Relations between static-structural aspects, construction phases and building materials of San Saturnino Basilica (Cagliari, Italy)

The construction site was used several times: in a first phase, in the republican era of Roman domination it hosted, probably, a temple whose height could reach 25 meters; in a second phase, during the Roman Empire, it was used as a burial area. Then around IV-V century AD a first Christian Basilica made of a naved building with an apse was built there, at the center of a large monastery. Subsequently in a third phase in VI century AD a Byzantine Martyrium, with a Greek cross-shaped plan, was built: the central part of it, supporting a dome is still standing. Finally after 1089 the church was given to Marsilian monks who deeply renovated it and changed its shape converting the plan to a Latin cross. A macroscopic material analysis shows the presence of various rocks, whose use appears to be inhomogeneous during all construction phases. Sedimentary rocks (limestones, sandstones, calcarenites etc belonging to local geological formations) are generally used for masonry structures. Marbles, mostly coming from abroad and previously used in Roman buildings have been adopted for architectural elements (columns, capitals, and so on). At a lower extent there are masonry blocks in Oligo-Miocenic volcanic rocks and seldom stone materials which are not originally from Sardinia. Both mineralogical and petrographic tests (e.g. XRF, XRD) and the most important physical properties (porosity, density, water absorption coefficients, compressive, flexural and tensile strength, etc) show that many of the more representative samples of rock materials (like limestonss, calcarenits) are often highly decayed, with a corresponding reduction of their mechanical strength. A structural analysis is particularly useful for helping in clarifying the historical evolution of the building, checking reconstruction hypotheses and assessing the true residual strength of the more important parts. An example, a FEM analysis of the Byzantine domed part is presented here

Contact interactions in complex fibrous metamaterials: a proposal for elastic energy and Rayleigh dissipation potential

In this work, an extension of the strain energy for fibrous metamaterials composed of two families of parallel fibers lying on parallel planes and joined by connective elements is proposed. The suggested extension concerns the possibility that the constituent fibers come into contact and eventually scroll one with respect to the other with consequent dissipation due to friction. The fibers interact with each other in at least three different ways: indirectly, through microstructural connections that could allow a relative sliding between the two families of fibers; directly, as the fibers of a family can touch each other and can scroll introducing dissipation. From a mathematical point of view, these effects are modeled first by introducing two placement fields for the two fiber families and adding a coupling term to the strain energy and secondly by adding two other terms that take into account the interdistance between the parallel fibers and the Rayleigh dissipation potential (to account for friction)

On nonlinear dilatational strain gradient elasticity

We call nonlinear dilatational strain gradient elasticity the theory in which the specific class of dilatational second gradient continua is considered: those whose deformation energy depends, in an objective way, on the gradient of placement and on the gradient of the determinant of the gradient of placement. It is an interesting particular case of complete Toupin–Mindlin nonlinear strain gradient elasticity: indeed, in it, the only second gradient effects are due to the inhomogeneous dilatation state of the considered deformable body. The dilatational second gradient continua are strictly related to other generalized models with scalar (one-dimensional) microstructure as those considered in poroelasticity. They could be also regarded to be the result of a kind of “solidification” of the strain gradient fluids known as Korteweg or Cahn–Hilliard fluids. Using the variational approach we derive, for dilatational second gradient continua the Euler–Lagrange equilibrium conditions in both Lagrangian and Eulerian descriptions. In particular, we show that the considered continua can support contact forces concentrated on edges but also on surface curves in the faces of piecewise orientable contact surfaces. The conditions characterizing the possible externally applicable double forces and curve forces are found and examined in detail. As a result of linearization the case of small deformations is also presented. The peculiarities of the model is illustrated through axial deformations of a thick-walled elastic tube and the propagation of dilatational waves

THE GEO-REFERENCED XIX CENTURY CARTOGRAPHY: AN ANALYSIS TOOL AND A PROJECT REFERENCE FOR THE PRESERVATION AND MANAGEMENT OF BUILT AND LANDSCAPE HERITAGE

Abstract. Considering built and landscape heritage, the paper demonstrates how it is necessary to conserve the historic stratification and to define new compatible plans and uses, identifying the ways to mitigate alteration impacts, requalify degraded areas, enhance natural, historic and cultural values, improve documentary and educational options, and manage new tasks and opportunities. Particularly, the historic complexity of built and landscape heritage, and the level of permanence can be recognized and evaluated by comparing multi-temporal historic and current maps, and surveying the present situation in order to define preservation strategies.Innovative tools (open source map registry, open source GIS data management) support the critical analysis of the maps, the representation of historic stratification, the evaluation of conservation levels, and the definition of heritage reuse and management. Moreover, innovative applications based on advanced Virtual Hub, when used to publish historical maps as Open Data (GEOPAN ATL@S APP), allow a larger public of non-expert users (tourists, citizens, bikers, students, etc.) to access the extraordinary richness of the historical map contents, and navigate across urban landscapes. Such APPs are thus becoming instruments of awareness with a strong pro-active capacity to stimulate new design plans encompassing local cultural identity and rediscovering traces of the past.</p

ArchNURBS: NURBS-Based Tool for the Structural Safety Assessment of Masonry Arches in MATLAB

A new approach toward a fully computer-aided design (CAD) integrated structural analysis of arched masonry structures is proposed and a new MATLAB-based computational tool, named ArchNURBS, is developed. It is addressed to professionals dealing with the restoration or structural rehabilitation of historical constructions, who need to assess the safety of masonry arches under assigned load distributions. By using it, they can easily produce estimates of the carrying capacity of curved masonry members, and specifically arches of arbitrary shape. A CAD environment, which is very popular among professionals, can be employed to provide a nonuniform rational B-splines (NURBS) representation of arch geometry. On the basis of this representation, it is possible to perform both an elastic isogeometric analysis and a limit analysis of the structure up to the collapse load. Moreover, the developed tool is devised for handling the presence of fiber-reinforced polymers reinforcement strips at the extrados and/or intrados. This allows for the design of properly dimensioned reinforcement and its verification according to current building codes. The entire procedure relies upon a sound theoretical background. ArchNURBS is going to be freely distributed as an open-source project (http://sourceforge.net/projects/archnurbs/)

A GEO-REFERENCED DATABASE TO MANAGE THE LANDSCAPE AREAS UNDER PRESERVATION IN LOMBARDY REGION

Abstract. One of the main goals of the Lombardy Region Landscape Plan (Piano Paesaggistico Regionale – PPR) review was to set up a detailed investigation of landscape binding actions that are issued according to article 136 of the Code of Cultural Heritage and Landscape (D.Lgs. 42/2004).To achieve this goal, a survey was launched and a geo-referenced database was constructed, considering all the data included in the 888 landscape binding actions currently in force in Lombardy.The geo-referenced database takes into account also other architectural preservation measures and natural landscape protections, because a large quantity areas in Lombardy are safeguarded as Regional Parks and Natural Monuments, ecological corridors, geosites and various zones with natural significance are issued as ZPS and SIC by UE.Databases from other agencies and institutions were collected, examined and updated, to provide a complete tool, usable by public administrations and professionals.Such database can also be integrated by multi-temporal geoinformation availability of applications implemented to manage and share georeferenced historical maps (i.e. GEOPAN ATL@S APP), boosting the utility of these data sets in the daily professional activity.</p

MANAGEMENT PLANS AND WEB-GIS SOFTWARE APPLICATIONS AS ACTIVE AND DYNAMIC TOOLS TO CONSERVE AND VALORIZE HISTORIC PUBLIC GARDENS

Abstract. Historic gardens are artefacts that evolve in a continuous and unavoidable way, and, at the same time, they are heritage and cultural sites that need to be conserved: the recognition of this dual nature motivates us to seek for new approaches to their management issues. Whilst it is necessary to follow site mutations and valorize its features while dynamically changes the appearance of the garden and the needs of the society, at the same time it is fundamental that an appropriate strategic plan sets a target for the garden, a midmid-long term vision, in order to preserve botanic and documentary value and maintain historic and artistic significance. The paper analyzes historical sources, surveys, thematic maps and interpretations to study historic public gardens, considering complexity and vulnerability of the components an d issues involved in historic gardens and consequent multidisciplinary approach. In order to identify conservation and management criteria it underlines analysis and evaluation of the environmental, architectural, land scape and perceptive features of the historic garden and its surroundings, demonstrating the importance to study the site historic stratification and the site context in order to define preservation goals to prevent decay, to mitigate impacts, to set up maintenance programs and management plans. The aim of this essay is also to highlight the role of GIS and WebGIS applications – targeted at public administrations – that integrate the spatial component (topographic map, ortophoto, physical plans, cadastral maps) and databases about botanic inventories and conservation and valorization treatments of historic public of public gardens.</p