VERSATIL TOOLS: DIGITAL SURVEY AND VIRTUAL REALITY FOR DOCUMENTATION, ANALYSIS AND FRUITION OF CULTURAL HERITAGE IN SEISMIC AREAS

Abstract. The paper deals with an interdisciplinary research activity aiming at developing a digital and integrated tool able to collect several data concerning the cultural heritage, and to manage and communicate them to a wide community. The small church of San Menna, located in the hamlet with same name in the municipality of Lucoli not so far from L'Aquila city, was the object of the research. The church has been chosen for its historical significance, its architectural peculiarity and for the valuable artworks that it preserves. Based on a photogrammetric model of the church, also used for the remote analysis of cultural asset (planimetric and evolutionary hypotheses, three-dimensional stratigraphic analysis, etc.) a virtual word usable in Virtual Reality (VR) has been developed. The VR setting allows the accessibility of a digital semantic model with information that can be activated with special interactive hotspots (images, texts and audio), which are able to provide an immersive and all-encompassing experience to the tourist. The potentialities of the same tool in the context of diagnosis and conservation process related to cultural heritage in seismic areas, such as those of the Abruzzi Apennines, have also been investigated through the integration of forms concerning the significant features of the artistic assets surveyed in the construction

Mechanical properties of tuff and calcarenite stone masonry panels under compression

A significant number of historic and monumental buildings located in Mediterranean areas, and in particular in South-central Italy, are characterized by soft stone masonry, i.e. tuff or calcarenite. Many are exposed to seismic risk, so that a reference data base in terms of mechanical properties is of paramount importance in seismic assessment of this type of masonry structures. Over the past decades, relevant experimental research has been carried out on masonry panels that represent traditional arrangements. Investigations on their in-plane response under compression, shear and combined shear-compression loading are available. In the present work, a systematic interpretation of available data is carried out with reference to compressive behaviour of tuff and calcarenite stone masonry. The aim is to widen our knowledge about large single and multiple-leaf panel response. Results can be used to validate the estimation of mechanical properties in view of nonlinear analyses of historic masonry structures

Investigation on compressive behaviour of tuff masonry panels

Existing buildings and cultural heritage in the Mediterranean area are commonly composed by tuff masonry made by squared or roughly squared tuff stones. The Neapolitan yellow tuff, in particular, is a high porous volcanic stone that has been widely used as a building material to forge traditional and monumental architecture in the Campania Region. Recent building codes focus their attention on the quantitative evaluation of the performance of existing structures under different limit states. In this context, it is evident that the availability of experimental data is of paramount importance for the vulnerability assessment and performance upgrading of existing tuff constructions. This paper reviews the experimental research carried out on medium-large yellow tuff masonry panels with single and multiple-leaf cross sections. The main target of the current work is to develop an extensive database on material data and mechanical properties of tuff masonry, in the light of recent test results. Based on the collected data, the reliability of available empirical-based relationships for estimation of strength and elastic stiffness of base materials and masonry was investigated. Moreover, the reference values of compressive strength and Young’s modulus given by the Instructions to the Italian Technical Code, 2009 for soft stone masonry, have been compared against available data, and the main results are presented

Seismic hazard disaggregation in the Molise region, Italy: the case study of Campobasso

Large scale experimentations play a relevant role in the earthquake engineering research, similarly Structural Health Monitoring is able to give information of real structures. A few geotechnical structures are documented, because only data on seismic permanent deformations are available. The present paper deals with seismic hazard of the site of the Student House at University of Molise, where a geotechnical monitoring system has been designed and is currently under implementation. It is aimed at refining the seismic hazard characterization for identifying a set of relevant earthquakes for the theoretical analysis of the structure. Reference earthquakes expressed in terms of magnitude (M), distance (R) and ε, were therefore investigated. Uniform hazard spectra at different structural periods for a 475-year return period were disaggregated. Shapes of both the joint and marginal probability density functions were studied and the first two modes of M, R and ε were extracted and discussed

In-plane behavior of tuff masonry panels strengthened with fibre-reinforced plastic cross layout

The paper is aimed at understanding the in-plane shear-compression behaviour of tuff masonry panels strengthened with FRP cross layout. Based on a previous experimental work carried out by some of the authors, a quantitative analysis of the contributions of FRP and bare masonry to reinforced panel shear capacity has been carried out. Force-displacement relationships of all the tested panels are provided, including the intermediate debonding strains. Finally, a critical comparison between the experimental masonry shear strength and the ones calculated according to analytical models suggested by the Italian code NTC 08 and the CNR-DT 200/2004 guideline is presented.- (undefined

Application of the Higher-Order Hamilton Approach to the Nonlinear Free Vibrations Analysis of Porous FG Nano-Beams in a Hygrothermal Environment Based on a Local/Nonlocal Stress Gradient Model of Elasticity

Nonlinear transverse free vibrations of porous functionally-graded (FG) Bernoulli–Euler nanobeams in hygrothermal environments through the local/nonlocal stress gradient theory of elasticity were studied. By using the Galerkin method, the governing equations were reduced to a nonlinear ordinary differential equation. The closed form analytical solution of the nonlinear natural flexural frequency was then established using the higher-order Hamiltonian approach to nonlinear oscillators. A numerical investigation was developed to analyze the influence of different parameters both on the thermo-elastic material properties and the structural response, such as material gradient index, porosity volume fraction, nonlocal parameter, gradient length parameter, mixture parameter, and the amplitude of the nonlinear oscillator on the nonlinear flexural vibrations of metal–ceramic FG porous Bernoulli–Euler nano-beams

Large-scale seismic vulnerability and risk of masonry churches in seismic-prone areas: Two territorial case studies

In this paper, seismic vulnerability and risk assessment of two samples of churches, located in Teramo and Ischia island (Naples gulf), both affected by the most recent earthquakes that occurred in Italy, are presented. To this aim, we applied a simplified method particularly suitable for seismic evaluations at a territorial scale, providing a global resulting score to be compared among the cases analyzed. The data obtained allowed us to provide vulnerability maps and a seismic risk index for all the considered churches. In addition, the calculated indexes permit a preliminary health state evaluation of the inspected churches, for ranking the priorities and planning additional in-depth evaluations

In-plane behavior of tuff masonry panels strengthened with FRP diagonal layout

The present paper deals with a quantitative analysis of the shear strength behavior of masonry panels strengthened with diagonal layout. The objective of the study is to progress towards understanding the shear strength contributions from masonry and FRP to the lateral resistance of strengthened panels. To this aim, relevant experimental results of monotonic shear-compression tests are analyzed. The local behavior of the reinforcement is investigated in terms of FRP strain profiles (i.e. the transferrable tension force within FRP), and its effects on the global response of the panels assessed. The experimental results show the effectiveness of the anchorage system in restraining the FRP at the anchored edges, avoiding premature failure due to FRP debonding. As a result, the specimens were allowed to develop their full lateral resistance. A truss model approach, combined with a proper masonry strength criterion for masonry is proposed and validated. A comparison between computed and experimental data confirms the validity of the procedure in view of practical applications and code recommendations

Locking-free two-layer Timoshenko beam element with interlayer slip

A new locking-free strain-based finite element formulation for the numerical treatment of linear static analysis of two-layer planar composite beams with interlayer slip is proposed. In this formulation, the modified principle of virtual work is introduced as a basis for the finite element discretization. The linear kinematic equations are included into the principle by the procedure, similar to that of Lagrangian multipliers. A strain field vector remains the only unknown function to be interpolated in the finite element implementation of the principle. In contrast with some of the displacement-based and mixed finite element formulations of the composite beams with interlayer slip, the present formulation is completely locking-free. Hence, there are no shear and slip locking, poor convergence and stress oscillations in these finite elements. The generalization of the composite beam theory with the consideration of the Timoshenko beam theory for the individual component of a composite beam represents a substantial contribution in the field of analysis of non-slender composite beams with an interlayer slip. An extension of the present formulation to the non-linear material problems is straightforward. As only a few finite elements are needed to describe a composite beam with great precision, the new finite element formulations is perfectly suited for practical calculations. (c) 2007 Elsevier B.V. All rights reserved