Luong test for the characterization of the shear post-cracking response of fiber reinforced concrete

The behavior of concrete subjected to shear can be significantly improved by the addition of fibers, which may partially or totally substitute the traditional steel stirrups (also known as links). Design recommendations include formulations to account for the contribution of the fibers. However, these formulations take the results of small-scale bending tests as input parameters. The main reason for that is the lack of standardized tests and the difficulty to assess direct shear in fiber reinforced concrete (FRC) both for the design and for the quality control. The present study proposes a test for the characterization of the post-cracking shear response of FRC. The test is validated through an experimental program with conventional concrete and FRC. The influence of different parameters (geometry of the specimen, the type and the content of fiber) is assessed and a comparison is made between the push-off test and the one proposed here. Results of an in-depth statistical analysis indicate that the latter is a simpler and valid alternative to evaluate the post-cracking shear response of FRC.Peer ReviewedPostprint (author's final draft

A hierarchical integration method under social constraints to maximize satisfaction in multiple criteria group decision making systems

Aggregating multiple opinions or assessments in a decision has always been a challenging field topic for researchers. Over the last decade, different approaches, mainly based on weighting data sources or decision-makers (DMs), have been proposed to resolve this issue, although social choice theory, focused on frameworks to combine individual opinions, is generally overlooked. To resolve this situation, a novel methodology is developed in this paper based on social choice theory and statistical mathematics. This method innovates by dividing the assessment into components which provides a multiple assessment analysis, assigning weights to each source regarding their position compared to the group for each considered criteria. This multiple-weighting process maximises individual and group satisfaction. Furthermore, the method makes it possible to manage previously assigned influence. An example is given to illustrate the proposed methodology. Additionally, sensitivity analysis is performed and comparisons with other methods are made. Finally, conclusions are presented.The first author acknowledges support from the Spanish Ministry of Education, Culture and Sports [grant number FPU18/01471]. The second and third author wish to recognise their support from the Serra Hunter programme. Finally, this work was supported by the Catalan agency AGAUR through its research group support program (2017SGR00227). This research is part of the R&D project IAQ4EDU, reference no. PID2020-117366RB-I00, funded by MCIN/AEI/10.13039/501100011033.Peer ReviewedPostprint (published version

A systematic review on multi-criteria group decision-making methods based on weights: analysis and classification scheme

Interest in group decision-making (GDM) has been increasing prominently over the last decade. Access to global databases, sophisticated sensors which can obtain multiple inputs or complex problems requiring opinions from several experts have driven interest in data aggregation. Consequently, the field has been widely studied from several viewpoints and multiple approaches have been proposed. Nevertheless, there is a lack of general framework. Moreover, this problem is exacerbated in the case of experts’ weighting methods, one of the most widely-used techniques to deal with multiple source aggregation. This lack of general classification scheme, or a guide to assist expert knowledge, leads to ambiguity or misreading for readers, who may be overwhelmed by the large amount of unclassified information currently available. To invert this situation, a general GDM framework is presented which divides and classifies all data aggregation techniques, focusing on and expanding the classification of experts’ weighting methods in terms of analysis type by carrying out an in-depth literature review. Results are not only classified but analysed and discussed regarding multiple characteristics, such as MCDMs in which they are applied, type of data used, ideal solutions considered or when they are applied. Furthermore, general requirements supplement this analysis such as initial influence, or component division considerations. As a result, this paper provides not only a general classification scheme and a detailed analysis of experts’ weighting methods but also a road map for researchers working on GDM topics or a guide for experts who use these methods. Furthermore, six significant contributions for future research pathways are provided in the conclusions.The first author acknowledges support from the Spanish Ministry of Universities [grant number FPU18/01471]. The second and third author wish to recognize their support from the Serra Hunter program. Finally, this work was supported by the Catalan agency AGAUR through its research group support program (2017SGR00227). This research is part of the R&D project IAQ4EDU, reference no. PID2020-117366RB-I00, funded by MCIN/AEI/10.13039/ 501100011033.Peer ReviewedPostprint (published version

Influence of the type of fiber on the structural response and design of FRC slabs

Most codes for the design of fiber reinforced concrete (FRC) structures are based on the experience achieved throughout the years with steel fibers. Recent codes include the possibility of applying the same considerations for FRC structures with plastic fiber. However, the consequences of assuming identical design considerations regardless of the type of fiber is scarcely known in terms of the structural behavior of full-scale elements. The main goal of this paper is to assess the influence of the type of fiber on the performance of full-scale concrete slabs, emphasizing on the consequences of using a common design approach. For that, a comparative experimental study was conducted in order to expose differences regarding the crack pattern and load-deflection behavior. Then, finite element simulations were performed using the constitutive equations from the Model Code 2010. The results indicate distinct levels of overestimation of the structural behavior measured experimentally, confirming that specific design considerations are required depending on the type of fiber used. Based on the findings, correction factors are proposed for the design of FRC slabs with each fiber.Peer ReviewedPostprint (author's final draft

Dovelas de hormigón (concreto) reforzado con fibras para el soporte de túneles y pozos verticales

El empleo del hormigón reforzado con fibras (HRF) para dovelas de anillos de revestimiento de túneles es ya una práctica habitual a nivel nacional e internacional. En este sentido, las ventajas técnicas a las que conduce su uso (control del ancho de fisura, tenacidad frente a impacto y cargas concentradas, entre otras) son también conocidas. Asimismo, a nivel económico su uso puede ser atractivo si se hace un análisis integral considerando el proceso de producción y mantenimiento de la dovela, y no sólo la comparación del coste (costo) de la fibra y el de la armadura. Aún existe inercia al empleo del HRF como alternativa al refuerzo clásico; pues su contribución estructural raramente se ha considerado. Por una parte, debido a que hasta el año 2008 no aprobó la EHE – 08, cuyo anexo 14 aborda aspectos de diseño y control de HRF; y, por otra, a la falta de criterios para considerar aspectos como la orientación y distribución de las fibras.Peer ReviewedPostprint (published version

Compensación de la calidad del aire interior, el confort térmico y el consumo de energía para edificios educativos

In recent years, poor indoor air quality and thermal comfort have been widely reported in related studies on indoor environmental quality in classrooms. Improving indoor air quality through ventilation is common and effective. However, it compromises occupant’s thermal comfort and well-being, thereby consuming more energy to meet increased heating or cooling demand and challenging energy conservation for Sustainable Development Goal 7. The existing researches imply the significance of conducting an extensive review on the three domains mentioned above (indoor air quality, thermal comfort, and energy consumption) in educational buildings, as individual cases are of peculiarity due to the specific characteristics of buildings and occupants. In contrast, the standards for indoor air quality and thermal comfort in educational buildings are not explicit and unified for all countries. This paper summarizes relevant features from reviewed cases, including: the geographic and demographic characteristics, field investigation parameters, indoor air quality and thermal comfort standards, ventilation protocols, heating and cooling strategies, energy consumption, as well as important and valuable findings in order to investigate the progress on such a topic.Objectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantPostprint (published version

A systematic review on MIVES: a sustainability-oriented multi-criteria decision-making method

Sustainability has practically become a mandatory concept to be considered in every decision, and multiple decision-making methods have been adapted to take it into account. Among them, sustainability centred methods are also known as sustainability assessments, which provides sustainability indexes to select and prioritize alternatives. One of these most recent presented techniques is MIVES, a multi attribute utility theory multi-criteria decision-making value function-based method initially developed to introduce environmental and social indicators in civil engineering design decisions and later adapted for general evaluation and prioritization of homogenous and heterogeneous alternatives. Over the last decade, it has been widely studied and applied to specific situations, but a MIVES summary is currently lacking. Therefore, in this paper MIVES literature is reviewed with a deep bibliometric analysis carried out to provide on multiple data about MIVES state-of-the-art. Furthermore, a thematic clusters categorisation is done to reveal the usefulness of MIVES as design and decision-making tool, cataloguing the wide applications of MIVES as sustainability index. Finally, a MIVES characteristics discussion is carried out to help researchers deepen their knowledge towards the method and highlight potential future research pathways.The first author acknowledges the Goverment of Spain: Ministry of Education, Culture and Sports [grant number FPU18/01471]. The second and last author wishes to recognize the support from Serra Hunter programme. Finally, this work was supported by Catalan agency AGAUR trough their research groups support program (2017SGR00227). This research is part of the R&D project IAQ4EDU, reference no. PID2020-117366RB-I00, funded by MCIN/AEI/10.13039/501100011033.Peer ReviewedPostprint (published version

Eco-trench: a novel trench solution based on reusing excavated material and a finishing layer of expansive concrete

Installing utility pipelines generates a significant amount of trench arisings, which are usually transported to landfills instead of being reused as backfill material. This practice generates CO2 emissions and wastes raw materials. This paper presents a more sustainable solution, an eco-trench, which is based on re-using trench arisings as backfill and adding a top layer of expansive concrete to improve the eco-trench’s structural performance. The technical feasibility of the eco-trench was evaluated through a finite element model, which identified the degree of expansion in concrete required to avoid failure or subside the stresses caused by traffic. The potential expansion of concrete was measured under confined conditions in the laboratory by means of a novel test developed for this purpose. The results showed that adding calcium oxide generates the required internal stress. The results were then confirmed in a pilot experience.Peer ReviewedPostprint (published version

MIVES multi-criteria approach for the evaluation, prioritization, and selection of public investment projects. A case study in the city of Barcelona

A meaningful contribution to the evaluation of heterogeneous public investments is described in this article. The proposed methodology provides a step towards sustainable urban planning in which decisions are taken according to clear, consistent and transparent criteria assisted by the MIVES multi-criteria analysis framework. The MIVES methodology combines multi-criteria decision making (MCDM) and multi-attribute utility theory (MAUT), incorporating the value function (VF) concept and assigning weights through the analytic hierarchy process (AHP). First, a homogenization coefficient is calculated to develop the Prioritization Index for Heterogeneous Urban Investments (PIHUI), so that non-homogenous alternatives may be comparable. This coefficient measures the need of society to invest in each public project through the consideration of its contribution to the regional balance, the scope of its investment, the evaluation of the current situation and the values of the city. Then, the MIVES multi-criteria framework is used to evaluate the degree to which each investment would contribute to sustainable development. Different economic, environmental and social aspects were considered through a decision framework, constructed with the three aforementioned requirements, five criteria and eight indicators. The case study conducted for the Ecology, Urban Planning and Mobility Area of Barcelona municipal council is presented in this article, showing how this method performs accurate, consistent, and repeatable evaluations.Peer ReviewedPostprint (author's final draft

Sustainable deployment of energy efficient district heating: city business model

Heating and cooling account for 50% of the European Union's energy consumption and, therefore, reducing its impact is essential to minimise dependency on energy imports (particularly fossil fuel), which are bound to geopolitical conflicts. District heating arises as a critical player in this transition towards a more efficient energy framework. Despite its numerous advantages, implementation is still hindered by inadequate District Heating business models and incentives. This study conducts a holistic examination on the feasibility, effectiveness and, ultimately, the efficiency of establishing a publicly owned and public-privately managed District Heating infrastructure network via a pilot intervention in the city of San Sebastian in the north of Spain. A Value Proposition Canvas, Value Creation Ecosystem and City Model Canvas analysis provides insight into fundamental patterns and relevant recommendations for other municipalities trying to find a business model in which all the involved stakeholders can capture value while addressing at the same time the energy challenges of cities.Authors would like to acknowledge the direct and timely collaboration with experts from San Sebastian. The authors acknowledge the support from the European Union’ Horizon 2020 Research and Innovation Programme’ under the grant agreements No 6917535 (REPLICATE Project). This work was supported by Catalan agency AGAUR trough their research groups support program (2021 SGR 00341). Finally, authors wishes to recognise the support from Serra Hunter programme.Peer ReviewedObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.1 - Per a 2030, garantir l’accés universal a serveis d’energia assequibles, confiables i modernsObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energiaObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.3 - Per a 2030, duplicar la taxa mundial de millora de l’eficiència energèticaObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les personesObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.2 - Promoure una industrialització inclusiva i sostenible i, a tot tardar el 2030, augmentar de manera significativa la contribució de la indústria a l’ocupació i al producte interior brut, d’acord amb les circumstàncies nacionals, i duplicar aquesta contribució als països menys avançatsObjectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.2 - Incorporar mesures relatives al canvi climàtic en les polítiques, les estratègies i els plans nacionalsObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.1 - Per a 2030, assegurar l’accés de totes les persones a habitatges i a serveis bàsics adequats, segurs i assequibles, i millorar els barris marginalObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.b - Per a 2020, augmentar substancialment el nombre de ciutats i assentaments humans que adopten i posen en marxa polítiques i plans integrats per promoure la inclusió, l’ús eficient dels recursos, la mitigació del canvi climàtic i l’adaptació a aquest, així com la resiliència davant dels desastres, i desenvolupar i posar en pràctica una gestió integral dels riscos de desastre a tots els nivells, d’acord amb el Marc de Sendai per a la reducció del risc de desastres 2015.2030Postprint (published version