Consideration of the non-linear behavior materials in the structural analysis of the church of Santa Ana in Sevilla by finit elements method

The purpose of this paper is to bring the numerical models' structural behavior closer to the real behavior of the Church of Santa Ana in Seville, in Triana, through the development of high-definition geometric models that incorporate the non-linear materials' behavior. This church is presented as a unique case study due to the geometric complexity of its vaults and the influence on the structural behavior of the constructive solution of its passable roof. A geometrical model has been developed “as i”t, adapting the various constructive solutions to the real building. The result is a ”high definition geometrical model”. To define the materials a dynamic identification campaign has been carried out using OMA (Operational Modal Analysis) that has allowed us to adjust the mechanical properties of these materials in the numerical models. Modal shapes and frequencies of vibration similar to those obtained in the environmental vibration campaign has been obtained. A first linear analysis give us an approximation and a magnitude order of the displacement levels and the stress state, and let us to locate areas that exceed the admissible level stresses of the defined materials. With these results and analyzing in situ the displacement levels using photogrammetry, we decide to implement in the numerical analysis a constitutive model that contemplates the nonlinear behavior of these materials with Concrete Damage Plasticity model in Abaqus Cae. A non-linear analysis has been performed increasin the gravity factor until the structural collapse to determinate the structural safety factor

Determining static elastic modulus of weak sandstone in Andalusian historical constructions from non-destructive tests: San Cristóbal's stone

This work presents a relationship between static and dynamic elastic moduli for San Cristóbal’s stone, which was used to build some of the most representative historical constructions in Andalusia (Spain) during 15th-18th centuries, including religious, military and civil buildings. Numerical models are able to provide useful information in structural health assessment of historical constructions, but static elastic modulus is necessary to perform them. This is why it is particularly interesting to count on an equation to predict this parameter from others, such as dynamic elastic modulus, which can be obtained in situ and through tests based on wave propagation. A new relationship is proposed after having shown that equations previously defined by other authors are not valid for San Crist´obal’s stone. The prposed relationship in this work is based on a set of physical and mechanical experimental tests carried out in lab on 17 specimens directly extracted from support elements of Santiago’s (Jerez de la Frontera, Cádiz-Spain). Linear, polynomial and nonlinear multiple regressions were considered, as well as the inclusion of other parameters, such as bulk density and porosity. However, an equation with a coefficient of determination of 0.95 was achieved with a simple regression where only dynamic elastic modulus was involved. This simple equation allows to predict static modulus of San Cristóbal’s Stone with a high level of confidence and only from one parameter, that can be obtained in situ through non-destructive techniques and respectfully to built heritage. Finally, a first approximation to the application on an ancient construction is provided. Six columns of the Monastery of San Jerónimo de Buenavista, in Seville (Spain) underwent tests based on the propagation of wave to determine in situ their dynamic elastic modulus. The In situ results for the dynamic elastic modulus are consistent with those obtained in lab

Meta-modelling for fast prediction of the effective elastic properties of cement mortar doped with CNT

This article presents an innovative metamodeling approach for predicting the effective elastic properties of cement grouts containing carbon nanotubes (CNTs), for the purpose of structural rehabilitation. The study addresses the homogenization of nano- and micro- scales through a Representative Volume Element (RVE). The numerical model consists of a cement matrix doped with randomly oriented CNTs, yet the computational load associated with this model poses a significant processing limitation. To overcome this challenge, a metamodeling approach based on a Kriging surrogate model is proposed. This approach provides a fast and accurate alternative to bypass the timeconsuming numerical homogenization process. The surrogate model establishes a connection between the microstructural characteristics of CNTs, cement, and the effective elastic properties of the composite grouts. The accuracy and efficiency of the proposed metamodel are demonstrated through detailed analyses

Updating models of finite elements by modal operational analysis and genetic algorithms. Application to architectural heritage built

The use of Operational Modal Analysis is establishing as an acceptable tool to estimate the dynamic properties of heritage buildings as a non‐destructive technique. Through its application, mechanical properties of structural elements, as stiffness or mass, can be obtained with great accuracy. The information obtained can be used to update finite element models, however this process is complicated due to presently it is made manually. This work wants to develop a technique which expects improve the effort and the time invert in this process. The genetic algorithms are going to be used to update tow finite element models of tow patrimonial buildings, the Pavilion of Charles V and the San Jeronimo Monastery both located in Seville, in which variables like elasticity module or boundary conditions are going to be updating in order to have a real behaviour model to carry out the structural assessment of the buildings

Identificación de las propiedades mecánicas de la piedra de San Cristóbal mediante técnicas no destructivas

La alteración de la Piedra arenisca es una inquietud para los técnicos y restauradores del patrimonio histórico, ya que es la piedra base de muchos edificios de nuestro patrimonio histórico. En este trabajo nos vamos a centrar en la piedra extraída en el Cerro de San Cristóbal, situada en el Puerto de Santa María (Cádiz). Una de las características de esta piedra es un material muy degradable, que unido a las alteraciones provocadas por el paso del tiempo y por los agentes atmosféricos están poniendo en peligro parcial o totalmente algunos de los edificios históricos más importantes de nuestra región. El objetivo de este trabajo consiste en contribuir a la caracterización mecánica de la piedra del Cerro de San Cristóbal, utilizando métodos físicos y geofísicos. Para desarrollar este trabajo contamos con una serie de probetas pertenecientes a la Iglesia de Santiago de Jerez de la Frontera, las cuales se han obtenido extrayendo varios testigos en el sentido paralelo al eje de las columnas. La caracterización de sus propiedades físicas se ha centrado en la determinación de su densidad, (seca, sumergida y saturada), porosidad abierta, absorción, volumen de poros, volumen aparente, mientras que sus propiedades mecánicas se ha determinado mediante ensayos dinámicos, determinando su módulo de deformación identificando sus frecuencias naturales de vibración. Dicha campaña dinámica se ha realizado a diferentes niveles de humedad seca 0%, y saturadas al 40%, 80% y el 100%. La identificación de sus propiedades mecánicas se ha realizado basándonos en la norma UNE 14146

Characterization of the sandstone of the San Cristóbal Hill as a resistant material in historical buildings: the case of the Church of Santiago, from Jerez de la Frontera (Cádiz)

La piedra objeto de la presente investigación estudio procede de la Iglesia de Santiago de Jerez de la Frontera. Es un material muy utilizado en la construcción de los edificios del patrimonio histórico. Se trata de una piedra arenisca que pertenece a la cantera del Cerro de San Cristóbal que, por diferentes motivos económico, logísticos y de trabajabilidad, ha sido muy utilizada en importantes edificios construidos a lo largo del valle del Guadalquivir Sevilla, Jerez de la Frontera, Puerto de Santa María, San Fernando, Cádiz, Utrera, incluso llegando a utilizarse en la Catedral de Málaga. Los edificios históricos, por lo general suelen estar bajo criterios de protección patrimonial. Esto implica no sólo la necesidad de su conservación sino también la responsabilidad de garantizar su integridad estructural, especialmente cuando forman parte de edificaciones que aún están en uso. En estas dos últimas décadas se han acometido obras importantes en nuestro patrimonio, ejemplo la catedral de Sevilla se han sustituido dos pilares (5) y se realizan periódicamente trabajos de consolidación y sustitución de sillares perteneciente a los muros. También en la Iglesia del Salvador de Sevilla se han reforzado todas las estructuras de la iglesia pilares, bóvedas, muros debido a la degradación de la piedra. Y en la Iglesia de Santiago de Jerez de la Frontera, Cádiz, se han generado numerosas patologías estructurales que comenzaron a finales del siglo XVII y desde esta fecha y en varias ocasiones, han sido necesarias labores de rehabilitación y refuerzos estructurales. La piedra arenisca de estudio ha sido estudiada y se han realizado distintas publicaciones que, denotan un claro interés, por su conservación profundizando el conocimiento de los aspectos físico, y químico, además de su caracterización petrográficas para optimizar los tratamientos a aplicar a la piedra, que mejoran su durabilidad. Sin embargo, el análisis de su comportamiento mecánico no se ha llegado a tratar en profundidad, desde un punto de vista estructural, ni la influencia que provoca en las propiedades mecánicas, la presencia de la humedad. Los estudios realizados a otras piedras areniscas no son de aplicación a nuestra piedra ya que tienen diferentes características. Si tenemos en cuenta la mayoría de las fábricas de piedra en estructuras históricas están a la intemperie, por lo que están sujetas a cambios de humedad ambiental, otras están afectadas por la humedad de capilaridad, pudiendo llegar a altas cotas con diferentes niveles de contenido de humedad (%), incluso en las zonas más altas de la edificación pueden verse afectadas por filtraciones de la cubierta. Es ampliamente conocido que las propiedades mecánicas de las piedras naturales utilizadas como materiales estructurales de construcción se ven afectadas negativamente por la humedad. El poco conocimiento del comportamiento mecánico de la piedra arenisca del Cerro de San Cristóbal, provoca una gran incertidumbre en los técnicos y restauradores que tienen que tomar decisiones de cómo intervenir en el patrimonio histórico, ya que esta piedra es el elemento principal, que asume competencias estructurales, al constituirse como un material fundamental de los muros y pilares. Por tanto, un adecuado conocimiento de la piedra aseguraría un mayor rigor en la toma de decisiones por dichos técnicos. La investigación desarrollada pretende proporcionar un modelo de análisis, planteando un método no destructivo, con el que conocer sus propiedades mecánicas, además de obtener los fundamentos necesarios para poner de manifiesto el estado real en que se encuentra la piedra y su repercusión en el comportamiento de la estructura del edificio, incluso tenido en cuenta la afección que provoca la presencia de la humedad.The stone object of this research study comes from the Church of Santiago de Jerez de la Frontera. It is a material widely used in the construction of historical heritage buildings. It is a sandstone that belongs to the Cerro de San Cristóbal quarry which, for different reasons ‐ economic, logistical and workability ‐ has been widely used throughout the Guadalquivir valley: Seville, Jerez de la Frontera, Puerto de Santa María, San Fernando, Cádiz (1), Utrera (2.3), even being used in the Cathedral of Málaga (4). Historic buildings are generally under heritage protection criteria. This implies not only the need for their conservation but also the responsibility to guarantee their structural integrity, especially when they are part of buildings that are still in use. In the last two decades, important works have been undertaken in our heritage, for example, the Cathedral of Seville, two pillars (5) have been replaced, and consolidation and replacement works of ashlars belonging to the walls are carried out periodically. Also in the Church of El Salvador in Seville, all the structures of the church, pillars, vaults, walls have been reinforced due to the degradation of the stone. And in the Church of Santiago de Jerez de la Frontera, Cádiz, numerous problems have arisen that began at the end of the 17th century and since then and on several occasions, rehabilitation work has been necessary. The sandstone under study has been studied and different publications have been carried out, denoting a clear interest in its conservation, deepening the knowledge of the physical and chemical aspects (6), (7), (8), in addition to its characterization. petrographic (9) to optimize the treatments to be applied to the stone, which improve its durability (10), (11). However, the analysis of its mechanical behavior has not been dealt with in depth, from a structural point of view, nor the influence that the presence of humidity causes on the mechanical properties. The studies carried out on other sandstones (12), (13), (14) are not applicable to our stone since they have different characteristics. If we take into account most of the stone factories in historical structures are outdoors, so they are subject to changes in environmental humidity, others are affected by capillarity, and can reach high levels with different levels of moisture content, even in the highest areas of the building they can be affected by leaks from the roof. It is widely known that the mechanical properties of natural stones used as structural building materials are negatively affected by humidity (15). The little knowledge of the mechanical behavior of the sandstone of the Cerro de San Cristóbal, causes great uncertainty in the technicians and restorers who have to make decisions on how to intervene in the historical heritage, since this stone is the main element, which assumes competences structural, being constituted as a fundamental material of the walls and pillars. Therefore, an adequate knowledge of the stone would ensure greater rigor in decisionmaking by said technicians. The research developed aims to provide an analysis model, proposing a non‐destructive method, with which to know its mechanical properties, in addition to obtaining the necessary foundations to reveal the real state in which the stone is found and its repercussion on the behavior of the structure of the building, even taking into account the condition caused by the presence of humidity. To articulate the analysis model, it is necessary to analyze and identify the physical (density, porosity and absorption) and mechanical properties (static and dynamic longitudinal deformation modulus, as well as the uniaxial compression resistance) of each of the samples through a campaign experimental, considering different moisture contents. These techniques would increase their practical applicability, and with the support of some laboratory tests, data would be taken from different areas of the building, that is, it would be possible to know the state of the stone in many areas of the building affected by some pathology, in a campaign non‐destructive testing without having to rely on specimen extraction. This project has a unique opportunity to have stone samples extracted from the Church of Santiago de Jerez de la Frontera, during the last restoration carried out by D. Emilio Yanes Bustamante and D. Alejandro Cobo, samples that were extracted from the core of some columns and load‐bearing walls and of which we know their position in the building and their orientation with respect to the load axis of the building

Analysis and classification of tea varieties using high-performance liquid chromatography and global retention models

Medicinal plants produce bioactive molecules through their metabolic processes, which are crucial for human health and are used in treatments and pharmaceutical development. Chromatographic fingerprints obtained with solvent gradients help authenticate and categorise these plants by capturing their chemical diversity. This work focuses on optimising tea sample analysis in HPLC using a model-based approach that does not require standards. By predicting the effects of gradient profiles on full signals, optimal separation conditions were identified. Global models characterised retention and bandwidth for 14 peaks across various elution conditions, allowing for the optimisation of 63 peaks, which accounted for 99.95% of the total peak area. The optimal gradient was then applied to classify 40 samples from six tea varieties. Matrices of baseline-corrected signals, elution bands, and band ratios were evaluated to select the best dataset. Principal Component Analysis (PCA), k-means clustering, and Partial Least Squares-Discriminant Analysis (PLS-DA) were used to assess classification feasibility, revealing reasonable limitations due to the complexities of tea processing, including drying and fermentation affected by environmental conditions

Influence of moisture content on the mechanical properties of an ancient high-porosity building sandstone: San Cristóbal's stone (Andalusia, Spain)

San Cristóbal’s is a porous sandstone that is present in masonry structures of numerous historical buildings located in the southwest of Spain (15th–18th centuries). In order to guarantee conservation and structural integrity, most of these structures have been assessed during the last two decades after they presented severe damages in locations affected by moisture. In this study, static and dynamic elastic modulus and uniaxial compressive strength of San Cristóbal’s stone are determined in the laboratory under dry and saturated states, as well as with a moisture content of 40%, to establish the influence of moisture on them. An experimental campaign was conducted on 16 samples of ancient stone, extracted from the core of structural walls and columns during a structural intervention. The results show how the moisture content directly affects the deformability of the stone, especially between dry and 40% moisture content states. The values of the elastic modulus, both static and dynamic, are reduced with average values of 16.98% and 22.85% respectively. The loss of uniaxial compressive strength between the dry and saturated states is established with a mean value of 29.82%. Additionally, empirical relationships between the studied mechanical properties have been developed, reaching coefficients of determination over 0.90 in most cases

Discovering HIV related information by means of association rules and machine learning

Acquired immunodeficiency syndrome (AIDS) is still one of the main health problems worldwide. It is therefore essential to keep making progress in improving the prognosis and quality of life of affected patients. One way to advance along this pathway is to uncover connections between other disorders associated with HIV/AIDS-so that they can be anticipated and possibly mitigated. We propose to achieve this by using Association Rules (ARs). They allow us to represent the dependencies between a number of diseases and other specific diseases. However, classical techniques systematically generate every AR meeting some minimal conditions on data frequency, hence generating a vast amount of uninteresting ARs, which need to be filtered out. The lack of manually annotated ARs has favored unsupervised filtering, even though they produce limited results. In this paper, we propose a semi-supervised system, able to identify relevant ARs among HIV-related diseases with a minimal amount of annotated training data. Our system has been able to extract a good number of relationships between HIV-related diseases that have been previously detected in the literature but are scattered and are often little known. Furthermore, a number of plausible new relationships have shown up which deserve further investigation by qualified medical experts

How do women living with HIV experience menopause? Menopausal symptoms, anxiety and depression according to reproductive age in a multicenter cohort

CatedresBackground: To estimate the prevalence and severity of menopausal symptoms and anxiety/depression and to assess the differences according to menopausal status among women living with HIV aged 45-60 years from the cohort of Spanish HIV/AIDS Research Network (CoRIS). Methods: Women were interviewed by phone between September 2017 and December 2018 to determine whether they had experienced menopausal symptoms and anxiety/depression. The Menopause Rating Scale was used to evaluate the prevalence and severity of symptoms related to menopause in three subscales: somatic, psychologic and urogenital; and the 4-item Patient Health Questionnaire was used for anxiety/depression. Logistic regression models were used to estimate odds ratios (ORs) of association between menopausal status, and other potential risk factors, the presence and severity of somatic, psychological and urogenital symptoms and of anxiety/depression. Results: Of 251 women included, 137 (54.6%) were post-, 70 (27.9%) peri- and 44 (17.5%) pre-menopausal, respectively. Median age of onset menopause was 48 years (IQR 45-50). The proportions of pre-, peri- and post-menopausal women who had experienced any menopausal symptoms were 45.5%, 60.0% and 66.4%, respectively. Both peri- and post-menopause were associated with a higher likelihood of having somatic symptoms (aOR 3.01; 95% CI 1.38-6.55 and 2.63; 1.44-4.81, respectively), while post-menopause increased the likelihood of having psychological (2.16; 1.13-4.14) and urogenital symptoms (2.54; 1.42-4.85). By other hand, post-menopausal women had a statistically significant five-fold increase in the likelihood of presenting severe urogenital symptoms than pre-menopausal women (4.90; 1.74-13.84). No significant differences by menopausal status were found for anxiety/depression. Joint/muscle problems, exhaustion and sleeping disorders were the most commonly reported symptoms among all women. Differences in the prevalences of vaginal dryness (p = 0.002), joint/muscle complaints (p = 0.032), and sweating/flush (p = 0.032) were found among the three groups. Conclusions: Women living with HIV experienced a wide variety of menopausal symptoms, some of them initiated before women had any menstrual irregularity. We found a higher likelihood of somatic symptoms in peri- and post-menopausal women, while a higher likelihood of psychological and urogenital symptoms was found in post-menopausal women. Most somatic symptoms were of low or moderate severity, probably due to the good clinical and immunological situation of these women