Abstract

This paper aims to present, via a case study, an interdisciplinary approach towards the comprehensive analysis of historic constructions. The case study monument examined is the Medieval Manor of Potamia in Cyprus. The work hereby presented was based on a collaboration between scientists from the fields of archeology, architecture, materials science/ conservation and structural engineering. A thorough review of historical sources was initially carried out in order to obtain data concerning the history and construction development of the Manor. Extensive field work was undertaken to study the architectural typology and construction detailing of the structures and to explicitly map the various agents of pathology. For the characterization of the historic fabric, masonry materials were sampled and studied at the laboratory. The accumulated data facilitated the development of a Finite Element (FE) model, which was used to numerically assess the structure’s seismic response.

Abstract

This paper shows the experimental and numerical analysis developed on a brick masonry wall of 3x2.5x0.2 m to understand the changes on its dynamic behaviour with different stiffness situations: (i) original, (ii) loaded with different load levels, (iii) damaged by horizontal in plane loads, (iv) retrofitted with Textile Reinforced Mortars (TRM) and (v) retrofitted and damaged by horizontal in plane loads. This analysis has been developed at the Civil Engineering Lab at the University of Alicante. On this masonry wall a matrix of 8 seismic accelerometers have been installed to evaluate, in plane and out of plane, changes in the main frequencies, modal damping ratios and modal shapes. By the use of Operational Modal Analysis techniques the results shows that the changes on the stiffness have important influence on the main frequencies and in the modal damping ratios. Very low influence have been detected on the modal shapes due to the low level of external vibrations generated during the tests. Due to the low level of vibrations inside the lab,the classical application of ambient vibrations for OMA has been not possible and an external white noise force has been introduced on the top the wall by the use of a shaker to generate a general level of vibrations on the specimen.

Abstract

The international cultural and historical heritage is often subject to degradation and damage. The main causes contributing to these phenomena are the chemical and mechanical actions due to acid rain, environmental pollution, and earthquakes. Other causes are the cycles of freezing and thawing that induce the manifestation of internal stresses leading to the deterioration of the material and the collapse of structural parts. In the field of architectural restoration, this problem has been addressed by two main solutions. The first involves cleaning processes that leave the missing parts visible; the second consists of introducing reproductions of the missing parts, creating a clear distinction between pre-existing and new elements. In both cases, the seismic behavior of the structure is modified; in the second solution, the added elements do not contribute to the structural strength since they are made of plaster or stucco. This work aims at presenting a preliminary study on the creation of replacements of missing elements within damaged heritage buildings. The work is structured in two distinct phases. In the first phase, specific cubic specimens, created with a 3D printer, are produced and subjected to uniaxial compression tests. The experimental campaign is carried out in order to provide useful information regarding the 3D material engineering constants that are currently absent in the literature. In the second phase, the experimental results are used in a numerical model to calibrate the mechanical properties of an equivalent homogeneous material.

Abstract

Current massive data capture techniques (MDCT), such as terrestrial laser scanning and digital photogrammetry, have become widespread during the last decade, and raises the possibility of developing new assessment methodologies based on the 3D documentation. The paper exposes de results of using simple, non-invasive procedures for the assessment of the shape of a masonry building from a point clouds registered with a terrestrial laser scanner. The case study selected is the church of Sant Miquel of Batea (eighteenth century), located in the province of Tarragona (Spain). The methodology used combines 2D and 3D processes for assessment of the geometry. The results of the investigation have confirmed the good condition of the building. It presents dimensional variations, most of which can be related to the construction process, while some displacements identified provide information about the accommodation process of the masonry structure.

Abstract

Recent seismic events that hit the Centre Italy have highlighted the high vulnerability of the historical and architectonical heritage that is the richness of the country, pointing out once again the difficulty of the assessment of monumental buildings such as churches or historical palaces, due to their uniqueness, the absence of a design, the limitation of invasive in situ tests, but the importance of the knowledge to understand the seismic behavior more than the static analysis under the gravitational loads. In the present paper the knowledge procedure is framed considering the case study of an important nineteenth century astronomical observatory, constructed in 1816-1819. The building, located in Naples, in the southern of Italy, classified by the Italian code as an area of medium seismic hazard, is analyzed by the use of integrated investigation activities such as coring, flat jack tests, georadar to obtain all the information due to the variability of the materials and the influence of previous alterations and repairs, that are data all necessary to develop a reliable model.

Abstract

At the end of the 19th century, an architectural style called Neomudéjar became quite popular in some areas of Spain. Very much like other historicist European styles in the same years, the Neomudéjar sought to recreate the local medieval architecture. The use of faced brick façades with complicated bonds -formed by stretchers and headers in and out the main wall plane- lead in term to a wide variety of results that resembled Arabic architecture. The brick façades of the Neomudéjar buildings are ideal case studies for the analysis of the local behaviour of masonry structures, especially regarding problems of stress concentration. There are several methods for studying the global behaviour of masonry structures – from the classic thrust line to the limit analysis tools – but, as the average stresses taken over by structural masonry elements are usually well below the compression strength of the constituent material, the classical methods of analysis are designed to verify only the global stability. Local behaviour, on the other hand, is quite elusive, especially when the properties of the material are uncertain. In such cases stress concentrations might appear, resulting on stress currents and low stress islets. A particular case of these phenomena occurs in the bonding of Neomudéjar façades. Local concentration of stresses is especially likely in these bonds, given the peculiar relative position of some bricks with respect to others. The paper proposed will use one of these buildings, the Aguirre Schools (Rodríguez Ayuso, Madrid, 1886), as a case study to evaluate local behaviour. Starting from a geometrical hypothesis of the internal distribution of the material based on recent photogrammetric surveys, and using conventional software of parametric design, the paper will describe a numerical model based on a non-deterministic random algorithm, although limited in its number of solutions, to discuss later the validity and scope of them. The limitations of the standard hardware in which these design tools are usually handled will also be considered in the discussion.

Abstract

Earthen architecture is one of the most relevant building technologies among heritage structures. However, mechanical properties are commonly obtained from destructive tests. To contribute at changing this trend, two non-destructive mechanical techniques (ultrasound and modal analysis) are studied to determine their ability at characterizing earthen materials and their possible correlation. To achieve these purposes, twenty cubic-shaped earthen specimens were produced for testing the capability of ultrasound transmission method to control moisture content and its evolution during drying process at different environments. Additionally, a real-scale rammed earth wall was built to assess the feasibility of using ultrasound technique to determine elastic dynamic Young modulus. This analysis was validated by indirect comparison with experimental modal analysis test results. The most important findings are that the relationship between moisture content and ultrasound transmission speed is linear. This information is useful to control the drying process of earthen materials and to control the moisture content distribution on larger in-service structures. Finally, numerical simulation using ultrasound transmission data as input information allow to predict the vibrational response of the tested wall with an error around 3%.

Abstract

A real case of consolidation works is presented in which only field testing methods can reveal the causes of instability. This paper is an update of the one presented at the SAHC 2018 conference, concerning the study of the partial collapse of the Church of Itria in Piazza Armerina (Sicily, Italy). The previous paper beared hypotheses and design solutions based only on indirect investigations, theoretical formulations and checks with software. The consolidation works, started in November 2018 and still in progress, have made it possible to formulate new and documented hypotheses on the collapse and to integrate and partly modify the solutions hypothesized previously. In particular, the reconstruction techniques of the wall and chains have been confirmed. The new interventions have, instead, concerned the consolidation of the foundation soil which was found to be insubstantial,following electrical tomographic investigations, due to the presence of voids. At the same time, inspections were carried out on an old masonry sewage pipe which revealed several points of discontinuity through which large quantities of water entered under the walls of the church causing the removal of inconsistent elements from the ground. At first, the reconstruction of the collapsed wall was done and the restoration of the existing wall structures, to eliminate the causes of the collapse through the intervention on the sewage pipe and filling the voids under the foundations. The most important intervention, which required the use of innovative materials, forefront equipment and skilled labor, involved the filling the voids under the foundations through perforations every 50 cm, both on the inner and outer wire of the collapsed wall. Clamped canes were set in order to intercept the voids highlighted by the tomography. A 100% expansive mortar was injected at low pressure through the canes, filling one cane at a time and progressively raising the point of exit of the mortar until the higher far end. After this consolidation, the foundation and the wall were rebuilt with local limestone ashlars to have fair faced aspect as the original masonry. At the end of the work, further tomographic tests are planned to verify the validity of the interventions carried out.

Abstract

The Church of the Laboral University of Gijón has the world's largest elliptical masonry roof with 40.8 meters of mayor axis. This big structure is vertically supported with no columns using twenty pairs of masonry ribs crossing each other, and horizontally supported by means of two elliptical ring beams located at the top of the Church. In order to study this historical building, this paper presents the overall three-dimensional structural numerical analysis of the Church, taking into account different material nonlinearities - including masonry and reinforced concrete - as well as geometrical nonlinearities, such as contact effects among the different structural components of the building. Furthermore, a coupled thermal-structural analysis was carried out considering the summer temperature distribution and the Spanish standard rule dead and live loads. The most relevant results, in terms of maximum displacement, stress and, cracking and crushing phenomena are presented. Finally, valuable information from the interaction among the structural elements of the Church are discussed and the most critical points of the building are located, giving place to the most important conclusions of the nonlinear numerical analysis of this interesting structure.

Abstract

This paper describes the design, test and validation processes of a dynamicidentification algorithm aimed at the time-dependent assessment of modern structures and heritage buildings for civil and seismic engineering purposes. Full validation of the algorithm is performed through analysis of numerically simulated data from an idealized masonry tower. Making use of output-only vibration measurements, the non-parametric algorithm can generate dynamic features results as time-dependent functions for the complete observation period. The algorithm can work in the presence of different dynamic loads and non-linear structural behaviours, close spectral frequency components and noisecontaminated data. Time-dependent structural dynamic parameters that can be computed are modal frequencies, modal displacements, modal curvatures, and higher derivatives of mode shapes. The proposed algorithm aims to be used as the core estimator of timedependent identification methods devoted to the health monitoring of structures and infrastructures, being suitable for a multitude of tasks ranging from the simple operational modal analysis (in pre and post-event condition) to the complex online assessment of the structural response during seismic events for rapid damage identification.