An integrated approach for the numerical modeling of severely damaged historic structures: Application to a masonry bridge

Infrared thermography is the science of measuring the infrared energy emitted by an object, translating it to apparent temperature variance, and displaying the result as an infrared image. Significantly, acquiring thermal images delivers distinctive levels of temperature differences in solar panels that correspond to their health status, which is beneficial for the early detection of defects. The proposed algorithm aims to analyze the thermal solar panel images. The acquired thermal solar panel images were segmented into solar cell sizes to provide more detailed information by region or cell area instead of the entire solar panel. This paper uses both the image histogram information and its corresponding cumulative distribution function (CDF), useful for image analysis. The acquired thermal solar panel images are enhanced using grayscale, histogram equalization, and adaptive histogram equalization to represent a domain that is easier to analyze. The experimental results reveal that the extraction results of thermal images provide better histogram and CDF features. Furthermore, the proposed scheme includes the convolutional neural network (CNN) for classifying the enhanced images, which shows that a 97% accuracy of classification was achieved. The proposed scheme could promote different thermal image applications—for example, non-physical visual recognition and fault detection analysis.

Importance of Image Enhancement and CDF for Fault Assessment of Photovoltaic Module Using IR Thermal Image

This paper focuses on the Murena Palace in Perugia, part of an architectural complex designed by Luigi Vanvitelli and completed by Carlo Murena in the 18th century. In the context of the seismic vulnerability assessment of this masonry building, the safety of a construction modulus, which gathers several peculiar features identified within the edifice, is analyzed by means of an integrated architectural-structural approach. This construction modulus, that will be called Vanvitelli’s Modulus, is characterized by an intrinsic structural asymmetry with clusters of rooms with masonry vaults, combining different heights, where load bearing walls are standing on top of the vaults. Given these peculiarities, this construction modulus has to be analyzed as a sub-structure with regards to the seismic vulnerability. To this purpose, experimental tests, in particular videoendoscopies and structural monitoring, were conducted to identify geometrical features of walls and vaults, mechanical characteristic of materials and the actual damage condition. From an accurate survey, an innovative parametric approach has been proposed to build the geometrical model of the construction modulus. This has been used, by FEM (finite element method), to perform a structural analysis whose results have been checked by comparison with the actual damage patterns. The proposed integrated architectural-structural approach permits a deeper comprehension of the structural principles that characterize Vanvitelli’s construction modulus and to estimate its seismic vulnerability.

Seismic Vulnerability of Sub-Structures: Vantitelli’s Modulus in Murena Palace

Structural identification is one of the most important steps when dealing with historic buildings. Knowledge of the parameters, which define the mechanical properties of these kinds of structures, is fundamental in preparing interventions aimed at their restoration and strengthening, especially if they have suffered damage due to strong events. In particular, by using non-destructive techniques it is possible to estimate the mechanical characteristics of load-bearing structures without compromising the artistic value of the monumental buildings. In this paper, after recalling the main theoretical aspects, the use of elastic waves propagation through impact tests for the characterization of the masonry walls of a monumental building is described. The impact test allowed us to estimate the elastic characteristics of the homogeneous solid equivalent to masonry material. This confirms the great potential of the non-destructive diagnostics suitable for analyzing important structural parameters without affecting the preservation of historical masonry structures.

Elastic Properties Estimation of Masonry Walls through the Propagation of Elastic Waves: An Experimental Investigation

Thermography is a non-destructive and non-contact technique allowing, without taking samples, gaining information about several aspects of heritage buildings. This contribution presents the last phase of a research path, started with laboratory tests and now aimed at a real case of great cultural value, which involved the use of the thermal imaging camera to unveil in-depth defects and the wall texture, hidden by valuable plasters or frescoes, in order to correlate the quality of the masonry to its mechanical properties. For this, a method has been devised, made of an original integration of thermographic and post-processing techniques, and recently was applied for the first time to a real case study: the Italian Templar church of San Bevignate, part of an architectural complex from the 13th century located in the city of Perugia. The opportunity to establish the masonry quality of a historical building using non-destructive testing (NDT) represents a little-known possibility to frame not only important factors for the conservation of the frescoes but also information on the seismic vulnerability of historical masonry architectures in order to preserve the artefact from being damaged during the surveys and to plan any effective intervention of restoration and structural reinforcement.

Feasibility of a Thermography Nondestructive Technique for Determining the Quality of Historical Frescoed Masonries: Applications on the Templar Church of San Bevignate

Vulnerability and seismic improvement of architectural heritage: the case of Palazzo Murena

The paper is aimed at assessing the shape irregularities effect on the collapse conditions of circular masonry arches in presence of horizontal actions. Historical constructions often present structural elements characterized by irregular shapes, which could affect their bearing capacity if calculated considering the nominal geometry. Some of these irregularities can be ascribed to the arising of deformed states developed over time or, in other cases, directly to technological construction processes. As a first study, the geometrical uncertainties related to construction processes are considered. In order to take into account such irregularities type, a random model of a polycentric arch has been developed.

The Role of Shape Irregularities on the Lateral Loads Bearing Capacity of Circular Masonry Arches

A multidisciplinary approach embedded with sustainability represents a pathway to design strategies applicable in different cultural contexts. Considering the emissions attributed to building processes, the design of conservation measures is evolving to create high performance both in terms of healthiness and safety. On this, heritage buildings in earthquake-prone cities proved their vulnerability during the recent seismic events. However, the most important aspect of restoration interventions is that the design process must respect the architectural peculiarities of the building. In this regard, the contribution presents the reuse of a heritage building, currently disused, in the novel role of University of Perugia’s plaster cast gallery, in line with the aims declared by the University with the adoption of the “Action Plan for University Sustainability 2021–2023”. Such architecture is part of Palazzo Murena, University of Perugia headquarters, a former monastery designed by Luigi Vanvitelli and completed in 1762 by Carlo Murena. A historical-iconographical investigation, together with a survey, revealed the building origin: a pre-existing architecture, anciently a hospice, included by Vanvitelli in their project. The purpose was the masonries’ reinforcement conceiving, at once, a flexible space according to the adaptive architecture principle: give to buildings configurations new, whole or in part, from the original ones in response to emerging threats. An integrated project was designed to restore the building in order to realize a contemporary museum in which full-height exhibition spaces alternate with the pre-existing ones. In this way, the new Gypso|TechA showcases the academic plasters, actually without a seat matching their cultural value, and through a peculiar layout encodes the collection’s message in a site-specific cognitive process.

https://www.mdpi.com/2071-1050/14/11/6857/pdf?version=1654756621

Riccardo Liberotti

Papers

Seismic Vulnerability of Sub-Structures: Vantitelli’s Modulus in Murena Palace

Vulnerability and seismic improvement of architectural heritage: the case of Palazzo Murena

Feasibility of a Thermography Nondestructive Technique for Determining the Quality of Historical Frescoed Masonries: Applications on the Templar Church of San Bevignate

The Role of Shape Irregularities on the Lateral Loads Bearing Capacity of Circular Masonry Arches

Built Environment’s Sustainability: The Design of the Gypso|TechA of the University of Perugia