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Testing the Influence of Metakaolinite and Zeolite on the Adhesion of BFRP and GFRP Bars to Concrete
No full textToday’s sustainable development policy in Europe, which is driven by concerns about the greenhouse effect and environmental protection, mandates a reduction in CO2 emissions into the atmosphere. The cement industry and steel mills that produce reinforcing bars are among the largest and most emissions-intensive sectors emitting CO2 into the atmosphere. This article analyzes the possibility of achieving significant reductions in CO2 emissions by using basalt bars (BFRP) and glass bars (GFRP) in concrete structures, and—in the case of concrete—by using cement with the addition of metakaolinite and zeolite. There is a lack of literature reports on whether modifying concrete with the additions of metakaolinite and zeolite as substitutes for part of the cement affects the adhesion of FRP bars to concrete. It can be assumed, however, that improving the microstructure of concrete also improves the contact zone between the bar and the concrete. The aim of this research is to fill the aforementioned gap in the literature data by determining how the presence of metakaolinite and zeolite affects the adhesion of reinforcing bars to concrete and testing selected properties of hardened concrete. The test samples were prepared following the appropriate beam test procedure. The obtained results made it possible to perform a comparative analysis of reference samples and those with metakaolinite and zeolite additions. The research showed that introducing active pozzolanic additives in the form of metakaolinite and zeolite into concrete improved adhesion stress values by approximately 20% for glass GFRP bars and 15% for basalt BFRP bars, especially in the destruction phase
Synchronisation among short-term rental markets, co-movements and cycles in 39 European cities
No full textThis paper presents new evidence of the short-term rental market's prices and transactions from a daily time-series perspective in 39 European cities from 2015 to 2020. It uses Airbnb micro datasets to build time-series cycles by extracting the original observations containing total bookings (rent transactions), rental units supply, and asking rent, with a daily periodicity. The cycles show the periods in which short-rental activity was more relevant for each city, and the level of rents across Europe. The paper provides empirical evidence of a long-term relationship among the city variables (tested via mean and variance). Causality supporting co-movements across cities was found by estimating a short-term naïve market equilibrium model using the vector error correction model approach, supporting the hypothesis that the short-term rental market performs according to housing-market principles. Short-run elasticities among rents and contracts across the 39 cities show causal evidence of co-movements among rents and the supply and demand of properties. The market adjustment on the supply side estimates new units responding to changes in prices within 15 lags (days) and longer (350 lags) from the demand side, equivalent to eight to nine months. Evidence of the pandemic's limited effect on housing supply and prices' positive effect is also provided. A robust negative weekend impact on prices was found, suggesting stronger market relevance on weekdays
A Proposal for a Methodology of Documentation to Be Applied to an Altarpiece Conservation and Restoration Project
No full textDocumenting altarpieces according to their formal characteristics and three-dimensionality is a challenge that we can currently address through the use of documentation techniques already used in the immovable cultural heritage field. This study includes the process of developing a digital model of an altarpiece that, through an approach to HBIM methodology, captures its physical configuration to be turned it into a holder of information on technical aspects, state of conservation and interventions carried out. This process contemplates a previous stage of approximation to the object of study, the definition of the uses of the model, and the configuration of a collaborative environment from which information can be added and exchanged. The academic use of the three-dimensional model will guarantee the comprehensive knowledge of the altarpiece, being initially a model for reference and later for management, by recording the interventions carried out by the students, for didactic and dissemination purposes
Placemaking at a time of changing port city relations
No full textCities around the world, from New York, to London and Hong Kong, lost much of their shipping functions within decades after the opening of new container terminals on their outskirts. Many port authorities and city governments adapted their ports rapidly to maintain their city’s edge in a tight competition. Over the last five decades, as public and private decision-makers around the world built new ports and facilities for the increased transhipment of goods and people, responding to similar challenges and opportunities, developing new ports, dredging waterways, transforming storage and transhipment in response to changing ship sizes, new containers or new commodity flows, the old waterfronts in New York, Hamburg, Amsterdam, Philadelphia and Sydney lost their leadership function as global ports. They became ghost districts, challenges to urban development. Spaces that hosted port activities in the nineteenth and early twentieth centuries contain heritage buildings and industrial structures on a scale that can be repurposed for urban functions that are often well connected to urban sites and infrastructure. In recent decades these sites have become hubs of urban growth and tourism. Many cities had to develop new strategies for the inner-city ports that had fallen empty and for the large number of people who had lost their jobs in packaging, transportation and storage
Graphene nanofibers: A modern approach towards tailored gypsum composites
No full textEnergy poverty is a global challenge that demands sustainable and affordable solutions. This study investigates the use of commercial graphene nanofibers (GNFs) as a reinforcing agent in gypsum composites for energy-efficient building retrofitting. The GNFs were manually dispersed in the gypsum matrix, and the composites were fabricated by casting and curing. The thermomechanical properties were systematically studied using various characterization techniques, including scanning electron microscopy, X-ray diffraction, and thermal analysis. The results show that the addition of 1% GNFs reduces the thermal conductivity of the composites by more than 40% and improves their flexural and compressive strength by up to 23 and 42%, respectively, compared to neat gypsum. The enhancements are attributed to the effective phonon scattering of the GNFs and their ability to act as crystal seeding sites, resulting in a denser and more homogeneous structure. The dynamic thermal analysis further demonstrates that the GNF-reinforced composites could reduce heating and cooling requirements by 14 and 11%, respectively, indicating their potential for energy-efficient building retrofitting. However, the cost effectiveness and safety issues of the GNF-reinforced composites should be carefully considered before their large-scale implementation. Achieving uniform dispersion of nanoparticles in high concentrations is also a significant challenge that will be addressed in future studies
Neighbourhood Sustainability Assessment Tools for Sustainable Cities and Communities, a Literature Review—New Trends for New Requirements
No full textThe aim of this documentary review was to determine the level of scientific production on environmental analysis tools and certifications for sustainable cities and communities, or “Neighbourhood Sustainability Assessment Tools”, worldwide between the years 2016 and 2023, considering as a precedent the appearance of the SDG 2030 and SDG 11. The analysis developed in this work was carried out based on WoS, Scopus and ScienceDirect. The eligibility of the results of 685 potential articles, in addition to complementary articles, was evaluated, leading to 27 selected reviews. Our analysis revealed the main and most recent results post implementation of sustainability measures, identifying limitations, success factors, trends and forecasts for the future selection, development or improvement of evaluation tools for the sustainability of human sites and describing strategies specific to local realities, which are valid from a global point of view but include the particularities of distinct communities in specific places
Estimation of heating system energy modeling profiles based on environmental monitoring records in Central-Southern Chile
No full textData simulated for occupancy profiles, usually based on standard occupancy schedules, must be validated against real measurements, and many studies have pointed out the gap between them. This problem is more pronounced in homes that are not heated by grid-connected energy sources, such as wood-burning stoves, because the meter cannot provide a real-time estimate. In Central-South Chile, 74% of homes are heated by wood stoves, causing an acute problem of air pollution in several urban areas. The government is trying to solve this problem, but at the moment there is no data on occupancy profiles, hence it is not possible to estimate the energy intensity for heating. This exploratory study aims to clarify to what extent occupancy profiles can be estimated from PM 2.5 pollution levels. To this end, publicly available data on PM 2.5 concentrations in 17 cities in central-south Chile was used as a proxy to build occupancy schedules for homes heated by wood stoves. The results show that there is a clear relationship between pollution levels and occupancy intensity, and that the latter does not follow the schedules outlined in international standards or building codes. The results and methodology can be replicated in cities where air pollution is driven by wood stoves, allowing public authorities to have access to accurate occupancy schedules and providing them with reliable data to address local air pollution problems
Decreased useful life in air chamber reinforced concrete elements under sanitary floors by carbonation corrosion
No full textReinforced concrete elements located in enclosed spaces with medium to high humidity, inside air chambers beneath sanitary floors, are shielded from rainfall. However, the longevity of these elements, as estimated by durability models for predicting the corrosion of their reinforcement due to carbonation, significantly exceeds the actual service lives observed. The discrepancy between estimated and actual service lives often results in structural failures of sanitary floors, which may collapse without warning, given the inherent challenges associated with inspection and maintenance. This study thoroughly examined the condition of reinforced concrete elements beneath sanitary floors in four educational institutes located in the Valencian Community, where corrosion of reinforcement due to carbonation was present. The study entailed an analysis of the relative humidity, temperature, and presence of CO2 within these enclosed spaces, in comparison to exterior areas or other parts of the building. Furthermore, tests were conducted to assess the characteristic strength of the concrete and the depth of carbonation. Additionally, the surface area of the chamber used for ventilation was assessed in light of the minimum requirements. Notwithstanding, the concrete cover of the beams and columns exhibited carbonation, with the reinforcement's corrosion in a propagation period. The study's findings revealed that the service life of the structural elements is substantially shorter than initially anticipated, in part due to advanced carbonation processes that are attributable to the harsh environment in which they are located
The Royal Tobacco Factory of Seville. Representation of the State Versus Functionality
No full textThis paper conducts a study of the functionality of a building for industrial use of the largest in Europe in the eighteenth century, the Royal Tobacco Factory of Seville. It analyses the relationship between site, space, design and construction valuing the military engineers involved in the project and the direction of the works, with an academic training oriented to respond to fortification works, far from the development of industrial projects. As a symbol of the architecture of power represented by the State, it conveyed the idea of an empire that stood above other kinds of restrictions of the time. With the advent of new inventions such as automation and mechanisation, the space was gradually equipped with new machinery until the building was finally destined for a use far removed from its origins, namely as a military barracks and headquarters of some university faculties and the Rectorate, conveying the idea of malleability that responds to unprojected future demands
El impacto de la inteligencia artificial y BIM en la Arquitectura Técnica
Get PDFLa era de la transformación digital ha impulsado la inteligencia artificial (IA) al centro del escenario en una multitud de sectores. Desde la atención médica, donde la IA ayuda en diagnósticos precisos y tratamientos personalizados, hasta el sector financiero, donde revoluciona la seguridad y la eficiencia de las transacciones, la IA ha demostrado ser una herramienta poderosa y transformadora. En el ámbito de la tecnología y la ingeniería, ha permitido avances significativos en automatización y optimización de procesos. La arquitectura técnica no ha sido una excepción a esta ola de innovación. La adopción de IA en este campo está abriendo puertas a nuevas formas de diseñar, planificar y construir, redefiniendo los límites de lo posible en la creación de espacios y estructuras. Como responsable de nömad, una agencia que se sitúa entre la publicidad y la tecnología, he observado de primera mano cómo la IA puede ser un socio estratégico en el proceso creativo y técnico. Nuestra misión es desafiar lo establecido, incorporando soluciones que anticipan tendencias y necesidades, tanto en publicidad como en estrategias digitales. Esta experiencia me permite aproximarse sobre la posible sinergia entre la IA y la arquitectura técnica, presagiando una revolución en cómo los profesionales del sector conciben y pueden llevar a cabo sus proyectos. Este artículo tiene como objetivo explorar la influencia creciente de la inteligencia artificial y del Modelado de Información de Construcción (BIM) en la arquitectura técnica. El informe del American Institute of Architects (AIA) resalta cómo la IA y el BIM están cambiando fundamentalmente la manera en que los profesionales de la construcción abordan sus proyectos. Desde la fase de diseño hasta la finalización de un edificio, estas tecnologías ofrecen un enfoque más integrado y eficiente, permitiendo una mayor precisión en la planificación y una mejor gestión de los recursos. La integración de la IA y el BIM promete no solo mejorar la eficiencia y la sostenibilidad en la arquitectura técnica, sino también fomentar una mayor innovación en el diseño, abriendo nuevas posibilidades para la creación de espacios que sean tanto estéticamente impresionantes como funcionalmente robustos