence on the Out-of-Plane Behavior of CLT Panels: A Comparative Analysis. Buildings. 2020; 10 (3):42.
Chicago/Turabian StyleAntonio Sandoli; Bruno Calderoni. 2020. "The Rolling Shear Influence on the Out-of-Plane Behavior of CLT Panels: A Comparative Analysis." Buildings 10, no. 3: 42.