Seguridad residual en los forjados con corrosión severa

En muchos casos de forjados con patología severa se observa que no existen daños importantes en los elementos constructivos. Incluso con todos los nervios con la armadura inferior corroída en muchas ocasiones no hay una fisuración alarmante ni de solados ni de tabiquería. Esta investigación analiza los mecanismos resistentes que colaboran y evalúa la seguridad remanente para los casos de corrosión en los forjados más habituales en los edificios de viviendas: los forjados unidireccionales de nervios de hormigón armado y de viguetas prefabricadas con los cantos más habituales. La evaluación de la seguridad remanente se ha realizado mediante el análisis del edificio completo, con cada una de las armaduras activas y pasivas en su posición real y con la aparición de cada uno de los elementos estructurales y constructivos en el modelo en el momento que dicta la realidad constructiva. El análisis de todo el rango de carga hasta el colapso se realiza mediante unos pasos de carga que tienen en cuenta el proceso de entrada en carga real: las concargas, la carga de servicio, la corrosión, y la carga hasta el fallo. Los modelos contemplan la no linealidad geométrica y de los materiales, con el aplastamiento y la fisuración del hormigón y la plastificación del acero. Para aceptar los resultados obtenidos se realiza una validación exhaustiva debido a que no se disponen de ensayos experimentales en edificios completos. Se han simulado diferentes elementos simples de hormigón armado y pretensado con armadura sana y corroída sometidos a distintas solicitaciones realizados por otros investigadores, obteniendo gran concordancia en los resultados. Los resultados se extraen de un modelo de edificio que recoge las luces habituales en edificios de viviendas. Los resultados son coherentes con la realidad, en donde en los casos de existir hasta 3 nervios contiguos con corrosión completa el forjado prácticamente no deforma y puede mantenerse en uso, y en los casos de tener corroído el armado inferior de todos los nervios de un forjado todavía se mantiene en pié, manteniendo cierta capacidad portante. Dentro de los casos de forjados unidireccionales con corrosión severa del armado inferior, los ejecutados con viguetas prefabricadas poseen mayor capacidad de carga remanente que los armados. Esto es debido a que los nervios armados in situ no poseen más armadura longitudinal a positivos, y los nervios pretensados sí, ya que contienen más capas de torzales pretensados que no están corroídos y permiten equilibrar la sección. Aunque los resultados obtenidos son acordes con los casos reales, es conveniente realizar un seguimiento, un mantenimiento o una reparación de la patología, dependiendo del estado de deterioro, que garantice la seguridad de uso del edificio.Vercher Sanchis, JM. (2013). Seguridad residual en los forjados con corrosión severa [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/27705TESI

Study of the Mechanical Behavior against Horizontal Forces of Self-supporting Facades

[EN] The brick facades are one of the most used facades in the current architecture. This typology is used during centuries, but still relevant today. The conventional way to build a brick facade is supporting the outer sheet on the slabs of the building. In buildings with these conventional facades have appeared stability, insulation and sealing problems. The self-supporting facade appears to solve these problems easily. This type of facade can solve more easily thermal bridges in buildings, which is an optimization of energy consumption. To resist horizontal forces facades need anchors between the two sheets or between the outer sheet and the structure. The current standards in Spain do not define the arrangement of the anchorages between the exterior sheet and the inner sheet of the enclosure. This paper studies the influence of the inner sheet in self-supporting facades. The transmission of horizontal forces between the two sheets of the facade is analyzed in detail, in order to check whether the inner sheet assists in the stability of the outer sheet. Different models of facade have been simulated to compare their results using the finite element method.Cubel Arjona, FJ.; Roldan, J.; Vercher Sanchis, JM.; Gil Benso, E. (2014). Study of the Mechanical Behavior against Horizontal Forces of Self-supporting Facades. Advanced Materials Research. 1041:27-30. doi:10.4028/www.scientific.net/AMR.1041.2727301041A. Mas, F. Cubel, Cerramientos de obra de fábrica, SPUPV, Valencia, (2005).R. Da Silva Vicente, J.A. R Mendes da Silva, Defects of non-loadbering masonry due to partial basal supports, Construction and Building Materials, 21 (2007) 1977-(1990).C. Del Río, Sistema Structura para fachadas de ladrillo cara vista. Conarquitectura, 25 (2008) 81-91.Eurocode No 6, Common Unified Rules for Masonry Structures, Report EUR 9888 EN. (1992).Commission Générale de Normalisation du Bâtiment, Documents Techniques Unifiés. DTU 20, Maçonnerie (1990).K. Zhu, E. Zhu, W. Yang, Finite element Analysis of Reinforced Brick Wall with Opening Hole. Advanced Material Research (2011) 243-249.K. Dilrukshi, E. Dias, R. Rajapakse, Numerical modelling of cracks in masonry walls due to thermal movements in overlying slab", Engineering Structures 32 (2010).F. Cubel, J. Vercher, A. Mas, E. Gil, Design and construction recommendations for brick enclosures with continuous air chamber, Construction & Building Materials 36 (2012) 151-164

Analysis of Energy Efficiency in Construction Solutions at the Facade-slab Connection

Façade-slab connection is the main thermal bridge of buildings. In this work, different options are analyzed according to the location of the thermal insulation. Heat loss is measured for each option. According to thermal analysis performed we conclude that cover the building¿s façade completely without interruption at the slab¿s front is essential to avoid thermal bridges. The new option that interrupts the cantilever to put insulation on the entire façade is just effective to isolate the entire cantilever and is an easier constructive solution. This insulation continuity is needed to prevent ceiling condensation, since the energy saving is not important compared to windows thermal loss.Vercher Sanchis, JM.; Lerma Elvira, C.; Vidal Martinez, M.; Gil Benso, E. (2013). Analysis of Energy Efficiency in Construction Solutions at the Facade-slab Connection. Advanced Materials Research. 787:731-735. doi:10.4028/www.scientific.net/AMR.787.731S731735787He, J., Hoyano, A., Asawa, T. A numerical simulation tool for predicting the impact of outdoor thermal environment on building energy performance. Applied Energy 86 (2009) 1596–1605. DOI: 10. 1016/j. apenergy. 2008. 12. 034.Füllsack-Köditz, R. Bauphysikalische Kennwerte für Balkonplattenanschlüsse. Bauphysik 34 (2012), Heft 3, pp.121-129. DOI: 10. 1002/bapi. 201200015.Sami A. Al-Sanea, M.F. Zedan. Effect of thermal bridges on transmission loads and thermal resistance of building walls under dynamic conditions. Applied Energy 98 (2012) 584–593. DOI: 10. 1016/j. apenergy. 2012. 04. 038.ZT Ai, CM Mak, JL Niu, ZR Li. Effect of balconies on thermal comfort in wind-induced, naturally ventilated low-rise buildings. Building Serv. Eng. Res. Technol. 32, 3 (2011) p.277–292. DOI: 10. 1177/0143624410396431.Lerma, C., Mas, Á., Gil, E., Vercher, J., Peñalver, MJ. Identification of construction material pathologies in historical buildings using infrared thermography. Materiales de Construcción (2013) pp.24-34. DOI: 10. 3989/mc. 2013. 06612

Methodology for Thermal Behaviour Assessment of Homogeneous Façades in Heritage Buildings

[EN] It is fundamental to study the thermal behaviour in all architectural constructions throughout their useful life, in order to detect early deterioration ensuring durability, in addition to achieving and maintaining the interior comfort with the minimum energy consumption possible. This research has developed a methodology to assess the thermal behaviour of facades in heritage buildings. This paper presents methodology validation and verification (V & V) through a laboratory experiment. Guidelines and conclusions are extracted with the employment of three techniques in this experiment (thermal sensors, thermal imaging camera, and 3D thermal simulation in finite element software). A small portion of a homogeneous facade has been reproduced with indoor and outdoor thermal conditions. A closed chamber was constructed with wood panels and thermal insulation, leaving only one face exposed to the outside conditions, with a heat source inside the chamber that induces a temperature gradient in the wall. With this methodology, it is possible to better understand the thermal behaviour of the facade and to detect possible damage with the calibration and comparison of the results obtained by the experimental and theoretical techniques. This methodology can be extrapolated to the analysis of the thermal behaviour of facades in heritage buildings, usually made up of homogeneous material.Gil Benso, E.; Lerma Elvira, C.; Vercher Sanchis, JM.; Mas Tomas, MDLA. (2017). Methodology for Thermal Behaviour Assessment of Homogeneous Façades in Heritage Buildings. Journal of Sensors. 1-13. doi:10.1155/2017/3280691S11

Structural Flexural Bending Assessment of Prestressed Concrete Joist with Corrosion

[EN] The number of situations where it is necessary to intervene in existing structures is increasing. In Spain, rehabilitation and maintenance of buildings accounts for 30% of the activity of the construction sector and it is growing. This paper evaluates the residual safety of T prestressed joists with severe corrosion at the lower reinforcement. The reliability is assessed with the application of the ACI-318 load test. It is demonstrated that there is sufficient safety in cases of corroded prestressed joists. At any rate, it¿s recommended to make a light repair under the damaged joists.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C. (2013). Structural Flexural Bending Assessment of Prestressed Concrete Joist with Corrosion. Advanced Materials Research. 790-793. doi:10.4028/www.scientific.net/AMR.671-674.790S790793Concrete Spanish Group (GEHO): Survey pathology of concrete structures, edited by GEHO Bulletin Vol 10, Madrid (1992).A.F. Barbosa and G.O. Ribeiro: Analysis of reinforced concrete structures using Ansys nonlinear concrete model. Computational Mechanics Vol. 1 n. 8 (1998), pp.1-7.P. Fanning: Nonlinear models of reinforced and post-tensioned concrete beams. Electronic Journal of Structural Engineering Vol. 2 (2001), pp.111-119.D. Coronelli and P. Gambarova: Structural assessment of corroded reinforced concrete beams: modeling guidelines. Journal of Structural Engineering Vol. 130 n. 8 (2004), pp.1214-1224.J. Vercher: Safety residual forged in severe corrosion. PhD. Department of Architectural Constructions. Polytechnic University of Valencia (2013).T. Tavio and A. Tata: Predicting nonlinear behavior and stress-strain relationship of rectangular confined reinforced concrete columns with Ansys. Civil Engineering Dimension Vol. 11 (2009).American Concrete Institute (ACI): Building Code Requeriments for Structural Concrete (ACI 318-08) and Commentary. Strength Evaluation of Existing Structures. Michigan, USA (2008).Prevalesa SL: Technical specifications - as EHE-08 - the slab of prestressed beams DITECO T12 model. Valencia, Spain (2008).Ministry of Housing: Technical Building Code (CTE), edited by Gazette, Madrid (2006)

Flexural Strengthening of Damaged T-Joists with Severe Corrosion Using CFRP Sheets

[EN] This paper evaluates the residual safety of isolated T-joists with severe corrosion for the two extreme cases of boundary conditions, simply supported and fixed-ended, in order to help in making decisions about the magnitude of the necessary intervention. When the T-joist is part of a complete slab, the boundary conditions will be in an intermediate situation between these two extreme cases, so that it is possible to assess the safety with respect to its degree of embedding. The research is conducted for the cases of healthy T-joist, T-joist with complete corrosion of the lower reinforcement, and repaired T-joists with a variable number of CFRP sheets. This work is based on the ACI 318 load test to maintain a structure in use and proposes a Load Factor (LF), which estimates the safety reserve. The simply supported T-joists specimens with severe corrosion do not meet the Load Factor or ACI 318 criteria, even with a large number of CFRP sheets. On the other hand, fixed-ended cases can be kept in use despite corrosion by applying light CFRP strengthening, and with four sheets the initial safety is restored.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C.; Torner Feltrer, MEM. (2017). Flexural Strengthening of Damaged T-Joists with Severe Corrosion Using CFRP Sheets. Advances in Materials Science and Engineering. 2017:1-9. doi:10.1155/2017/6030357S19201

Evaluación del índice de seguridad real en las construcciones

Póster presentado en la sesión dedicada a Ámbitos, Innovación y Calidad, en las IV Jornadas Internacionales sobre Investigación en Arquitectura y Urbanismo.Este trabajo tiene como intención evaluar el índice de seguridad real calculando la carga última de una construcción y compararla con la que nos proporcionan los métodos de cálculo clásicos. Para este análisis se modeliza en el programa de elementos finitos Ansys la estructura en tres dimensiones y sus secciones como sólidos. Se contempla el comportamiento real de los materiales, teniendo en cuenta la no linealidad, fisuración, aplastamiento, plastificación, fluencia y endurecimiento por tensión de las armaduras. Empleamos nuestro método para poder analizar el índice de seguridad restante cuando existe una patología, como cuando desaparece el armado inferior de una vigueta. El modelo lo hemos contrastado con resultados de ensayos experimentales de elementos sencillos, como una viga armada en T a flexión, y un fragmento de pilar a compresión. En estos momentos estamos realizando el modelo de sólidos de una estructura compleja: viguetas, capa de compresión, vigas y pilares.Gil Benso, E.; Vercher Sanchis, JM.; Mas Tomas, MDLA. (2012). Evaluación del índice de seguridad real en las construcciones. http://hdl.handle.net/10251/1495

Exposure factors influence in stone deterioration by crystallization of soluble salts

The present work tries to determine the factors that influence the crystallization of soluble salts in the stone material used in the construction of buildings in Valencia (Spain). Samples are obtained from a building which has served to accomplish observations and laboratory experiments necessary in order to determine the pathology of deterioration of the material. It was particularized in the exposition conditions of the material as a base for determining the morphologies of deterioration caused by salts in the same lithotype. The main contribution is the petrological study from the architectural point of view considering its orientation, sunlight in fac¸ade, and so forth. This study proves that both material petrology (its mineralogy and texture) and the properties related to the movement of water inside rocks play a decisive role in the conservation and development of elements in the alteration.Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C.; Vercher Sanchis, JM. (2015). Exposure factors influence in stone deterioration by crystallization of soluble salts. Advances in Materials Science and Engineering. 2015:1-10. doi:10.1155/2015/348195S1102015Cultrone, G., Russo, L. G., Calabrò, C., Uroševič, M., & Pezzino, A. (2007). Influence of pore system characteristics on limestone vulnerability: a laboratory study. Environmental Geology, 54(6), 1271-1281. doi:10.1007/s00254-007-0909-1Benavente, D. (2004). Role of pore structure in salt crystallisation in unsaturated porous stone. Journal of Crystal Growth, 260(3-4), 532-544. doi:10.1016/j.jcrysgro.2003.09.004Binda, L., Cardani, G., & Zanzi, L. (2010). Nondestructive Testing Evaluation of Drying Process in Flooded Full-Scale Masonry Walls. Journal of Performance of Constructed Facilities, 24(5), 473-483. doi:10.1061/(asce)cf.1943-5509.0000097Ioannou, I., Hall, C., Wilson, M. A., Hoff, W. D., & Carter, M. A. (2003). Direct measurement of the wetting front capillary pressure in a clay brick ceramic. Journal of Physics D: Applied Physics, 36(24), 3176-3182. doi:10.1088/0022-3727/36/24/013Buj, O., López, P. L., & Gisbert, J. (2010). Caracterización del sistema poroso y de su influencia en el deterioro por cristalización de sales en calizas y dolomías explotadas en Abanto (Zaragoza, España). Materiales de Construcción, 60(299), 99-114. doi:10.3989/mc.2010.50108Flatt, R. J. (2002). Salt damage in porous materials: how high supersaturations are generated. Journal of Crystal Growth, 242(3-4), 435-454. doi:10.1016/s0022-0248(02)01429-xVeniale, F., Setti, M., & Lodola, S. (2008). Diagnóstico del deterioro de la piedra en el patrimonio construido. Datos y perspectivas. Materiales de Construcción, 58(289-290), 11-32. doi:10.3989/mc.2008.v58.i289-290.85Grossi, C. M., & Esbert, R. M. (1994). Las sales solubles en el deterioro de rocas monumentales. Revisión bibliográfica. Materiales de Construcción, 44(235), 15-30. doi:10.3989/mc.1994.v44.i235.579Fort, R., Fernández-Revuelta, B., Varas, M. J., Alvarez de Buergo, M., & Taborda-Duarte, M. (2007). Influencia de la anisotropía en la durabilidad de las dolomías Cretácicas de la Comunidad de Madrid frente a la cristalización de sales. Materiales de Construcción, 58(289-290), 161-178. doi:10.3989/mc.2008.v58.i289-290.7

Basalt FRP rods assessment as an alternative reinforcement for reinforced concrete

[EN] The consequences of global warming are becoming increasingly disastrous. Nowadays, our society has the responsibility of reducing the energy consumed in the building sector. In order to reduce this 40% of emissions, applying sustainable development criteria is fundamental throughout the life of materials in construction. More specifically, the use of steel corrugated bars or rods as reinforcement is the most widely used product in concrete reinforcement, and it is therefore important to reduce its climate impact. Basalt Fibre Reinforced Polymers (FRP) is a promising alternative to replace these steel reinforcements due to its high strength, low weight and high durability capabilities.This work compares different rebars in sustainable terms in an initial phase. Four different materials are studied: steel, stainless steel, glass FRP and basalt FRP. To check and verify the different geometrical and mechanical properties, four rods of each material are tested in the laboratory. Finally, an analysis and comparison of various sustainability aspects is carried out. The aim of this research is to find out which reinforcing bar is the most sustainable and whether the basalt FRP rod is as optimal as it promises to be.Vercher Sanchis, JM.; Vidal, T.; Torres, J.; Lerma Elvira, C.; G. Borràs, J.; Gil Benso, E.; Mas Tomas, MDLA. (2023). Basalt FRP rods assessment as an alternative reinforcement for reinforced concrete. Editorial Universitat Politècnica de València. 240-248. https://doi.org/10.4995/VIBRArch2022.2022.1529524024

Recomendaciones constructivas y de diseño para la distribución de las conexiones de la hoja exterior de un cerramiento con cámara de aire continua

[ES] La optimización de la disposición de las conexiones es necesaria para garantizar la estabilidad de la hoja exterior de un cerramiento con cámara de aire continua, para un mejor funcionamiento y durabilidad de la fachada. En este trabajo se proponen diferentes disposiciones para los anclajes a la estructura y diferentes tipos de hoja interior, con el objetivo de seleccionar el mejor para el comportamiento de la fachada frente a las acciones del viento en los casos de edificios de viviendas. Un aumento muy significativo de la rigidez se observa simplemente colocando los anclajes a la estructura alternadamente a un lado y al otro del elemento estructural, y aún más cuando hay llaves entre las hojas del cerramiento, especialmente a una hoja interior de ladrillo.[EN] The optimization of connections arrangement to guarantee the anchored veneers with continuous air cavity stability is necessary, for better performance and durability of the façade. In this paper, different arrangements for the anchors to structure and different kinds of inner leaf are proposed, with the aim of selecting the best for the behavior of the façade against wind actions in cases of residential buildings. A very significant increase in stiffness is observed simply placing the anchors to the structure alternately to one side and the other of the structural element, and it is still more when there are wall ties between leaves, especially to a brickwork inner leaf.Mas Tomas, MDLA.; Vercher Sanchis, JM.; Cubel Arjona, FJ.; Gil Benso, E.; Lerma Elvira, C. (2018). Design and construction recommendations for connections arrangement in anchored veneers with continuous air cavity. Revista de la Construcción (Online). 17(1):137-148. https://doi.org/10.7764/RDLC.17.1.137S13714817